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1
Hussen, Walid Yass. "Investigation of the thermal and magnetic properties of some Ce-based heavy electron systems." Thesis, Loughborough University, 1990. https://dspace.lboro.ac.uk/2134/27939.
Full textAbstract:
The aim of this project was an investigation of the thermal and magnetic properties of highly correlated electron systems. To carry out the experiments it was necessary to design, construct and automate a calorimeter and a Faraday susceptibility balance. The calorimeter was used to determine the specific heat of powder samples from 1.5 K to 300 K using a pulse technique. Initially the performance of the calorimeter was verified using spectrographically pure copper samples. The specific heat of CePt2 and LaPt2 has been measured in the temperature range from 3 K to 100 K. The f-electron contribution to the specific heat of CePt2 was determined by subtracting the measured specific heat of isostructural LaPt2 from CePt2. This difference revealed a Schottky anomaly at temperatures between 15 K and 100 K. which enabled the crystal-field splitting of the J=5/2 ground state manifold of Ce3+ to be deduced.
2
Richards, Adrian John. "High gradient magnetic separation using ordered wire filters for the separation of human blood and bone marrow cells." Thesis, University of Southampton, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390731.
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Lozada, Luis O. "Reengineering the process of manufacturing thermal-cryogenics tanks." Online version, 2001. http://www.uwstout.edu/lib/thesis/2001/2001lozadal.pdf.
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Pezzetti, Marco. "Standard and experimental approach for advanced controls in cryogenics." Amiens, 2010. http://www.theses.fr/2010AMIE0127.
Full textAbstract:
Cette thèse présente la problématique des modèles et des systèmes de contrôle appliqués à certaines installations cryogéniques utilisées au CERN et exploite l'expérience accumulée pendant plus de dix ans lors de la construction, du développement et de la mise en route des installations cryogéniques du LHC. La première partie introduit (i) les bases de la cryogénie, tels les fluides cryogéniques, la théorie de transfert de chaleur, le concept de thermodynamique, (ii) les installations de test cryogéniques et les détecteurs au CERN. La deuxième partie donne une vue d'ensemble des techniques standards utilisées pour l'identification du système et la conception des lois de commande. La troisième partie présente une nouvelle approche théorique à la modélisation et au contrôle pour des systèmes cryogéniques à grande échelle, dont la formulation est appliquée sur le condensateur liquide à Krypton de l'expérience NA62. Premièrement, un modèle est dérivé d'équations de bilan sous la forme d'équations différentielles ordinaires (ODE) qui décrivent le flux de masse et le transfert de chaleur entre des fluides cryogéniques. La phase de modélisation est suivie d'une proposition d'une stratégie de contrôle avancé, le Time Delay Control, dont les performances, obtenues en simulation, est présentée en comparant avec les performances d'une boucle de régulation plus traditionnelle (correction PID). L'implémentation de la solution proposée a demandé une phase d'analyse plus approfondie afin d'estimer statistiquement les délais de communication rencontrés lors de la mise en marche du système ainsi contrôlé. La quatrième partie présente les principes de programmation et les outils informatiques actuellement utilisés au CERN pour gérer les installations cryogéniques. Pour terminer l'étude, des conclusions sont données à partir du travail théorique et pratique présenté avec une vue d'ensemble des nouvelles perspectives ouvertes par celui-ciThis thesis deals with the problem of modeling and control applied to some of the cryogenic plants currently used at CERN, and exploits the experience accumulated over more than ten years on the construction, deployment and operation of the LHC cryogenic installations. The first chapter introduces (i) the basics of cryogenics, such as cryogenic fluids, heat transfer theory, concepts of thermodynamics, and (ii) cryogenic test facilities and detectors at CERN. The second chapter gives an overview of the standard techniques used for system identification and control design. The third chapter presents a novel theoretical approach to modeling and control for large scale cryogenic systems, whose formulation is applied to the liquid Krypton condenser of the NA62 experiment. First, a model is derived from balance equations in the form of ordinary differential equations (ODE) describing the mass flow and the heat transfer between cryogenic fluids. The modeling phase is followed by the proposal of an advanced control strategy, the Time Delay Control, whose performances obtained in simulation are presented in comparison with those of a more traditional PID-based control loop, thus showing the improvement allowed by the new approach. The implementation of the proposed solution required a further phase of analysis in order to statistically estimate the communication time delays usually encountered during the operation of the system under control. The results of these analyses are also presented. The fourth chapter presents the programming paradigm and the software tools currently used at CERN to handle the cryogenic plants. The thesis ends with the discussion of the conclusions drawn by the theoretical and practical work presented in the previous parts, along with an overview of the new perspectives it has opened
5
Sagar, Pankaj. "Cryogenic Instrumentation using Planar Inductor based Eddy Current Sensors." Thesis, 2019. https://etd.iisc.ac.in/handle/2005/4465.
Full textAbstract:
Cryogenic sensors have become vital in the measurement of crucial parameters in modern scientific research. This work addresses the design, development and testing of planar inductor eddy current sensors and associated cold electronics for a
variety of cryogenic applications.
The first sensor designed is a multilayer planar inductor based eddy current proximity/displacement transducer. The initial part of the work focuses on the behaviour of PCB (FR4) based multilayer inductors at 4.2 K. The structural changes (warping) that were in the simulation studies were observed through the variation of capacitance between the layers of the inductors when the sensor was cooled. The second part of the work incorporates the designed multilayer inductor to develop a proximity sensor capable of measuring displacement in the range of (0-5mm) down to 4.2 K. Since the effective realization of the inductor based sensors require signal
conditioning elements to be close to the sensing element, the electronic circuits which are capable of working at cryogenic temperatures without any drastic changes in parameters or at least predictable changes in parameters were developed. A detailed study of performance analysis of unbuffered inverter-based LC oscillator development is also discussed. The developed sensor has good thermal stability, sensitivity and repeatability at the cryogenic operating temperatures.
The second sensor is a multilayer planar inductor array based eddy current angular position/rotation transducer working at 4.2 K using cold electronics signal conditioning circuits. A study on the rotor segments that would provide the most effective sensing (zero dead zone) is also done. The developed sensor is characterized for the entire temperature range (4.2 K – 300 K ) and shown to work satisfactorily.
The final set of sensors are designed to measure the Residual Resistivity Ratio (RRR) of Nb samples. RRR is an important parameter that dictates the purity and in turn, the performance of the Superconducting Radio Frequency (SRF) cavities at low temperatures (<4.2 K). Here, three different non - contact RRR measurement techniques are presented which utilize the eddy current principles. The initial approach uses the ratio of the slope of lift - off lines generated by the impedance variation when the conductivity of the Nb sample changes to obtain the RRR value. The second approach utilizes the inflection point, which relates eddy current penetration depth to the conductivity of the metal. The third approach correlates the inductance variation of the sensing coil with the RRR of the sample
through a cold electronics based multiplexed inductor LC oscillator circuit
6
NATICCHIONI, LUCA. "Low frequency noise suppression for the development of gravitational astronomy." Doctoral thesis, 2014. http://hdl.handle.net/11573/918208.
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The existence of gravitational radiation, predicted by the General Relativity theory, was indirectly demonstrated by the observation of the orbital decay in the binary pulsar 1913+16, for which R.A. Hulse and J.H. Taylor were awarded with the Nobel Prize in 1993. From then on, the direct detection of gravitational waves became a main issue in the experimental physics, not only for the verification of the theory itself but, most important, because it can open a new "observation window" of the universe. In fact, many astronomical objects, such as neutron stars and black holes, can be directly studied only through their gravitational emission. Moreover, since its interaction with matter is intrinsically weak, the degradation of informations carried by gravitational waves is negligible, and their revelation will allow us to understand the internal structure of massive objects which emit them, and will also provide a complementary point of view to the traditional astronomy and cosmology.
The direct detection must face the extreme weakness of gravitational radiation, hence very high sensitive detectors are required in order to reveal the quadrupolar effect produced by the passage of gravitational waves. The first attempts in this field were based on massive resonant bars, relying on the pioneering technique developed by J. Weber. In recent decades a more promising strategy based on interferometry was developed, providing the advantage of a wide-frequency detection-band (from few Hz to some kHz) jointly to an extreme sensitivity (the detectable strain is smaller than the size of a proton). The global network of first generation interferometric detectors, composed of Virgo, LIGO, GEO600 and TAMA300, demonstrated the feasibility of such a technique; in particular the kilometric-scale detectors Virgo and LIGO achieved a sensitivity high enough to determine the first upper limits for the gravitational emission of some known neutron stars, such as the Crab and Vela pulsars. In the next few years the upgraded version of these detectors, namely the second generation of detectors (such as Advanced Virgo and Advanced LIGO) will become operational and are expected to achieve the first direct detections of gravitational waves.
However, the signal-to-noise ratio (SNR) of these first detections will be too low for precise astronomical studies of the gravitational wave sources and for complementing optical, radio and X-ray observations in the study of fundamental systems and processes in the Universe.
For this reason the investigation on the design of a new, namely third, generation of detectors is already started, leading to the proposal of the European Einstein Telescope (ET). With a considerably improved sensitivity these new machines will open the era of routine gravitational wave astronomy, leading to the birth of a complete multimessenger astronomy. In particular, to enlarge the detector bandwidth in the range of 1 Hz, where interesting gravitational signals, such as those emitted by rotating neutron stars, can be detected, a further reduction of the so-called low-frequency noise, with respect to the second generation detectors, is required.
In this low-frequency band the main limitation to the sensitivity of an interferometric detector arises from the thermal noise, and at lower frequencies, from the seismic and Newtonian noises. The suppression of the thermal noise will require the implementation of a cryogenic apparatus, in order to cool the test masses down to about 10 K, so that the development of position-control devices capable of cryogenic operations will be also necessary for the suspension and payload control. The seismic attenuation was already obtained in first generation detectors by means of long suspension chains of vertical and horizontal oscillators (e.g. the superattenuator of Virgo), so that a further reduction requires a smaller seismic noise at the input of the suspension system; moreover, mass density fluctuations produced by the seismic motion induce also a stochastic gravitational field (the so-called Newtonian or gravity-gradient noise) which shunts the suspension and couples directly to the mirrors of the interferometer. In order to suppress these two seismically-generated noises, third generation interferometers will be constructed in underground sites, where Rayleigh surface waves are attenuated, and the surrounding rock layers are more homogeneous and stable, reducing the density fluctuations. The feasibility of a cryogenic and underground interferometer was already tested by the Japanese prototype-detector CLIO, in the same site where is currently under construction KAGRA (formerly known as LGCT), the first full-scale interferometric detector based on these approaches. For these aspects, this second generation detector will be the forerunner of third generation interferometers such as ET, therefore a collaboration between the two scientific collaborations has been established.
My experimental work is focused on the suppression of these low noise sources, so that this thesis is structured in two parallel fields of research: the seismic characterization of a potential site for the construction of the Einstein Telescope, and the development, calibration and test of a cryogenic vertical accelerometer, which can be used as a position control device, analogously to those used in the actual room-temperature superattenuator of Virgo, but also to check the vibrations introduced by the cryogenic apparatus, as I did with the measurements I performed on the cryostats of KAGRA, presented at the end of this thesis.
The scheme of this thesis is subdivided in three main parts: in the first part I introduce the foundations of the gravitational astronomy, from the theory and the astrophysical sources to the experiments which will lead to the gravitational observations; in the second part I discuss the theory of low frequency noise sources and their suppression; in the third part I present the experimental work I performed in this context.
Every part is composed of two chapters, structured as follows.
In the first chapter I describe the derivation of gravitational waves from the Einstein's field equations, discussing their properties and the astrophysical and cosmological sources, especially those whose emission is expected at low frequencies.
In the second chapter I describe the direct interferometric detection of gravitational waves and the main noise sources which limit the sensitivity, concluding with an overview of present and future detectors.
In the third chapter I discuss the main features of the seismic and Newtonian noises, and the strategies necessary to suppress them, especially in third generation detectors.
In the fourth chapter I discuss the theory of thermal noise, from the ideal case of the damped harmonic oscillator to the real dissipative mechanical systems and optical components of the interferometer.
In the fifth chapter I present my experimental work on the long-period characterization of the Sos Enattos site in Sardinia (proposed for hosting the Einstein Telescope), from the construction and instrumentation of an underground array of sensors to the analysis of seismic and meteorological data collected in one year of observations.
Finally, in the sixth chapter I present my experimental work on the development of a cryogenic vertical accelerometer, from the designing to the cryogenic calibration and tests at T=20 K. In this chapter I also present the results of the implementation of this device into the cryostats dedicated to the test masses of KAGRA, where I verified the operations of the accelerometer at T=8 K and I measured the vibrations of the inner radiation shield of the cryostats. These measurements led to a first experimental estimate of the additional vibrational noise which will be injected by the cryogenic refrigerators to the detector test masses.
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Ghosh, S. K. "Experimental and Computational Studies on Cryogenic Turboexpander." Thesis, 2008. http://ethesis.nitrkl.ac.in/7/1/sghosh-sarangi.pdf.
Full textAbstract:
The expansion turbine constitutes the most critical component of a large number of
cryogenic process plants – air separation units, helium and hydrogen liquefiers, and low
temperature refrigerators. A medium or large cryogenic system needs many components,
compressor, heat exchanger, expansion turbine, instrumentation, vacuum vessel etc. At present
most of these process plants operate at medium or low pressure due to its inherent advantages.
A basic component which is essential for these processes is the turboexpander. The theory of
small turboexpanders and their design method are not fully standardised. Although several
companies around the world manufacture and sell turboexpanders, the technology is not
available in open literature. To address to this problem, a modest attempt has been made at NIT,
Rourkela to understand, standardise and document the design, fabrication and testing procedure
of cryogenic turboexpanders. The research programme has two major objectives –
⇒ A clear understanding of the thermodynamic scenario though modelling, that will help
in determination of blade profile, and prediction of its performance for a given speed
and size.
⇒ To build and record in open literature a complete turbine system.
8
Sarangi, S. K. "Experimental and Computational Studies on Oil Injected Twin-Screw Compressor." Thesis, 2006. http://ethesis.nitrkl.ac.in/110/1/seshiah.pdf.
Full textAbstract:
Gas compressors are mechanical devices used for raising the pressure of gas or vapour either by lowering its volume (as in the case of positive displacement machines) or by imparting to it a high kinetic energy which is converted into pressure in a diffuser (as in the case of centrifugal machines). The classification and use of compressors are described in the next section The selection of compressors for different applications is a crucial issue in the process industry. It is usually the most expensive piece of equipment and has dominant influence on cycle efficiency. The common types of compressors used in industry are reciprocating, twin screw, single screw, centrifugal, scroll and rotary vane. Compressor manufacturers are used to having a large market potential. Probably all types of compressors can be improved over what is available in the market today; but the potential return must justify the expense of research and development to achieve the improvement The twin screw compres...
9
Patnaik, Kishore Chandrasekhar, and Manish Soni. "3-D Solid Modeling of Screw and Scroll Compressors Including Animation." Thesis, 2007. http://ethesis.nitrkl.ac.in/117/1/10303069.pdf.
Full textAbstract:
The objective of the work is to do solid modeling of the screw and the scroll compressors using 3-D solid modeling software. Screw compressor rotors are available in various profiles out of which “N” profile with 3/5 configurations is taken for the modeling and fabrication purpose.
Scroll compressor consists of spiral vanes out of which one remains stationary and the other one wobbles around an axis so as to create a continuously decreasing volume between the two vanes. Solid modeling of screw and scroll compressors is achieved using the modeling software Autodesk Inventor Professional 11. The output of the software modeling is stored in various file formats out of which *.stl (STEREO LITHOGRAPHY) format is transferred to the Rapid Prototyping machine Z-Print 310 plus available at Department of Mechanical Engineering, NIT Rourkela . Then the rotors were fabricated using rapid prototyping technology which were afterwards planned to cast in metal. When conventional methods of preparing moulds did not work, rapid prototyping was again used to make moulds. Solid modeling of moulds was done to create a cavity of rotor’s shape in a cylindrical mould of adequate wall thickness.
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Dash, S. M. "Study of Cryogenic Cycles with Aspen-Hysys Simulations." Thesis, 2009. http://ethesis.nitrkl.ac.in/241/1/10503073.pdf.
Full textAbstract:
Computer-aided process design programs, often referred to as process simulators, flow sheet simulators, or flow sheeting packages, are widely used in process design. Aspen
HYSYS by Aspen Technology is one of the major process simulators that are widely used in chemical and thermodynamic process industries today. It specializes on steadystate analysis. System simulation is the calculation of operating variables such as pressure, temperature and flow rates of energy and fluids in a thermal system operating in a steady state. The equations for performance characteristics of the components and thermodynamic properties along with energy and mass balance form a set of
simultaneous equations relating the operating variables. The mathematical description of system simulation is that of solving these set of simultaneous equations which may be
non-linear in nature.
Cryogenics is the branch of engineering that is applied to very low temperature refrigeration applications such as in liquefaction of gases and in the study of physical phenomenon at temperature of absolute zero. The various cryogenic cycles as LINDE cycle, CLAUDE cycle etc govern the liquefaction of various industrial gases as Nitrogen,
Helium etc. The following work aims to simulate the cryogenic cycles with the help of the simulation tool ASPEN HYSYS where all calculations are done at steady state and the results hence obtained.
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Pradhan, Bidhan Kumar. "Computational Fluid Dynamics Analysis of Flow in High Speed Turbine using Fluent." Thesis, 2009. http://ethesis.nitrkl.ac.in/244/1/10503054.PDF.
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This project deals with the computational fluid dynamics analysis of flow in high speed turbine. This involves with the three dimensional analysis of flow through of a high turbine having radial inlet and axial outlet. The software used for this purpose are GAMBIT and FLUENT. The 3 D model of the parts of the turbine are made by GAMBIT and analysis are to be carried out by FLUENT. The models are first generated using the data and then are meshed and then various velocity and pressure contours are to be drawn and graphed in this paper to analyze the flow through the cryogenic turbine. Various graphs indicating the variation of velocity, pressure and temperature along the stream length of the turbine are given.
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Rawat, Vivek Kumar. "Theoretical and Experimental Studies on Pulse Tube Refrigerator." Thesis, 2009. http://ethesis.nitrkl.ac.in/287/1/PTR_thesis.pdf.
Full textAbstract:
The absence of moving components at low temperature end gives the pulse tube refrigerator (PTR) a great leverage over other cryo-coolers like Stirling and GM refrigerators that are conventionally in use for several decades. PTR has greater reliability; no electric motors to cause electromagnetic interference, no sources of mechanical vibration in the cold head and no clearance seal between piston and cylinder. Moreover, it is a relatively low cost device with a simple yet compact design.
The objectives of the present work are to 1) understand the basic phenomena responsible for the production of cold effect with the help of simple theoretical models based on ideal behavior of gases and to 2) test a single stage GM type pulse tube refrigerator present in the cryogenics lab of Mechanical Engineering Department of NIT Rourkela. Experimental studies consist of cooling behavior of the refrigeration system and suggesting modifications to improve the performance of the PTR.
13
Dewatwal, Jainender. "Design of Compact Plate Fine Heat Exchanger." Thesis, 2009. http://ethesis.nitrkl.ac.in/297/1/DESIGN_OF_COMPACT_PLATE_FIN_HEAT_EXCHANGER2.pdf.
Full textAbstract:
Plate fin heat exchangers, because of their compactness, low weight and high effectiveness are widely used in aerospace and cryogenic applications. This device is made of a stack of corrugated fins alternating with nearly equal number of flat separators known as parting sheets, bonded together to form a monolithic block. Appropriate headers are welded to provide the necessary interface with the inlet and the exit streams. While aluminum is the most commonly used material, stainless steel construction is employed in high pressure and high temperature applications.
The performance of a plate fin heat exchanger is determined, among other things, by the geometry of the fins. The most common fin configurations are - (1) plain (straight and uninterrupted) rectangular or trapezoidal fins (2) uninterrupted wavy fins and (3) interrupted fins such as offset strip, louver and perforated fins. The interrupted surfaces provide greater heat transfer at the cost of higher flow impedance.
Here I have designed rectangular offset plate fin heat exchanger. I have assumed some data and based on them I have designed heat exchanger . The flowing fluid in heat exchanger is liquid nitrogen and material of heat exchanger is Al. After designing the heat exchanger, rating is also necessary .
The heat transfer and flow friction characteristics of plate fin surfaces are presented in terms of the Colburn factor j and the Fanning friction factor f vs. Reynolds number Re, the relationships being different for different surfaces.
The laminar flow model under predicts j and f values at high Reynolds number, while the 2-Layer k-e turbulence model over predicts the data throughout the range of interest. Because most industrial heat exchangers operate with Re less than 3000, and because the j and f data predicted by the laminar and the 2-layer k-e turbulence model differ little from each other at low Reynolds numbers, we have used the laminar flow model up to Reynolds number of 10,000, which is considered to be the limit for plate fin heat exchangers operating with gases. Velocity, pressure and temperature fields have been computed and j and f factors determined over appropriate range of Reynolds number and geometric dimensions.
14
Prasad, Shailesh. "Simulation of Nitrogen Liquefication Cycles." Thesis, 2009. http://ethesis.nitrkl.ac.in/1402/1/shailesh_final_thesis.pdf.
Full textAbstract:
System simulation is the calculation of operating variables such as pressure, temperature and flow rates of energy and fluids in a thermal system operating in a steady state. The equations for performance characteristics of the components and thermodynamic properties along with energy and mass balance form a set of simultaneous equations relating the operating variables. The mathematical description of system simulation is that of solving these set of simultaneous equations which may be non-linear in nature. Simulation is not needed in design conditions because in the design process the Engineer probably chooses reasonable values of the operating variables and selects the components that correspond to operating variables.
Cryogenics is the branch of engineering that is applied to very low temperature refrigeration applications such as in liquefaction of gases and in the study of physical phenomenon at temperature of absolute zero. The various cryogenic cycles as Linde cycle, Claude’s cycle , Stirling cycle etc govern the liquefaction of various industrial gases as Nitrogen, Helium etc. We have the operating conditions and operating variables which can be solved numerically which is tedious. The following work aims to simulate the nitrogen liquefication cycles with the help of the simulation tool ASPEN HYSYS where all calculations are done at steady state and the results hence obtained.
15
Nayak, Asutosh. "Development of design software for Cryogenic Turbo Expander." Thesis, 2010. http://ethesis.nitrkl.ac.in/1641/1/thesis10603004.pdf.
Full textAbstract:
This thesis provides the complete designing procedures encapsulated in an object oriented programming. The software is written in C++codes and gives the detail design of each component of the cryogenic turbo expander. The design procedure is complied in a very systematic manner due to the work of various person in this typical region. The thesis begins with the introduction of a Turbo expander. It contains the literature review which states the work done by various person with passage of time. The anatomy of turbo expander provides the complete picture and the understanding basics of each parts which helps in knowing and analyzing various parameters associated. A systematic approach of calculation is mentioned with the draw of flowcharts and step wise algorithm.
The various chapters helps in designing codes for the design of cryogenic turbo-expander.The codes are effective and is very user friendly.
16
Sahoo, Somadutta. "Process design of cryogenic system using ASPENHYSYS simulation." Thesis, 2010. http://ethesis.nitrkl.ac.in/1650/1/final_thesis.pdf.
Full textAbstract:
The thermodynamic efficiency of any process is dependant upon following factors:
(a) The efficiency of independent components used.
(b) Operating condition i.e. variation of input parameter(like temperature, Pressure etc)
To improve the efficiency of any process, efficiency of component is fixed (it is dependant upon level of technology available and cost of equipment), thus we are left with optimizing operating condition which is under our control. This paper presents analysis of thermodynamic cycle
commonly used for liquefaction of Nitrogen (N2) under given set of operating condition and efficiencies. The liquefying temperature of Nitrogen being 77.36K is taken into consideration.
The cycles considered are:
(a) Simple LINDE-HAMPSON cycle
(b) CLAUDE cycle
Computer-aided process design programs, often referred to as process simulators, flow sheet simulators, or flow sheeting packages, are widely used in process design. Aspen
HYSYS by Aspen Technology is one of the major process simulators that are widely used in chemical and thermodynamic process industries today. It specializes on steadystate analysis. System simulation is the calculation of operating variables such as pressure, temperature and
flow rates of energy and fluids in a thermal system operating in a steady state. The equations for performance characteristics of the components and thermodynamic properties along with energy and mass balance form a set of
simultaneous equations relating the operating variables. The mathematical description of system simulation is that of solving these set of simultaneous equations which may be
non-linear in nature.
Cryogenics is the branch of engineering that is applied to very low temperature refrigeration applications such as in liquefaction of gases and in the study of physical phenomenon at temperature of absolute zero. The various cryogenic cycles as LINDE cycle, CLAUDE cycle etc
govern the liquefaction of various industrial gases as Nitrogen,Helium etc. The following work aims to simulate the cryogenic cycles with the help of the simulation tool ASPEN HYSYS where all calculations are done at steady state and the results hence obtained.
17
Bishoyee, N. "3-D Modeling and Rapid Prototyping of a Cryogenic Liquefier." Thesis, 2010. http://ethesis.nitrkl.ac.in/1736/1/3-D_Modeling_and_Rapid_prototyping_of_a_cryogenic_liquefier.pdf.
Full textAbstract:
Our country is still dependent on imports for most of its needs in cryogenic refrigerators and liquefiers. These products are proprietary in nature which makes it very expensive for its cost and maintenance. With support from the Department of Atomic Energy, our institute has initiated a program on development and study of a nitrogen liquefier of intermediate capacity in the range of 10-50 liters/hr by using technologies already developed in our country. The process is based on a suitable modified Claude cycle which minimizes the number of heat exchangers and also takes care to accommodate the in house developed turbo expander. The thermodynamic parameters (temperature, pressure, pinch point temperature) and rate of mass flow are evaluated to obtain the required designing specifications for each component. The main objective of this report is to model all the components that are to be placed inside the vessel using CAD software and make an assembly so that all the components are placed properly inside the vessel and then connect pipes between components according to the design specifications.
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Roy, Bibartan. "Numerical Analysis in a Thermoacoustic Cryocooler." Thesis, 2010. http://ethesis.nitrkl.ac.in/1857/1/bebo.pdf.
Full textAbstract:
This project deals with the computational fluid dynamics analysis of flow in a Thermoacoustic Cryocooler showing the comparison between a straight tube and a curved tube resonator. This involves with the two dimensional analysis of flow through of Cryocooler having radial inlet and axial outlet. The software used for this purpose are GAMBIT and FLUENT. The 2 D model of the parts of the Cryocooler are made by GAMBIT and analysis are to be carried out by FLUENT. The models are first generated using the data and then are meshed and then various velocity and pressure contours are to be drawn and graphed in this paper to analyze the flow through the cryocooler. Various graphs indicating the variation of velocity, pressure and temperature along the stream length of the turbine are given.
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Maiti, Trijit Kumar. "Development and Study of a Helium Purifier based on Low Temperature High Pressure Adsorption of Impurities." Thesis, 2011. http://ethesis.nitrkl.ac.in/2736/2/60603001.pdf.
Full textAbstract:
Most helium liquefiers today operate on modified Claude cycle with at least two high speed turbo expanders. Impure gas cannot be fed to these liquefiers as air impurities solidify at low temperature, and damage the turbo expanders and choke the tubes. Therefore, a helium purifier is an integral part of any cryogenic establishment to conserve helium gas by providing Grade 4.5 helium or 99.995% helium to the liquefier after separating air contaminants from impure helium. At present, research and academic centres in India, import helium purifiers which are very expensive in terms of foreign exchange. National Institute of Technology, Rourkela, has taken up a project for development of cryosorption based helium purifier funded by the Board of Research in Nuclear Sciences, Mumbai, which primarily aims at developing helium purifier and studying its performance. This dissertation details the design, fabrication and performance analysis of a prototype helium purifier. The purifier is based on the principle of cryocondensation of moisture and air impurities on heat exchangers at appropriate temperatures and cryosorption on activated charcoal to yield Grade 4.5 helium from 60% pure helium at LN2 temperature. The purifier has been designed for 6 hours nonstop operation with throughput of 20 nm3/hr and delivery of pure helium at a pressure of 150 bar(a), which is ensured by a reciprocating compressor. The vital component, adsorber columns, was packed with Indian manufactured granular coconut shell activated charcoal in 50 NB Sch 80 SS 316L pipe. Other major components include moisture collector vessel, liquid air separator vessel, three heat exchangers, snow filter, gas bag, cylinder manifold and superinsulated LN2 vessel housing all cryogenic components of purifier. Helium gas bag, made of textile reinforced rubber has been successfully developed. All the components were fabricated, assembled and commissioned at NIT, Rourkela. Conditioning of the system was carried out by heating with six 1000 W tubular heaters, followed by evacuation. The system was back filled with Grade 4.5 helium. Experiment was carried out for one session by feeding the purifier with 5% dry nitrogen contaminant in helium as input gas, and four samples of purified gas were collected in sample cylinders at different intervals. Sample analysis by Linde Multi Component Detector reveals that the total impurity, consisting of nitrogen, oxygen and moisture, is less than 5 ppm by volume, thus making the purified gas much better than Grade 4.5 helium.
20
Bhushan, Jitendra. "Helium Purification by Gas Adsorption method." Thesis, 2011. http://ethesis.nitrkl.ac.in/2933/1/thesis_jeet__Autosaved_1.pdf.
Full textAbstract:
In a cryogenic establishment, helium gas is an expensive consumable. Conservation of helium is important not only for saving on cost, but also for ensuring supply at the time of need. During laboratory experiment, helium gas is often contaminated with air impurities (nitrogen, oxygen, argon, moisture etc.) which must be removed before the spent gas is reused for liquefaction. Therefore, a helium purifier is an integral part of any cryogenic establishment to conserve helium gas by providing grade 4.5 helium or 99.995% pure helium to liquefier after separating air contaminants from impure helium. The helium purification is based on two principles, one is cryocondensation of moisture and air impurities, on heat exchangers at appropriate temperature and other one is cryosorption on activated charcoal to yield grade 4.5 helium from 60% pure helium at LN¬2 temperature and at high pressure of about 150 bar. The purifier has been designed for purifying impure helium upto 40% of impurity by running 6 hours non-stop operation with the mass flow rate of 20 nm3/hr and delivery of impure helium to purifier at a pressure of 150 bar(a) ,which is ensured by a 3-stage reciprocating compressor. In the helium purifier for cryocondensation and cryosorption process the components are moisture collector vessel, three heat exchangers, liquid air separator vessel and adsorber columns. Other major components are gas bag, compressor, LN2 vessel and cylinder manifold. Where, all cryogenic components are housed in Superinsulated LN2 vessel. Purification of helium involved two phase, one is regeneration phase and second is purification phase. For complete removal of moisture from charcoal beds regeneration should be done before purification, by heating and evacuation with purging of pure helium to whole system. And in purification phase we have taken 95% of pure helium and 5% of impurity i.e. dry nitrogen contaminants. Experiment was carried out for one session and four samples are taken in sample cylinder at different interval of time. Sample analysis by Linde Multi Component Detector reveals that the total impurity, consisting of nitrogen, oxygen and moisture is less than 5 ppm be volume, thus making the purified gas much better than grade 4.5 helium.
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Akash, Pandey. "Performance analysis of a compact heat exchanger." Thesis, 2011. http://ethesis.nitrkl.ac.in/2936/1/final_thesis_A.pdf.
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Compact heat exchangers are one of the most critical components of many cryogenic components; they are characterized by a high heat transfer surface area per unit volume of the exchanger. The heat exchangers having surface area density (β) greater than 700 m2/m3 in either one or more sides of two-stream or multi stream heat exchanger is called as a compact heat exchanger. Plate fin heat exchanger is a type of compact heat exchanger which is widely used in automobiles, cryogenics, space applications and chemical industries. The plate fin heat exchangers are mostly used for the nitrogen liquefiers, so they need to be highly efficient because no liquid nitrogen is produced, if the effectiveness of heat exchanger is less than 87%. So it becomes necessary to test the effectiveness of these heat exchangers before putting them in to operation.
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Alur, Sidramappa. "Experimental studies on plate fin heat exchangers." Thesis, 2012. http://ethesis.nitrkl.ac.in/4426/1/Alur_Final_Thesis.pdf.
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Heat exchangers used in cryogenic applications need to have very high effectiveness to preserve the refrigerating effect produced. Normally the heat exchangers used in cryogenic refrigerators and liquefiers have effectiveness of the order of 0.95 or higher. If the effectiveness of the heat exchangers falls below the design value, there may not be any liquid yield. Plate fin heat exchangers, because of their compactness, low weight and high effectiveness, are widely used in aerospace and cryogenic applications. Such heat exchangers have closely spaced fins and offer narrow and intricate passages for the fluid flow which often leads to significant pressure drop. The stringent requirement of high effectiveness in cryogenic refrigerators and liquefiers and high pressure drop occurring in plate fin heat exchangers make it necessary to test the heat exchanger before putting into operation in a liquefier.Plate fin heat exchanger (PFHE) is a type of compact exchanger that consists of a stack of alternate flat plates called parting sheets and corrugated fins, both being brazed together as a block. Streams exchange heat by flowing along the passages made by the fins between the parting sheets. Separating plates act as the primary heat transfer surfaces and the appendages known as fins act as the secondary heat transfer surfaces intimately bonded to the primary surface. Aluminum is the most commonly used material and stainless steel is employed in high pressure and high temperature applications.
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Kumar, Ravindra. "CFD Simulation of a Small Stirling Cryocooler." Thesis, 2013. http://ethesis.nitrkl.ac.in/4742/1/109ME0380.pdf.
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The application of cryocoolers has advanced in various fields of modern day applications because of adequate refrigeration at specified temperature with low power input, high reliability, long lifetime, and light weight. The demand of Stirling cryocoolers has increased due to the ineffectiveness of Rankine cooling systems at lower temperatures and with the advancement in applications of Stirling cryocoolers, several simulations of such cryocoolers were also developed. These simulations saved a lot of time and money as it could provide an accurate analysis of the performance of the cryocooler before actually manufacturing it. At present, design issues of mini cryocooers are given more serious consideration for its applications in various fields. There are large and diverse applications of cryogenic technology and very often a new application is added to the list. Here, in this project, an attempt has been made to formulate a CFD simulation of a stirling cryocooler. This project deals with a new type of numerical computational fluid dynamic (CFD) approach of making more realistic to the porous media inside the regenerator of a stirling refrigerator. The available commercial software package FLUENT for solving Computational fluid dynamics (CFD) has capable of define a porous media and solve the governing equation for this region. A detailed analysis has been done of the simulation of the cryocooler in the results and discussion section.
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B, Aarif. "Simulation of 1610 Helium Liquefier." Thesis, 2013. http://ethesis.nitrkl.ac.in/5256/1/211ME3184.pdf.
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Cryogenics is generally described as the science and technology of producing low temperature environment. The various cryogenic cycles such as Collins cycle, Linde cycle etc. govern the liquefaction of various industrial gases, namely, helium, nitrogen etc. In this project work, helium liquefier has been simulated with the help of the simulation tool Aspen hysys and simulation work is carried out at steady state using MBWR (Modified Benedict–Webb–Rubin) equation of state in order to get the desired output. The present analysis is carried out to assess the role of different component efficiencies in predicting overall system efficiency at the design and off design conditions. In this analysis, the temperature is assumed to evaluate the expander efficiency and heat exchanger effectiveness in order to optimize the plant efficiency. The evaluated thermodynamic parameters are obtained and the optimum mass fraction through expander for maximum liquid yield is calculated.
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Das, Harish Chandra. "Intelligent Diagnosis and Smart Detection of Crack in a Structure from its Vibration Signatures." Thesis, 2009. http://ethesis.nitrkl.ac.in/5488/1/Harish_507ME008.pdf.
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In recent years, there has been a growing interest in the development of structural health monitoring for vibrating structures, especially crack detection methodologies and on-line diagnostic techniques. In the current research, methodologies have been developed for damage detection of a cracked cantilever beam using analytical, fuzzy logic, neural network and fuzzy neuro techniques. The presence of a crack in a structural member introduces a local flexibility that affects its dynamic response. For finding out the deviation in the vibrating signatures of the cracked cantilever beam the local stiffness matrices are taken into account. Theoretical analyses have been carried out to calculate the natural frequencies and mode shapes of the cracked cantilever beam using local stiffness matrices. Strain energy release rate has been used for calculating the local stiffness of the beam. The fuzzy inference system has been designed using the first three relative natural frequencies and mode shapes as input parameters. The output from the fuzzy controller is relative crack location and relative crack depth. Several fuzzy rules have been developed using the vibration signatures of the cantilever beam. A Neural Network technique using multi layered back propagation algorithm has been developed for damage assessment using the first three relative natural frequencies and mode shapes as input parameters and relative crack location and relative crack depth as output parameters. Several training patterns are derived for designing the Neural Network. A hybrid fuzzy-neuro intelligent system has been formulated for fault identification.
The fuzzy controller is designed with six input parameters and two output parameters. The input parameters to the fuzzy system are relative deviation of first three natural frequencies and first three mode shapes. The output parameters of the fuzzy system are initial relative crack depth and initial relative crack location. The input parameters to the neural controller are relative deviation of first three natural frequencies and first three mode shapes along with the interim outputs of fuzzy controller. The output parameters of the fuzzy-neuro system are final relative crack depth and final relative crack location. A series of fuzzy rules and training patterns are derived for the fuzzy and neural system respectively to predict the final crack location and final crack depth.To diagnose the crack in the vibrating structure multiple adaptive neuro-fuzzy inference system (MANFIS) methodology has been applied. The final outputs of the MANFIS are relative crack depth and relative crack location. Several hundred fuzzy rules and neural network training patterns are derived using natural frequencies, mode shapes, crack depths and crack locations.
The proposed research work aims to broaden the development in the area of fault detection of dynamically vibrating structures. This research also addresses the accuracy for detection of crack location and depth with considerably low computational time. The objective of the research is related to design of an intelligent controller for prediction of damage location and severity in a uniform cracked cantilever beam using AI techniques (i.e. Fuzzy, neural, adaptive neuro-fuzzy and Manfis).
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Sheelvardhan, K. "Analysis and simulation of superconducting magnetic energy storage system." Thesis, 2014. http://ethesis.nitrkl.ac.in/5576/1/e-thesis_41.pdf.
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Subject field of the energy charging, storing and discharging characteristics of the Superconducting Magnetic Energy Storage system have been theoretically studied in the time to make an integrated mathematical model and the simulation model to analyses the characteristics of charging and discharging practically in Matlab. In this paper a novel controller is designed for controlling the Magnetic Energy storage system ensure (a) fast return of energy to the superconducting coil under constant current mode and (b) a constant and sinusoidal input supply current irrespective of the varying load demand with and without harmonics. A special feature of this controller is its ability to smoothly charge the superconducting coil using constant current charging so that it can be ready for the next discharging operation as soon as possible. Matlab, Simulink is done under this paper with Matlab coding for generating the graph. The results suggest that the Theoretical and Simulink graph is approximately similar and with is the more simple Controller is designed for the Energy Discharging.
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Jadhav, N. "Analysis of cooling capacity and optimization of compressor outlet pressure for KW class helium refrigerator/liquefier." Thesis, 2014. http://ethesis.nitrkl.ac.in/5582/1/E-45.pdf.
Full textAbstract:
The main components of a helium liquefier determines the performance for a given compressor flow rate are Turbine, HE and JT valve. Turbine and JT valve produces cooling effect by isentropic and isenthalpic expansion. For each configuration main components can have different operating process parameters leading to different performance of HRL. This project involves the analysis and optimization of compressor outlet pressure for a given configuration. JT valve is at the lowest temperature to get the highest liquefaction which depends on the performance of other components so optimization of process parameter of JT valve is not considered here. One of the different cycle configurations is analyzed and is often used in HRL. This configuration, planned to use for the indigenous helium plant, has 3 turbines and 8 HE which produces liquid helium at 4.5 K. 1st and 2nd turbines operates at warmer temperature compared to 3rd and those are connected in series. Helium stream coming out of the 1st turbine passes to HE which will reduce its temperature before entering the 2nd turbine. Helium flow rate supplied by the compressor system is 210 g/s at 14 bar and 310 k. Effects of compressor flow rate and pressure on the cooling capacity of the plant have been analyzed. A part of this flow rate passes through a 1st and 2nd turbine for isentropic expansion to 1.2 bar and then this low pressure helium stream comes back to compressor suction through different HE to transfer cooling effect to the hot stream coming from the compressor. 3rd turbine will expand to 4 bar and this stream further passes through a HE before entering the JT valve for liquid helium production. This work involves different practical factors and in efficiencies of main components. The analysis result for flow of 140 g/s at 14 bars is further compared with the performance of existing helium plant at IPR which has same compressor flow parameter. The results are also compared with that of the aspen tech software.
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Senthooran, Ravikumar. "Computational Fluid Flow analysis in Cryogenic Turbo expander." Thesis, 2014. http://ethesis.nitrkl.ac.in/5765/1/110ME0647-7.pdf.
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Cryogenic turbo expander is one of the components used in cryogenic plant to achieve low temperature refrigeration. Basic components in cryogenic Turbo expander are Turbine wheel, brake Compressor, shaft, nozzle, Thrust bearing, Journal Bearing etc. In expansion Turbine Temperature of gases decreases due to expansion and produces coldest level of Refrigeration. This project is all about Computational Fluid flow analysis of high speed rotating turbine. This involves with the three dimensional analysis of flow through a radial expansion turbine, using nitrogen as flowing fluid. Cfd packages, Bladegen, Turbogrid and CFX are used to carry out the analysis. Bladegen is used to create the model of turbine using available data of hub, shroud and blade profile. Turbogrid is used to mesh the model. CFX-Pre is used to define the physical parameters of the flow through the Turbo expander. CFX-Post is used for examining and analyzing results. Using these results variation of different thermodynamic properties like Temperature, Pressure, density, velocity etc inside the turbine can be seen. Several graphs are plotted showing the variation of velocity, pressure, temperature, entropy and Mach number along streamline and span wise to analyze the flow through cryogenic turbine
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kumar, V. B. "Control of a Superconducting Magnetic Energy Storage unit for Synchronous Generator Damping Enhancement." Thesis, 2014. http://ethesis.nitrkl.ac.in/5776/1/212ME5407-1.pdf.
Full textAbstract:
In power system, oscillations may occur due to load change or system fault which creates unsynchronized and undamped signals and creates instability in the system. So to enhance dynamic stability of the system, a control mechanism is constructed for Superconducting magnetic energy storage (SMES) unit to enhance the damping of the power system. Proportional Integral (PI) controller is utilized to improve damping of oscillation of a synchronous generator connected to an infinite bus. Eigen values of system are found using matlab which helps in minimizing the oscillations caused by disturbances and enhances damping. PI controller parameters are found by using pole assignment technique Response curves are generated in Matlab to compare the difference between the damping of oscillations for synchronous generators without PI controller and with PI controller with SMES
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Behera, Adarsh Kumar. "Design and Analysis of Internal 20 K Helium Gas Purification System for the kW Class Helium Refrigerator/Liquefier." Thesis, 2014. http://ethesis.nitrkl.ac.in/5874/1/212ME5403-4.pdf.
Full textAbstract:
The Helium refrigerator/Liquefier (HRL) is normally operated with helium gas having purity better than 99.999% by volume which is equivalent to having 10PPM (parts per million) impure gas in helium gas. Although sufficient precautions and impurity removal procedures are used, still, in the process of gas transfer or due to some other processes before reaching to liquefaction, impurity level sometimes can go as high as 500 PPM averaging to about 100 PPM. These impurities mainly consists of gases present in the air, like N2,O2,Ar,H2,H2O,CO,CO2 and the traces of Ne. Hydrocarbons of the lubricating oil can also be sources of H2.These gases condense at significantly higher temperature compared to LHe (4.5K).If such high level of impurity enters the process equipment placed inside the cold box of HRL, then it can condense and choke the pipelines and the valves leading to large pressure drop and inefficient liquefaction process.20k to remove H2.This project is about the design and analysis of 20K purification system to be used for the planned indigenous helium plant of equivalent cooling capacity ~2 kW at 4.5 K. The impurity level of H2 in helium gas stream is expected to about 10 to 100 PPM. Activated charcoals are to be used to adsorb impure gases from cold helium gas at 20K and 80K at ~14 bar. The nominal flow rate of helium, entering the 20 K purifier system, is 100 gm/sec.Activated charcoal is used for adsorption process.At the outlet of the 20K purifier, the total impurity should be 1PPM. At the downstream of the adsorber bed, fine filters of 30 micron pore size should be placed to trap the charcoal dust which can come sometime through the helium stream. This purifier will be a part of the indigenous helium development project. In this context, this work also involves the manufacturing, assembly, test, repair aspect of these purifiers.
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Kumar, Ashish. "Design and Development of Cryocooler Based Liquid Nitrogen Plant." Thesis, 2014. http://ethesis.nitrkl.ac.in/5900/1/212ME5445-2.pdf.
Full textAbstract:
The advantage of cryocooler is the small size of its cold head due to this it can be mounted on top of a Dewar, thus reducing overall size of the liquefier setup making it possible to use it in demanding sites and laboratories where the consumption of liquid nitrogen is not in higher quantities. So the dewar which is mostly used to store liquid cryogen, here is used for production and storage purposes. A cryocooler based Nitrogen liquefaction system was designed and developed which can be an ideal solution to the liquid nitrogen usage in laboratories. This setup uses a Cryomech Single stage Gifford-Mcmahon cryocooler to provide cooling and condensation of nitrogen at 80 K with the refrigeration capacity of 266 W (Rated) at 80K and a dewar specially fabricated with wider neck than usual dewar to accommodate cold head. The Gifford-Mcmahon cryocooler consist of compressor package, Helium Flex lines and cold head which is the heart and soul of this setup. The cold head is mounted into the top of the dewar and it extends down into the neck of the dewar for the purpose of cooling the nitrogen entering the dewar to 80K (-193ºC) at 0.5 bar gauge pressure which is the operating pressure for this dewar. The nitrogen gas liquefies on contact with the cold head heat exchanger. The liquefied nitrogen drips off the heat exchanger down into the dewar. This process would typically lower the pressure inside the dewar, but the regulator allows more nitrogen gas to enter the dewar to maintain the pressure at the preset level. The flow rate of the nitrogen gas into the dewar is controlled by the rate of liquefaction inside the dewar. In the experimental dewar maximum liquefaction rate of 74 Ltr/day and in the main dewar liquefaction rate of 64 Ltr/day were achieved. The difference in liquefaction rate was due to the high radiation load coming on cryogen reservoir of main dewar.
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Penthia, Trilochan. "Design and modelling of vacuum experimental set-ups." Thesis, 2014. http://ethesis.nitrkl.ac.in/5917/1/212ME5328-12.pdf.
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This thesis deals with study, modelling and designing of some laboratory apparatus in Cryogenics Engineering and Vacuum Technology field. The project is totally educational oriented. Project's aim is to give a clear idea about vacuum technology and modelling of such vacuum experimental set-ups which can serve as the laboratory experiments for both undergraduate and post graduate students. This project work is broadly classified into three parts:-- (i) Study, selection techniques and designing of some vacuum components. (ii) Modelling and operation of vacuum experimental set-ups. (iii) Making bills of materials for the proposed experimental se-ups. The experiments to be done are namely; (i) Study & Calculation of pumping speed of diffusion pump. (ii) Study & Calculation of pumping speed of roots pump. (iii) Study & Calculation of pumping speed of vacuum ejector pump. (iv) Study & Calculation of pumping speed of cryopump. (v) Calibration of vacuum gauges using primary gauges. (vi) Study and calculation of boil-off rate & heat transfer characteristics of vacuum insulation. Design of various components is done like vacuum chambers, thickness and length of pipe lines etc. So many calculations are done like calculation of pumping speed & flow rate of rotary pump, diffusion pump, roots pump and cryopump. Also calculation of boil-off rate of LN2 in vacuum insulation experiments is carried out. Constant volume method and constant pressure methods are used for pumping speed calculation. Vacuum insulation is studied in three ways one is with plain vacuum, second is with powder vacuum and the third one is with multilayer insulation.
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Bhunya, D. K. "Simulation study of cryogenic air separation unit using Aspen Hysys at Rourkela steel plant." Thesis, 2014. http://ethesis.nitrkl.ac.in/5971/1/E-138.pdf.
Full textAbstract:
It’s been a few days now, requirement of Nitrogen, Oxygen and Argon increases day by day. Especially for a steel industry this three components are very essential for their steel production like decarburization, desulphurization, hydrogen removal, nitrogenation, argon, oxygen removal, metal cutting, welding, and cooling etc. Cryogenic air separation has the best impact to separate the air. Study and analyses of practical plant performance through computer aided programs has better and cost effective. Aspen Hysys by Aspen Technology is one of the major process simulators that are widely used in cryogenic, chemical and thermodynamic process industries today. In this work, the simulation study of cryogenic air separation unit (Rourkela steel plant, Odisha) is performed by using Aspen Hysys. The simulation study is based on both steady state and dynamic (high pressure column and low pressure column). The dynamic air separation unit has been designed based on PI controller. The plant efficiency, specific power consumption, product purity and behaviour of process parameter with respect to time and feed disturbance have been discussed.
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Mahapatra, Omshree. "Design Of 3-Stream(He-He-He) Plate-Fin Heat Exchanger For Helium Plant." Thesis, 2014. http://ethesis.nitrkl.ac.in/6002/1/212ME5408-4.pdf.
Full textAbstract:
Plasma Research belongs to a new generation of tokamaks with the major objective being steady state operation of advanced configuration plasma. Liquid helium plant is required for superconducting magnets. The effectiveness of the heat exchangers which is used in the helium plant should be close to 100%. For some cases, heat exchangers with effectiveness less than 90% can be a reason for failure of helium plant to produce liquid helium. To achieve such high effectiveness, it is necessary to use plate fin heat exchangers, which provides very high heat transfer surface area for heat exchange per unit volume (ratio greater than 700 m2/m3) of heat exchanger. Such heat exchangers also have benefit of low pressure drop of fluid flowing through it. The helium refrigerator and liquefier (HRL), planned for development at Institute for plasma research (IPR), will have eight main heat exchangers, 3 turbo expanders with Joule- Thomson expansion valves for achieving liquid helium production. The fourth exchanger, whose nominal operating temperature range is ~30 K to ~10 K, is the 3-stream type (He/He/He) plate fin heat exchanger. This 3-stream (He/He/He) heat exchanger will be installed inside a vacuum chamber having vacuum of about ¡¼10¡½^(-5) mbar. High effectiveness, compact volume and low pressure drop are main optimizing parameters for the design of this heat exchanger. This design work is a step towards the development of the indigenous liquid helium plant.
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P, S. Shihabudeen. "Design of rotary, turbo-molecular and cryo-sorption pumping systems for vacuum laboratory." Thesis, 2014. http://ethesis.nitrkl.ac.in/6037/1/212ME5329-23.pdf.
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This project deals with study, design, construction and installation of Vacuum laboratory apparatus including preparation of lab manual for Vacuum Laboratory which is being set up under Refrigeration and Cryogenic Engineering Centre in NIT Rourkela. The Vacuum laboratory, a part of first year M.Tech (Cryogenics and Vacuum Technology) curriculum in Mechanical department, consists of twelve experiments in which six experiments will be designed and installed under this project. The proposed laboratory will help both the graduate and under graduate students of our institute to conduct different experiments under vacuum environment. Two experiments using rotary pump [1] namely; Pumping speed measurement and conductance measurement of different piping analogy need to be set up. For which we designed a vacuum chamber [3] with suitable capacity first, decided pump down time allowable to get ultimate vacuum level of a rotary pump in accordance with the total lab hrs assigned to each sessions, and finally we calculated pumping speed [2] required for the pump. The same rotary pump set up will be used for conductance measurement too, but with different piping analogy. Conductance of each pipe is calculated using relations and are compared with experimental results in series and parallel connections. For high vacuum application a turbo-molecular pump [4] experimental set up is designed. Pumping speed calculation as well as leak detection test may be carried out in this set up. For roughing and backing, a suitable rotary pump is fitted with this pump. Since Mass spectroscopic leak detection [5] is most commonly used leak detection method in vacuum systems, we proposed one MSLD with turbo-molecular pump. Bill of material for the turbo pump is also prepared and handed over to department.
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Dhakarwal, Mukesh. "Development of ccr based variable temperature insert for cryogen free superconducting magnet system." Thesis, 2014. http://ethesis.nitrkl.ac.in/6100/1/212ME5325.pdf.
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Cryogen free magnet systems using close cycle refrigerator(CCR) is gaining more attention nowadays with continuously increase in advancement of performance and reliability of the close cycle refrigerator. In research lab and institutes, material characterisation is done which includes study for basic material science. As it is evident that sample properties depend on the sample space temperature, which require variation of magnetic field with variable sample temperature. Hence, the need for variable temperature insert for cryogen free magnet system came into existence. This thesis reports the design and fabrication of variable temperature insert for cryogen free magnet system with temperature variation from 4.2K to 300K and sample space of 25mm. The experimental set up comprises of GM cryocooler, vacuum jacket, thermal shield, heat exchangers, charcoal adsorber, sample bore and sample holder, buffer tank, scroll pump for circulation of gas. It also includes the manufacturing of three conduction-cooled (Helical coil) heat exchangers(HX) by using copper tube which are cooled with the help of the CCR. In this experimental set up, Thermal shield is connected with 1st stage of the CCR and maintained at temperature of 1st stage of the CCR i.e. at 30 K whereas two heat exchangers are connected on 1st and 2nd stage of cryocooler. The objective of this work is to develop a system to cool sample space from 300 K to 4.2 K. It can be achieved by the circulation of helium gas. The helium gas is cooled by the HX ,cooled by the CCR. It takes 15 hrs cool the helium gas to the desired temperature. Multiple test runs are done to test the stability of the system under fine controlled flow rate and system is working extremely well, Variable temperature insert(VTI) is successfully integrated with the cryogen free magnet system and experiment with variable temperature and varying magnetic field can be performed as the system is in fully working state.
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Kumar, M. "Phasor analysis of GM-type double Inlet pulse tube refrigerator." Thesis, 2014. http://ethesis.nitrkl.ac.in/6157/1/E-57.pdf.
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The simplicity and varied application of a pulse tube refrigerator has always gained the attention of many scientist and researchers towards itself. It is because of this very reason that various different types of pulse tube refrigerator has come up with time. A GM type double inlet pulse tube refrigerator (DIPTR) is one of the many configuration of the pulse tube that has come up with time. Although the configuration of a DIPTR seems to be quite simple but its working principle is a bit complicated. The aim of the present work is to study the working principle behind a DIPTR and develop a MATLAB code for the same and use it further to draw a phasor for the governing equation, so as to validate the output of the code developed. The MATLAB code and the phasor developed in this work is then used to develop a simplified design method for determining the dimension of the pulse tube of a DIPTR.
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Dutta, Shounak. "Modelling and analysis of resistive superconducting fault current limiter." Thesis, 2014. http://ethesis.nitrkl.ac.in/6333/1/E-50.pdf.
Full textAbstract:
Increase in the demand and consumption of electrical energy has led to increase in the system fault levels. Superconducting Fault-current limiters (SFCL) offer ideal performance in electrical power system. Superconducting Fault Current Limiters (SFCLs) are used in power system network to mitigate the overcurrent and its prominent effects. Nowadays, Coated Conductors (CCs) are widely used for novel design of SFCL for such applications. The thermal and electrical behaviors of different configurations of SFCL in the presence of over-critical current are studied in detail to master its performance in a power grid. An algorithm to solve the differential equations characterizing the superconductingmaterial is developed using the Runge-Kutta method. In this report, comparative study on the operational characteristics of Resistive-SFCL based on BSSCO and YBCO Coated Conductors under fault condition is analyzed for an 110KV/9KA power system. Also Electro-thermal Model of Coated Conductor is implemented in MATLAB software. The developed models accurately predicted the current-time waveforms achievable with the limiters for an improved current limiting behavior during fault condition and even the restraining the conditions upsetting the thermal stability of the SFCLs. To verify the effectiveness of the proposed Resistive-SFCL, several case studies of Coated Conductors have been carried out in MATLAB. The results show the choice of optimal configuration of CCs as SFCL which effectively improves the thermal stability and current limiting characteristics under fault condition in the network.
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Shrivastava, Raj. "HTS inductive energy controlled discharging circuit & its application in the design of UPS." Thesis, 2014. http://ethesis.nitrkl.ac.in/6466/1/E-47.pdf.
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High temperature superconducting magnet (HTS) inductive energy charging and discharging characteristics and its nature has been theoretically dealt in this report and its detailed analysis by specific models and graphs has been presented so as to portray light on the future advancement in this field with the design of UPS. All the design are done using SIMULINK/MATLAB and the charging and discharging characteristics shows the advantage of HTS. And, this simulation results will support the development of UPS (uninterruptible power source) using the SMES technology with substantial great advantages. Superconducting Magnetic Energy Storage is a novel technology that stores electricity from the grid within the magnetic field of a coil comprised of superconducting wires with near zero loss of energy. SMES is a grid enabling device that stores and release large quantities of power almost instantaneously. The organization is capable of releasing high levels of ability within a fraction of a cycle to replace sudden loss or dip in line power. Strategic injection of brief bursts of power can play a crucial part in maintaining grid reliability, especially with today increasingly congested power lines and the high penetration of renewable energy sources such as wind and solar. A typical SMES consists of two parts- cryogenically cooled superconducting coil and power conditioning system which are motionless and result in higher reliability than many other power storage devices. Ideally, once the superconductivity coil is charged, the current will not decay and the magnetic energy can be stored indefinitely.
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Kumar, Bathina siva. "Comparative Study among Different Cryoprobe Configuration for Effective Necrosis of Biological Tissue." Thesis, 2015. http://ethesis.nitrkl.ac.in/6760/1/comparative_kumar_2015.pdf.
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The complete necrosis of malignant biological tissue can be achieved, when the optimal parameters (generation of ice ball around the cryoprobe, ablation ratio, cooling power requirement) are known to the cryosurgeon. In this study the optimal parameters(volume of ice ball around the cryoprobe, ablation ratio, cooling power requirements)are predicted and compared to maximize the tissue necrosis. Surgical parameters like lethal zone, frozen zone and ablation ratio are studied for different placements of cryoprobes. The percentage increase in ice ball volume (obtained at the end of freezing cycle, i.e. 10 min considering with and without central cryoprobe configurations) decreases with increase in the number of offset cryoprobe at same opereating conditions. It was observed that with the increase in offset cryoprobes, there was no remarkable growth on ablation ratio at the end of freezing process. However, the less number of offset cryoprobes resulted in effective ablation during the early stage of freezing process.Also, the cooling power requirement increases with increase in the number of offset cryoprobes and also increases with decrease in cryoprobe temperature.
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Rout, Sachindra Kumar. "Design and Analysis of Pulse Tube Refrigerator." Thesis, 2015. http://ethesis.nitrkl.ac.in/6966/1/2015_Sachindra_Phd_511ME107.pdf.
Full textAbstract:
After decades of rapid development, the absence of moving parts in the cold head, low vibration, long lifetime and high reliability, pulse tube refrigerators are the most promising cryo-coolers. Because of these momentous advantages, they are widely used in Superconducting Quantum Interference Devices (SQUIDs), cooling of infrared sensors, low noise electronic amplifiers, missiles and military helicopters, superconducting magnets, liquefaction of gases, gamma ray spectrometers, liquefaction of gases, X-ray devices and high temperature superconductors etc. It has also got wide applications in preservation of live biological materials as well as in scientific equipment. It is essential to accurate modelling of the pulse tube cryocooler and predicts its performance, thereby arrive at optimum design. At the current stage of worldwide research, such accurate models are not readily available in open literature. Further, the complexity of the periodic flow in the PTR makes analysis difficult. Although different models are available to simulate pulse tube cryocoolers, the models have its limitations and also range of applicability. In order to accurately predict and improve the performance of the PTR system a reasonably thorough understanding of the thermos fluid- process in the system is required. One way to understand the processes is by numerically solving the continuum governing equations based on fundamental principles, without making arbitrary simplified assumptions. The recent availability of powerful computational fluid dynamics (CFD) software that is capable of rigorously modelling of transient and multidimensional flow and heat transfer process in complexgeometries provides a good opportunity for analysis of PTRs. Performance evaluation and parametric studies of an Inertance tube pulse tube refrigerator (ITPTR) and an orifice pulse tube refrigerator (OPTR) are carried out. The integrated model consists of individual models of the components, namely, the compressor, after cooler, regenerator, cold heat exchanger, pulse tube, warm heat exchanger, inertance tube or orifice, and the reservoir. In the first part of the study, the commercial CFD package, FLUENT is used for investigating the transport phenomenon inside the ITPTR. The local thermal equilibrium and thermal non-equilibrium of the gas and the matrix is taken into account for the modelling of porous zones and the results are compared. The focus of the second part of the study is to establish the most important geometrical dimension and operating parameters that contribute to the performance of ITPTR and OPTR. The numerical investigation procedure for these investigations is conducted according to the Response surface methodology (RSM) and the results are statistically evaluated using analysis of variance method. Finally a multi-objective evolutionary algorithm is used to optimize the parameters and for an optimized case the phasor diagram is discussed.
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Sahu, Hulash Ram. "Design of Auxiliary Passive Magnetic Bearing for Cryogenic Turboexpander." Thesis, 2015. http://ethesis.nitrkl.ac.in/7346/1/2015_Design_Sahu.pdf.
Full textAbstract:
In the modern time of industrialisation high performance, high precision, smooth operations are a very vital requirement for a machine system. Such a very essential system is turboexpander which is used in the several applications to provide very low-temperature cooling and refrigeration. Nowadays, turboexpander systems are using gas bearings to operate friction free, noiseless and for smooth operation. The main problem for these turboexpander systems is a heavy contact of rotor parts with the static parts i.e. thrust bearing surface at the time of start-up and shut-down of the machinery. The rotary system of the modern turboexpanders, after using gas bearings to support against radial as well as axial thrust are facing the wearing problem with the static parts at the time of start and stop. To avoid the problem, an auxiliary passive magnetic bearing is modelled by using Finite Element Method Magnetics (FEMM) that can suspend the rotor system without heavy contact with the lower thrust bearing surface during start-up and shut-down. This magnetic bearing has to levitate a designed rotary system of weight approximately 2.64 N, which consists a rotor, a brake compressor and a turbine wheel. This pair of magnet bearings is axially magnetised and can levitate the rotor at an appropriate distance. After the simulation of different bearing dimensions with two types of Neodymium (NdFeB) alloy magnet of Grade N42 and N52, it is found that the grade N52 gives better values of repulsive forces at same gap and dimensions as compared to grade N42. It is also important to know that N52 has lower operating temperature (70oC) as compared to N42 (80oC). So according to the operating conditions any of the above grades can be used as an auxiliary passive magnetic bearing.
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Rajpuriya, Vishnu. "Analysis of Solidification and Remelting of Water Over a Cryocooled Sphere Through Natural Convection." Thesis, 2015. http://ethesis.nitrkl.ac.in/7365/1/107.pdf.
Full textAbstract:
The solidification of water by using cryocooled metallic sphere is studied both experimentally and numerically. In this experiment, the cryocooled metallic solid sphere is dipped inside the tank full of water. The experiment is performed with a steel ball having different diameters. The numerical analysis is also done and the result is compared with experimental result; a good match is obtained. The results are presented in terms of thickness of ice formed, time required for solidification and time required for melting. The flow field and heat transfer characteristics showed an axisymmetric feature indicating the flow to be laminar. However, it has been observed that the convection effect plays a major role during the melting process which results in an uneven melting of ice over the sphere
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Biswal, Rasmikanti. "Conjugate Heat Transfer Analysis in Cryogenic Microchannel Heat Exchanger." Thesis, 2015. http://ethesis.nitrkl.ac.in/7401/1/2015_Conjugate_Biswal.pdf.
Full textAbstract:
Printed circuit heat exchanger (PCHE) is a highly integrated plate type compact heat exchanger and most important as well as a most critical component in the cryogenic application. Compact heat exchangers are characterized by area density (? = AHT / V) i.e. heat transfer area per unit volume of the heat exchanger. The area density of compact heat exchanger is =700m2/m3 where the area density of printed circuit heat exchanger is = 25000m2/m3. Printed circuit heat exchangers are highly compact compared to conventional heat exchangers. The hydraulic diameter is less than 1mm. Printed Circuit Heat Exchanger manufacturing process is followed by chemical etching and chemical bonding. Microchannel for fluid flow are constructed by chemical etching of the metal plates according to different configuration then plates are stacked alternately and assembled by diffusion bonding. Due to its compact size, high efficiency, large heat transfer area PCHE (microchannel heat exchanger) are used in cryogenic refrigeration and liquefaction systems. A counter flow rectangular microchannel (40 mm × 1.6 mm × 1.2 mm) printed circuit heat exchanger is designed and simulated using commercial ANSYS FLUENT. The performance is investigated numerically with helium at cryogenic temperature. The performance is affected by axial conduction at low Reynolds number (Re = 100). Because of length and viscous nature, the fluid flow through the channel is laminar and thermally fully developed. The Nussle number (Nu), flux, dimensionless fluid temperature and wall temperature, effectiveness are determined for different Reynolds number Reynolds number (Re = 100) with varying material i.e. wall to fluid thermal conductivity ratio (ksf = 141.58 - 5061.5). Axial conduction (?) is calculated by using Kroeger’s equation. Effectiveness is calculated to investigate the thermal performance of the microchannel heat exchanger.
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Mishra, Ashutosh. "Analysis and Optimization of Process Parameters of Heat Exchangers and Turbines for Helium Refrigerator/Liquefier." Thesis, 2015. http://ethesis.nitrkl.ac.in/7424/1/2015_MT_AMishra_213ME5449.pdf.
Full textAbstract:
A Helium liquefier and refrigerator is very vital component of many superconducting magnets, fusion devices, Tokamaks etc. So it is very important to optimize helium liquefier/refrigerator. This project work involves analysis and optimization of the process parameters (helium flow rate, pressure and temperature) for main components (8 different heat exchangers and 3 different turbo-expanders) of helium plant of refrigeration capacity 1 kW at 4.5 K. This is a part of the indigenous helium plant development work going on at IPR, Bhat, Gandhinagar, Gujrat. Nevertheless, this plant can be operated in mixed mode also as helium refrigerator-cum-liquefier (HRL), although it is optimized for refrigeration load. To optimize process of any helium refrigeration/liquefaction cycle, it is very important to consider one independent variable at a time and under valid assumptions, study and analyze its effect on the process. From the analysis, the optimized value of the concerned and considered process variable is selected. The main components of an HRL that affect process parameters are compressor, heat exchangers ,expansion engines and expansion valves .The present analysis is basically concerned with the parameters of the heat exchangers vis –a-vis expansion engines. In the present analysis mainly total compressor mass flow rate, fraction of total compressor mass flow diverted towards expansion engines (turbo expanders), inlet temperature to various expansion engine and heat exchangers are analyzed and optimized using steady state approach. The present study, analysis and optimization of the important process parameters is done taking logical assumptions and fulfilling important practical constraints that are explained in this report. The work involves: Study different thermodynamic configurations of HRL. Study the HRL, existing at IPR. Study different component working principle and design aspects also. Study and analyze different practical factors and inefficiencies of main components that can affect the performance of HRL. Find out different possible methods to analyze the given thermodynamic configuration to find liquefaction and refrigeration capacity. v Choose the best method from point-4 and make a computer code to analyze and get the HRL performance. Generate different graphical trends from analysis and optimization for variation of different process parameters of components. Find the optimum process parameters of main components.
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Mohapatra, Dhiren. "Design and Analysis of Aerostatic Bearings of Cryogenic Turbines for Helium Refrigerator/Liquefier." Thesis, 2015. http://ethesis.nitrkl.ac.in/7501/1/2015_Design_Mohapatra.pdf.
Full textAbstract:
Aerostatic bearings are generally used in the field of high speed applications. The Helium Refrigerator/Liquefier (HRL) needs turbines as expansion machines to produce cooling effect which is further used for production of liquid helium. Cryogenic turbines are significantly smaller in size compared to those for room temperature applications but rotational speed is very high, about few hundred thousands of rpm and hence these have contact less gas bearings or magnetic bearings. This project involves the design and analysis of the aerostatic bearings with horizontal shaft configuration. In the aerostatic bearings, pressurized helium gas is passed through the bearings. Based on this pressure and temperature and the rotational speed of the turbines, the shaft of the turbine rotates without contact with bearing wall and the leakage between process gas and bearing gas is minimum. For different normal and offnormal operations, speeds will be different and hence the flow parameters for bearing gas flow will be controlled via control valves and the bearing should be designed to provide such contactless rotation. In this study, a theoretical analysis is presented for the load capacity, stiffness, flow rate of aerostatic journal bearing and thrust bearing with pocketed orifice. Effects of orifice diameter, radial clearance, inlet pressure and outlet pressure on load capacity, mass flow rate and stiffness have been analyzed. Dynamic unbalances like whirling of the shaft have also been covered in this study. Design considerations for limiting dispersion effect, and to avoid pneumatic hammer has also been taken into account. Validation of the analysis has been done by using ANSYS CFX with the numerical results
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Sahu, Sudhanshu Shekhar. "Axial Back Conduction in Cryogenic Fluid Microtube." Thesis, 2015. http://ethesis.nitrkl.ac.in/7504/1/150.pdf.
Full textAbstract:
Cryogenic technology is now a rapidly progressing system which is used in different cooling processes because the behaviour of many physical materials changes beyond our expectations. For example copper behave normally as other materials for electrical conductivity but at the cryogenic temperature it behaves as superconductor. Actually there is no certain temperature from which the cryogenic temperature starts but according to the scientist below -1500C or 123 K cryogenic temperature starts. Also the time is to use products of compactness which is known as miniaturization. In the engineering background there are many researchers who have studied and developed the micro channels as the cooling process is very efficient because the surface area to volume ratio is very less. So it is now a keen interest to use cryogenic temperature in the micro channels. There are different gases present in our atmosphere which are used as cryogenic fluids, example Helium, Nitrogen, Oxygen, etc., as boiling points of these gases are below cryogenic temperature. The boiling point of liquid Nitrogen is 77.2 K and the freezing point is 63 K. In this present work cryogenic gas is intended to flow through a circular micro channel and a two dimensional numerical simulation is carried out for an internal convective laminar flow through the channel, subjected to constant wall heat flux to see the axial back conduction in the solid substrate of the tube which leads to conjugate heat transfer. Nitrogen gas is used as working fluid to flow through the microtube. Thermo-physical properties (e.g. density, viscosity, specific heat and thermal conductivity) of nitrogen gas change appreciably with the temperature, thus thermophysical properties function of temperature are used as UDF as described in numerical simulation chapter. The micro channel of 0.4 mm diameter and 60 mm length are kept constant and δsf (i.e. ratio of wall thickness (δs) to inner radius (δf)) is varied such as 1, 2, 3, 4 & 5 throughout the simulation. Other variable parameters are Reynold’s number varies as 100 & 500 and ksf (i.e. solid conductivity ratio to fluid conductivity ratio) varies from 22.07931 to 45980.71. In this work it is tried to find out most suitable material i.e. ks value as well as suitable wall thickness of the microtube i.e. δs value with the help of change in different parameters. After the completion of the numerical analysis the conclusions found are, (i) wall conductivity ratio and wall thickness ratio play dominant role in the effect of axial back conduction, (ii) there exist an optimum ksf value at which average Nusselt number (Nuavg) is maximum while other parameters are kept constant, (iii) at higher value of δsf, average Nusselt number becomes lower, (iv) Nuavg increases with increase in flow rate i.e. increasing value of Reynolds number.
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Kumar, Manoj. "Experimental Analysis of Solidification and Remelting of Brine Solution Over a Cryocooled Sphere." Thesis, 2015. http://ethesis.nitrkl.ac.in/7596/1/2015_EXPERIMENTAL_ANALYSIS_Kumar.pdf.
Full textAbstract:
The Solidification and remelting of brine solution having different concentration over a cryocooled steel sphere is studied experimentally. Liquid nitrogen is used to chill the sphere at cryogenic temperature up to 77 K. Experiments are conducted to show the variation in thickness of ice formation at the outer surface of cryocooled solid sphere for different concentrations, locations and time intervals. It was observed that ice formed on the outer periphery of cryocooled sphere is a function of NaCl concentration in the solution. As the concentration of solution increases, total time (solidification as well as melting) and thickness of ice is decreased. Melting pattern of ice is also reported for different concentrations.
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Sahoo, Mitravanu. "Experimental and Numerical Studies on Plate Fin Heat Exchanger." Thesis, 2015. http://ethesis.nitrkl.ac.in/7601/1/2015_EXPERIMENTAL_AND_NUMERICAL_Sahoo.pdf.
Full textAbstract:
In the cryogenics field, high effectiveness heat exchangers of the order of 0.96 or higher are widely used for preserving the refrigeration effect produced. So, there will be no liquid yield if the effectiveness falls below that of the design value. Due to high effectiveness, low weight & compactness, the compact heat exchangers have their extensive applications in the air-conditioning system, oil industries, food industries & in the process industries. The plate fin heat exchangers (PFHE) is a type of compact heat exchanger which is manufactured by brazing a stack of alternate plates (parting sheets) & corrugated fins together. The exchange of heat occurs by the streams through the fins. Generally, aluminium is used for manufacturing PFHE due to their high thermal conductivity & low cost. In the plate fin heat exchanger, the pressure drop is also measured along with the effectiveness. The increase in pressure gradient can be outweighed by decreasing the passage length so that an acceptable pressure drop can be achieved. There is enormous research is going on to make out the heat transfer phenomena & also to determine the dimensionless heat transfer coefficients those are the Colburn factor (j) and the friction factor (f). This thesis on the offset strip plate fin heat exchanger compares the effectiveness, overall thermal conductance & the pressure drop obtained from the experimental data with some correlations on plate fin heat exchanger i.e., Joshi-Webb correlation, Maiti-Sarangi correlation, Manglik-Bergles correlation and also with the numerically achieved data obtained by using CFD.
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Addala, Sandeep. "Design and Modeling of Vacuum Pumping Systems for Laboratory Scale Applications." Thesis, 2015. http://ethesis.nitrkl.ac.in/7622/1/2015_Design_Sandeep.pdf.
Full textAbstract:
Vacuum is a condition where the pressures are below atmosphere. Based on the pressures vacuum can be classified into low, medium, high and ultra high ranges. Vacuum finds its applications in many areas including industry, space research, food processing. One should have knowledge on the generation of vacuum to understand its effects. This project mainly focuses on the experimental setup of the vacuum pumps. The study, design, construction and installation of vacuum pumping systems viz. Vacuum chamber, Rotary pump, Roots pump was done. The working of rotary and roots pumps was studied and a list proper and necessary components and accessories was prepared. The methods to calculate the pumping speed of a pump at a pressure range were studied namely constant volume and constant pressure methods. The experiments were carried out and observations are plotted in a graph. The concepts of leak detection were also studied. Finally, the project helps in establishment of vacuum technology laboratory at NIT Rourkela, giving a practical approach to the students dealing with the Vacuum Technology to understand the vacuum process and research can be continued