Relevant bibliographies by topics / Natural circulation loop

Contents

  1. Journal articles
  2. Dissertations / Theses
  3. Books
  4. Book chapters
  5. Conference papers
  6. Reports

Academic literature on the topic 'Natural circulation loop'

Author: Grafiati
Published: 4 June 2021
Last updated: 10 March 2023

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Natural circulation loop.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Journal articles on the topic "Natural circulation loop"

1

Yang, Xingtuan, Yanfei Sun, Zhiyong Liu, and Shengyao Jiang. "Natural Circulation Characteristics of a Symmetric Loop under Inclined Conditions." Science and Technology of Nuclear Installations 2014 (2014): 1–8. http://dx.doi.org/10.1155/2014/925760.

Full text
Abstract:
Natural circulation is an important process for primary loops of some marine integrated reactors. The reactor works under inclined conditions when severe accidents happen to the ship. In this paper, to investigate the characteristics of natural circulation, experiments were conducted in a symmetric loop under the inclined angle of 0~45°. A CFD model was also set up to predict the behaviors of the loop beyond the experimental scope. Total circulation flow rate decreases with the increase of inclined angle. Meanwhile one circulation is depressed while the other is enhanced, and accordingly the disparity between the branch circulations arises and increases with the increase of inclined angle. Circulation only takes place in one branch circuit at large inclined angle. Also based on the CFD model, the influences of flow resistance distribution and loop configuration on natural circulation are predicted. The numerical results show that to design the loop with the configuration of big altitude difference and small width, it is favorable to reduce the influence of inclination; however too small loop width will cause severe reduction of circulation ability at large angle inclination.
APA, Harvard, Vancouver, ISO, and other styles
2

Britsch, Karl, Mark Anderson, Paul Brooks, and Kumar Sridharan. "Natural circulation FLiBe loop overview." International Journal of Heat and Mass Transfer 134 (May 2019): 970–83. http://dx.doi.org/10.1016/j.ijheatmasstransfer.2018.12.180.

Full text
APA, Harvard, Vancouver, ISO, and other styles
3

Baek, Seungwhan, Youngsuk Jung, and Kiejoo Cho. "Cryogenic two-phase natural circulation loop." Cryogenics 111 (October 2020): 103188. http://dx.doi.org/10.1016/j.cryogenics.2020.103188.

Full text
APA, Harvard, Vancouver, ISO, and other styles
4

Hariyanto, Duwi, and Sidik Permana. "Experimental Investigation of Natural Circulation in a Single-Phase Loop with Different Widths." International Journal of Electronics and Electrical Engineering 8, no. 2 (June 2020): 24–30. http://dx.doi.org/10.18178/ijeee.8.2.24-30.

Full text
Abstract:
The natural circulation loop is one of the design concepts of a cooling system in new advanced reactors that has attracted many researchers to develop it. This study aimed to perceive the effect of horizontal width variation on the thermal behavior of a single-phase Natural Circulation Loop (NCL). NCL apparatus with a vertical heater and a vertical cooler was designed for experimental study. The height of the loop was 100 cm while the width of the loop was varied at 50 cm and 100 cm. The heater was designed using Nichrome wire on the outside of the stainless pipe while the cooler was designed using pipe-in-pipe with water flowing through the annulus. Arduino microcontroller and K-type thermocouple sensors were used in temperature data acquisition. XAMPP software was used in data recording. The results of this study indicated that the loop of a 100 cm width has a difference in the temperature of the fluid coming out of the heater and entering the heater that reaches 156,0% higher than the loop of a 50 cm width at the same input voltage. This study is supposed to be one of the references for a single-phase natural circulation loop.
APA, Harvard, Vancouver, ISO, and other styles
5

Vijayan, P. K., A. K. Nayak, D. Saha, and M. R. Gartia. "Effect of Loop Diameter on the Steady State and Stability Behaviour of Single-Phase and Two-Phase Natural Circulation Loops." Science and Technology of Nuclear Installations 2008 (2008): 1–17. http://dx.doi.org/10.1155/2008/672704.

Full text
Abstract:
In natural circulation loops, the driving force is usually low as it depends on the riser height which is generally of the order of a few meters. The heat transport capability of natural circulation loops (NCLs) is directly proportional to the flow rate it can generate. With low driving force, the straightforward way to enhance the flow is to reduce the frictional losses. A simple way to do this is to increase the loop diameter which can be easily adopted in pressure tube designs such as the AHWR and the natural circulation boilers employed in fossil-fuelled power plants. Further, the loop diameter also plays an important role on the stability behavior. An extensive experimental and theoretical investigation of the effect of loop diameter on the steady state and stability behavior of single- and two-phase natural circulation loops have been carried out and the results of this study are presented in this paper.
APA, Harvard, Vancouver, ISO, and other styles
6

Kazachkovskii, O. D. "Thermal paradox of the natural circulation loop." Atomic Energy 85, no. 4 (October 1998): 710–13. http://dx.doi.org/10.1007/bf02368693.

Full text
APA, Harvard, Vancouver, ISO, and other styles
7

Huang, Zhencheng, Mingming Zhang, Shizhe Wen, and Zhenhui He. "Scaling of natural circulation loop operation modes." International Journal of Heat and Mass Transfer 90 (November 2015): 131–39. http://dx.doi.org/10.1016/j.ijheatmasstransfer.2015.06.018.

Full text
APA, Harvard, Vancouver, ISO, and other styles
8

Cammarata, L., A. Fichera, and I. D. Guglielmino. "Dynamic control for a natural circulation loop." Heat and Mass Transfer 39, no. 7 (July 1, 2003): 605–11. http://dx.doi.org/10.1007/s00231-002-0326-7.

Full text
APA, Harvard, Vancouver, ISO, and other styles
9

Kabankov, O. N., V. V. Yagov, and N. O. Zubov. "Experimental and computational study of a low-pressure natural circulation loop." Journal of Physics: Conference Series 2088, no. 1 (November 1, 2021): 012020. http://dx.doi.org/10.1088/1742-6596/2088/1/012020.

Full text
Abstract:
Abstract The experimental and analytical study of single-phase flow and heat transfer in natural circulation loop has been carried out. Experiments were performed on water and ethanol that are the liquids with significantly different thermophysical properties. Experimental apparatus was a rectangular shaped loop with vertical flow up leg. The flow up and flow down legs of the loop are joined to the separator-condenser at the top of the loop. The upper limit of heat flux densities in the experiments was set with the consideration for flow regime to remain in single phase state along the whole heated length. Wall temperature time records being registered at different distances from the inlet to the heated zone indicate the occurrence of temperature fluctuations near the exit from heated zone even at relatively low heat flux densities. This fact displaces a complex changing of velocity profiles along the tube with vortex formation and occurrence of flow instability. Experimental data on longitudinal wall temperature distributions of heated section have been used to test a modified method of hydraulic calculation of the loop. It was pointed out that in spite of long year (since early 1950s) experimental, analytical and numerical investigations of natural circulation loops no suitable predicting recommendations for heat transfer and friction have been proposed till today for engineering hydraulic calculations of single-phase natural circulation loops.
APA, Harvard, Vancouver, ISO, and other styles
10

Bejjam, Ramesh, and Kiran Kumar. "Numerical study on heat transfer characteristics of nanofluid based natural circulation loop." Thermal Science 22, no. 2 (2018): 885–97. http://dx.doi.org/10.2298/tsci160826087b.

Full text
Abstract:
In this paper the steady-state analysis has been carried out on single phase natural circulation loop with water and water based Al2O3 (Al2O3-water) nanofluid at 1%, 3%, 5%, and 6% particle volume concentrations. For this study, a 3-D geometry of natural circulation loop is developed and simulated by using the software, ANSYS (FLUENT) 14.5. Based on the Stokes number, mixture model is adopted to simulate the nanofluid based natural circulation loop. For the simulations, the imposed thermal boundary conditions are: constant heat input over the range of 200-1000 W with step size of 200 W at the heat source and isothermal wall temperature of 293 K at the heat sink. Adiabatic boundary condition is imposed to the riser and down-comer. The heat transfer characteristics and fluid-flow behavior of the loop fluid in natural circulation loop for different heat inputs and particle concentrations are presented. The result shows that the mass-flow rate of loop fluid in natural circulation loop is enhanced by 26% and effectiveness of the natural circulation loop is improved by 15% with Al2O3-water nanofluid when compared with water. All the simulation results are validated with the open literature in terms of Reynolds number and modified Grashof number. These comparisons confidently say that the present 3-D numerical model could be useful to estimate the performance of natural circulation loop.
APA, Harvard, Vancouver, ISO, and other styles
More sources

Dissertations / Theses on the topic "Natural circulation loop"

1

Latif, Medhat Gamil. "Modelling the simplified boiling water reactor natural circulation loop and its stability." Diss., The University of Arizona, 1993. http://hdl.handle.net/10150/186405.

Full text
Abstract:
An integrated model that estimates loop flow rate, heat removal, and stability parameters for the General Electric Simplified Boiling Water Reactor SBWR was developed. The three parameters above used to be calculated individually each by a separate code. The initial approach in loop thermal hydraulic modelling was the steady state solution of the SBWR loop mass, energy, and momentum equations. The power-to-flow map obtained proved to be quite comparable with the Natural Circulation in Boiling Water Reactor (NATBWR) code developed by EPRI, in addition to that of General Electric. At low power levels buoyancy forces are the controlling factor in determining the loop flow rate, while at high power levels two-phase friction losses become the dominating one. Evaluation criteria necessary for comparing different loop geometries performance have been the "minimum critical heat flux ratio (MCHFR)" and the "decay ratio." The predicted flow, from the DFM, at different power levels was used later in a parametric study to answer an important question of which combination of core and riser heights are to be selected that meets both the stability and critical power ratio limits. By modelling bubble time delay through riser in the loop momentum equation, a loop damping coefficient as a measure of loop stability, with higher damping meaning a more stable loop was calculated. Results indicated that during normal operation the SBWR loop is pretty damped. Finally, a detailed code that consists mainly of a fuel pin model, reactor point kinetics for the time dependent reactor normalized power with one group of delayed neutrons, and coolant channel mass, energy, and momentum equations is considered. Reactivity feedbacks from voids and fuel temperature, (Doppler effect), were considered. The loop momentum equation was modified to account for bubble time delay in the riser. After a small perturbation in reactivity, fuel temperature, core average void, and loop flow rate were shown to reach equilibrium values after a period of time equivalent to the transit time of the bubble through the riser. Results from this code matched that of the SBWR safety analysis report.
APA, Harvard, Vancouver, ISO, and other styles
2

Jacobs, Louis Egbert. "A conceptual study of a natural circulation cooling loop for a PWR containment / Jacobs L.E." Thesis, North-West University, 2011. http://hdl.handle.net/10394/7608.

Full text
Abstract:
The removal of heat from the containment building is an important consideration in the design of a nuclear power plant. In this investigation a simple rectangular natural circulation loop was simulated to determine whether it could possibly be used to remove usable quantities of heat from a containment building. The loop had a vertical pipe on the inside and outside of the containment building. These pipes acted as heat exchangers. Single phase and two phase cases were simulated by imposing a temperature on the respective vertical leg pipe walls and determining the heat absorption from the containment building. The heat was conveyed from the inside of the building to the outside via the natural circulation phenomenon. A literature study was done to cover topics relevant to this investigation. A theoretical model using conservation equations and control volumes was derived. This model was based largely on knowledge gleaned from the literature study. The theoretical model was a simple homogenous model, which was sufficiently detailed for a conceptual investigation. The theoretical model was then manipulated into a form suitable for use in a computer simulation program. Simplifications were made to the simulation model and underlying theory due to the nature of the investigation. The simulation model was validated against published experimental results. During the simulation phase a number of cases were investigated. These cases were divided into base cases and parametric studies. During the base case simulations the change of key fluid variables along the loop was examined. During the parametric studies the hot and cold leg inside wall temperatures, loop geometry and pipe diameter were varied. The effect of these parameters on the heat absorption from the containment was determined. The simulations showed that with the current assumptions about 75 to 120 of the natural circulation loops are needed depending on their geometry and containment conditions. The heat removal rates that were calculated varied from 50 kW to 600 kW for a single loop. As explained in the final chapter, there are many factors that influence the results obtained. The natural circulation concept was deemed to be able to remove usable quantities of heat from the containment building.
Thesis (M.Ing. (Nuclear Engineering))--North-West University, Potchefstroom Campus, 2012.
APA, Harvard, Vancouver, ISO, and other styles
3

Gros, Emilien B. "Liquid-Salt-Cooled Reactor start-up with natural circulation under Loss-of-Offsite-Power (LOOP) conditions." Thesis, Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/43745.

Full text
Abstract:
The Liquid-Salt-Cooled Very High-Temperature Reactor (LS-VHTR) was modeled using the neutronics analysis code SCALE6.0 and the thermal-hydraulics and kinetics modeling code RELAP5-3D with objective to devise, analyze, and evaluate the feasibility and stability of a start-up procedure for this reactor using natural circulation of the coolant and under the Loss Of Offsite Power (LOOP) conditions. This Generation IV reactor design has been studied by research facilities worldwide for almost a decade. While neutronics and thermal-hydraulics analyses have been previously performed to show the performance of the reactor during normal operation and for shutdown scenarios, no study has heretofore been published to examine the active or passive start-up of the reactor. The fuel temperature (Doppler) and coolant density coefficient of reactivity of the LS-VHTR were examined using the CSAS6 module of the SCALE6.0 code. Negative Doppler and coolant density feedback coefficients were calculated. Two initial RELAP5 simulations were run to obtain the steady-state conditions of the model and to predict the changes of the thermal-hydraulic parameters during the shutdown of the reactor. Next, a series of step reactivity additions to the core were simulated to determine how much reactivity can be inserted without jeopardizing safety and the stability of the core. Finally, a start-up procedure was developed, and the restart of the reactor with natural convection of the coolant was simulated. The results of the simulations demonstrated the potential of a passive start-up of the LS-VHTR.
APA, Harvard, Vancouver, ISO, and other styles
4

BOCANEGRA, CIFUENTES JOHAN AUGUSTO. "Lattice Boltzmann Method: applications to thermal fluid dynamics and energy systems." Doctoral thesis, Università degli studi di Genova, 2021. http://hdl.handle.net/11567/1060259.

Full text
Abstract:
In many energy systems fluids play a fundamental role, and computational simulations are a valuable tool to study their complex dynamics. The Lattice Boltzmann Method (LBM) is a relatively new numerical method for computational fluid dynamics, but its applications can be extended to physical phenomena beyond fluid flows. This thesis presents applications of the LBM to thermal fluid dynamics and energy systems. Specific applications considered are: application to nuclear reactor engineering problems; thermal fluid dynamic behavior of a Natural Circulation Loop; nanoparticles gravitational sedimentation; acoustical problems. The main original contributions derived from this work are: first, the systematic description of the current status of LBM applications to nuclear reactors problems, including test cases and benchmark simulations; second, the development and validation of a LBM model for a single-phase natural circulation loop; third, the development and validation of a LBM model for gravitational sedimentation of nanoparticles, and fourth, the systematic description of the current status of LBM applications to acoustics, including simulations of test cases. The development of this thesis was not limited to simulations; experimental studies in parallel connected natural circulation loops of small inner diameter were conducted, showing the wide applicability of the one-dimensional theoretical models used to validate the LBM results. Additional contributions derived from this work: 1. the applicability of the method to study neutron transport and nuclear waste disposal using porous materials was shown. 2. changes in the thermophysical performance of the natural circulation loop when the loop reached a non-laminar (transition) regime were found at a Reynolds number lower than the typical range. 3. variable diffusion and sedimentation parameters were effective to model the experimental sedimentation curves. In conclusion, this work shows that the LBM is a versatile and powerful computational tool that can be used beyond the common Computational Fluid Dynamics applications.
In many energy systems fluids play a fundamental role, and computational simulations are a valuable tool to study their complex dynamics. The Lattice Boltzmann Method (LBM) is a relatively new numerical method for computational fluid dynamics, but its applications can be extended to physical phenomena beyond fluid flows. This thesis presents applications of the LBM to thermal fluid dynamics and energy systems. Specific applications considered are: application to nuclear reactor engineering problems; thermal fluid dynamic behavior of a Natural Circulation Loop; nanoparticles gravitational sedimentation; acoustical problems. The main original contributions derived from this work are: first, the systematic description of the current status of LBM applications to nuclear reactors problems, including test cases and benchmark simulations; second, the development and validation of a LBM model for a single-phase natural circulation loop; third, the development and validation of a LBM model for gravitational sedimentation of nanoparticles, and fourth, the systematic description of the current status of LBM applications to acoustics, including simulations of test cases. The development of this thesis was not limited to simulations; experimental studies in parallel connected natural circulation loops of small inner diameter were conducted, showing the wide applicability of the one-dimensional theoretical models used to validate the LBM results. Additional contributions derived from this work: 1. the applicability of the method to study neutron transport and nuclear waste disposal using porous materials was shown. 2. changes in the thermophysical performance of the natural circulation loop when the loop reached a non-laminar (transition) regime were found at a Reynolds number lower than the typical range. 3. variable diffusion and sedimentation parameters were effective to model the experimental sedimentation curves. In conclusion, this work shows that the LBM is a versatile and powerful computational tool that can be used beyond the common Computational Fluid Dynamics applications.
APA, Harvard, Vancouver, ISO, and other styles
5

Ruppersberg, Johannes Coenraad. "Transient modelling of a loop thermosyphon : transient effects in single and two phase natural circulation thermosyphon loops suitable for the reactor cavity cooling of a pebble bed modular reactor." Thesis, Stellenbosch : Stellenbosch University, 2008. http://hdl.handle.net/10019.1/20858.

Full text
Abstract:
Thesis (MScIng)--University of Stellenbosch, 2008.
ENGLISH ABSTRACT: The focus of this project was the application of a passive device in the form of a loop thermosyphon as a reactor cavity cooling system (RCCS) for a Pebble Bed Modular Reactor. An extensive literature review showed that loop thermosyphons have been widely researched, both theoretically and experimentally. In the review attention has specifically been given to matters such as safety, instability, control and mathematical modelling. One of the objectives of the project was to build one of the axially symmetric sections of Dobson’s (2006) proposed full scale RCCS using a scaled down version consisting of a single loop heated by a section of the reactor pressure vessel and cooled by a tank of water. The second objective was to derive a theoretical model that could be used in a computer code to simulate the experiment. The theory and experiment would then be compared in order to verify the code. The mathematical model created used the following three major assumptions: quasistatic flow, incompressible liquid and vapour and one dimensionality. The conservation equations in the form of a set of difference equations with the appropriate closure equations were then solved explicitly. It was found that the theoretical results were heavily influenced by the surface optical properties as well as the heat transfer coefficients. The emissivity influenced the transition point from single to two-phase flow as well as the condenser outlet temperature. The single phase heat transfer coefficients influenced the condenser outlet temperature significantly while it was found that for two phase flow the combination of the available boiling and condensation heat transfer coefficients had only minor effects on the end results. A stainless steel and aluminium thermosyphon loop was built using water as the working fluid. A stainless steel heater plate provided the heat input while a 200 L water tank was the heat sink. Temperature and flow rate measurements were recorded as a function of time with various heating/cooling transients from start-up to steady state for three operating modes. The three operating modes were single phase, two-phase and heat pipe mode. It was found that the theoretical temperatures correspond reasonably well with the experimental temperatures. The time predicted by the theoretical model to reach the operating temperature was however somewhat longer than for the experimental. This is to be expected when considering that there is some uncertainty pertaining to the heat transfer coefficients as well as surface emissive properties. The correspondence of the theoretical and experimental fin temperatures was poor due to significant thermal stratification of the air separating the heater plate and fins. Several shortcomings in the theoretical model as well as the experimental setup were identified and discussed. The conclusion was reached that this exploratory study showed that the loop thermosyphon is a viable option for the RCCS and that the mathematical model is a viable theoretical simulation tool. Several recommendations were made for further study to address and overcome the shortcomings identified in the theoretical and experimental models in order to prove this conclusion. Amongst these is the determination of better material surface properties and heat transfer coefficients and improved mass flow rate measurement. Investigating scaling issues, natural convection outside the loop and updating of the computer program is also recommended.
AFRIKAANSE OPSOMMING: Die fokus van hierdie projek was die toepassing van passiewe apparatuur, in die vorm van ‘n geslote lus termoheuwel, as ‘n reaktor kamer verkoellings stelsel vir die korrel bed modulêre reaktor. Die literatuur studie wys dat hierdie tegnologie reeds breedvoerig ondersoek is teoreties sowel as eksperimenteel. In die literatuur oorsig word aandag spesifiek gegee aan veiligheid, onstabiliteit, beheer en modelleering. Een van die doelwitte van die projek was om ‘n klein skaalse model te bou van een van die aksiaal simmetriese seksies van Dobson (2006) se voorgestelde volskaalse reaktor kamer verkoellings stelsel. Die model bestaan uit n enkele lus verhit deur ‘n seksie van die reaktor drukvat en verkoel deur ‘n tenk vol water. Die tweede doelwit was die afleiding van ‘n teoretiese model wat in ‘n rekenaar program gebruik kan word om die eksperiment te simuleer. Die teoretiese en eksperimentele data kan dan vergelyk word om die geldigheid van die program te toets. Die volgende aanames is gemaak tydens die afleiding van die wiskundige model: kwasi-statiese vloei, onsamedrukbare vloeistof en gas en een dimensionalitiet. Die behouds wette is in die vorm van ‘n stel differensie vergelykings met die toepasbare sluitings vergelykings eksplisiet opgelos. Dit is bevind dat die teoretiese resultate swaar beinvloed is deur die materiaal oppervlak eienskappe sowel as die warmteoordrag koëffisiënte. Die emisiviteit beinvloed die oorgangs punt van enkel na twee fase vloei sowel as die kondenser uitlaat temperatuur. Die enkel fase warmteoordrag koëffisiënt het n beduidende invloed op die kondenser uitlaat temperatuur terwyl dit voorkom asof die spesifieke kombinasie van die koking en kondensasie warmteoordrag koëffisiënte minimale invloed op die resultate het in die twee fase gebied. Vlekvrye staal en aluminium is gebruik om die lus te bou met water as die verkoelings middel. Warmte is toegevoeg tot die stelsel deur ’n vlekvrye staal verhittings plaat terwyl ‘n 200 L water tenk die warmte onttrek het. Temperatuur en massa vloei tempo is aangeteken as ‘n funksie van tyd vir verskeie verhitting/verkoellings oorgangs gedragte vanaf begin tot bestendige toestand vir drie bedryfs modusse. Die drie bedryfs modusse was enkel fase, twee fase en hitte pyp modus. Dit is bevind dat die teoretiese temperature redelik goed ooreengekom het met die eksperimentele waardes. Die tyd wat dit neem om by die bedryfs temperatuur te kom soos voorspel deur die teorie is egter langer as wat in die eksperiment gevind is. Dit is te verstane wanneer die onsekerheid in die warmteoordrag koëffisiënte en materiaal oppervlak eienskappe in ag geneem word. Die fin temperature het ‘n swakker ooreenkoms getoon as gevolg van beduidende termiese stratifikasie van die lug tussen die fin en verhittings plaat. Verskeie tekortkominge in die teoretiese model en eksperimentele opstelling is geïdentifiseer en bespreek. Die gevolgtrekking is gemaak dat die ondersoek bewys dat geslote lus termoheuwels ‘n lewensvatbare opsie is vir ‘n reaktor kamer verkoellings stelsel en dat die wiskundige model lewensvatbaar is vir teoretiese simulasie. Verskeie aanbevelings word egter gemaak om die tekortkominge in die teoretiese en eksperimentele modelle aan te spreek om so doende die gevolgtrekking te staaf. Dit word aanbeveel dat beter waardes vir die materiaal oppervlak eienskappe en warmteoordrag koëffisiënte gevind word en verbeterde massa vloei meetings gedoen word. Dit word verder aanbeveel om skaleering asook natuurlike konveksie buite die lus te ondersoek en om die rekenaar program by te werk.
APA, Harvard, Vancouver, ISO, and other styles
6

Sittmann, Ilse. "Inside-pipe heat transfer coefficient characterisation of a one third height scale model of a natural circulation loop suitable for a reactor cavity cooling system of the Pebble Bed Modular Reactor." Thesis, Stellenbosch : University of Stellenbosch, 2011. http://hdl.handle.net/10019.1/6708.

Full text
Abstract:
Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2011.
ENGLISH ABSTRACT: The feasibility of a closed loop thermosyphon for the Reactor Cavity Cooling System of the Pebble Bed Modular Reactor has been the subject of many research projects. Difficulties identified by previous studies include the hypothetical inaccuracies of heat transfer coefficient correlations available in literature. The aim of the research presented here is to develop inside-pipe heat transfer correlations that are specific to the current design of the RCCS. In order to achieve this, a literature review is performed which identifies reactors which employ closed loop thermosyphons and natural circulation. The literature review also explains the general one-dimensional two-fluid conservation equations that form the basis for numerical modelling of natural circulation loops. The literature review lastly discusses available heat transfer coefficient correlations with the aim of identifying over which ranges and under which circumstances these correlations are considered accurate. The review includes correlations commonly used in natural circulation modelling in the nuclear industry in aims of identifying correlations applicable to the modelling of the proposed RCCS. One of the objectives of this project is to design and build a one-third-height-scale model of the RCCS. Shortcomings of previous experimental models were assessed and, as far as possible, compensated for in the design of the model. Copper piping is used, eliminating material and surface property uncertainties. Several sight glasses are incorporated in the model, allowing for the visual identification of two-phase flow regimes. An orifice plate is used allowing for bidirectional flow measurement. The orifice plate, thermocouples and pipe-in-pipe heat exchangers are calibrated in-situ to minimize experimental error and aid repeatability. Twelve experiments are performed with data logging occurring every ten seconds. The results presented here are limited to selected single and two-phase flow operating mode results. Error analyses and repeatability of experimental measurements for single and two-phase operating modes as well as cooling water mass flow rates are performed, to show repeatability of experimental results. These results are used to mathematically determine the experimental inside-pipe heat transfer coefficients for both the evaporator and condenser sections. Trends in the heat transfer coefficient profiles are identified and the general behaviour of the profiles is thoroughly explained. The RCCS is modelled as a one-dimensional system. Correlations for the friction factor, heat transfer coefficient, void fraction and two-phase frictional multiplier are identified. The theoretical heat transfer coefficients are calculated using the mathematical model and correlations identified in the literature review. Fluid parameters are evaluated using experimentally determined temperatures and mass flow rates. The resulting heat transfer coefficient profiles are compared to experimentally determined profiles, to confirm the hypothesis that existing correlations do not accurately predict the inside-pipe heat transfer coefficients. The experimentally determined coefficients are correlated to 99% confidence intervals. These generated correlations, along with identified and established twophase heat transfer coefficient correlations, are used in a mathematical model to generate theoretical coefficient profiles. These are compared to the experimentally determined coefficients to show prediction accuracy.
AFRIKAANSE OPSOMMING: Die haalbaarheid van ‘n natuurlike sirkulasie geslote lus vir die Reaktor Holte Verkoeling Stelsel (RHVS) van die Korrelbed Modulêre Kern-Reaktor (KMKR) is die onderwerp van talle navorsings projekte. Probleme geïdentifiseer in vorige studies sluit in die hipotetiese onakkuraatheid van hitte-oordrag koëffisiënt korrelasies beskikbaar in literatuur. Die doel van die navorsing aangebied is om binne-pyp hitte-oordrag koëffisiënt korrelasies te ontwikkel spesifiek vir die huidige ontwerp van die RHVS. Ten einde dit te bereik, word ‘n literatuurstudie uitgevoer wat kern-reaktors identifiseer wat gebruik maak van natuurlike sirkulasie lusse. Die literatuurstudie verduidelik ook die algemene een-dimensionele twee-vloeistof behoud vergelykings wat die basis vorm vir numeriese modellering van natuurlike sirkulasie lusse. Die literatuurstudie bespreek laastens beskikbare hitte-oordrag koëffisiënt korrelasies met die doel om te identifiseer vir welke massavloei tempo waardes en onder watter omstandighede hierdie korrelasies as korrek beskou is. Die ontleding sluit korrelasies in wat algemeen gebruik word in die modellering van natuurlike sirkulasie in die kern industrie met die hoop om korrelasies vir gebruik in die modellering van die voorgestelde RHVS te identifiseer. Een van die doelwitte van die projek is om ‘n een-derde-hoogte-skaal model van die RHVS te ontwerp en te bou. Tekortkominge van vorige eksperimentele modelle is geidentifiseer en, so ver as moonlik, voor vergoed in die ontwerp van die model. Koper pype word gebruik wat die onsekerhede van materiaal en opperkvlak eindomme voorkom. Verkseie deursigtige polikarbonaat segmente is ingesluit wat visuele identifikasie van twee-fase vloei regimes toelaat. ‘n Opening plaat word gebruik om voorwaartse en terugwaartse vloeimeting toe te laat. Die opening plaat, termokoppels en hitte uitruilers is gekalibreer in plek om eksperimentele foute te verminder en om herhaalbaarheid te verseker. Twaalf eksperimente word uitgevoer en data word elke tien sekondes aangeteken. Die resultate wat hier aangebied word, is beperk tot geselekteerde enkel- en tweefase vloei meganismes van werking. Fout ontleding en herhaalbaarheid van eksperimentele metings, om die herhaalbaarheid van eksperimentele resultate te toon. Hierdie is gebruik om wiskundig te bepaal wat die eksperimentele binne-pyp hitte-oordrag koëffisiënte is vir beide die verdamper en kondenseerder afdelings. Tendense in die hitte-oordrag koëffisiënt profiele word geïdentifiseer en die algemene gedrag van die profiles is deeglik verduidelik. Die RHVS is gemodelleer as 'n een-dimensionele stelsel. Korrelasies vir die wrywing faktor, hitte-oordrag koëffisiënte, leegte-breuk en twee-fase wrywings vermenigvuldiger word geïdentifiseer. Die teoretiese hitte-oordrag koëffisiënte word bereken deur middle van die wiskundige model en korrelasies wat in literatuur geidentifiseer is. Vloeistof parameters is geëvalueer met eksperimenteel bepaalde temperature en massa-vloei tempos. Die gevolglike hitte-oordrag koëffisiënt profiles is vergelyk met eksperimentele profiele om die hipotese dat die bestaande korrelasies nie die binne-pyp hitte-oordrag koëffisiënte akkuraat voorspel nie, te bevestig. Die eksperimenteel bepaalde koëffisiënte is gekorreleer en die gegenereerde korrelasies, saam met geïdentifiseerde twee-fase hitte-oordrag koëffisiënt korrelasies, word gebruik in 'n wiskundige model om teoretiese koëffisiënt profiele te genereer. Dit word dan vergelyk met die eksperimenteel bepaalde hitteoordrag koëffisiënte om die akkuraatheid van voorspelling te toon. Tekortkominge in die teoretiese en eksperimentele model word geïdentifiseer en aanbevelings gemaak om hulle aan te spreek in die toekoms.
APA, Harvard, Vancouver, ISO, and other styles
7

Angelo, Gabriel. "Análise numérica da dinâmica do escoamento em circuitos de circulação natural." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/85/85133/tde-20092013-092635/.

Full text
Abstract:
Circuitos de convecção natural ou sistemas de circulação natural são empregados em diversas áreas da engenharia. Reatores nucleares refrigerados a água utilizam circuitos de circulação natural como método passivo de seguranca. Em situações críticas, sem qualquer controle externo, o sistema permanece em segurança por suas próprias características de funcionamento (intrinsecamente seguro). O trabalho proposto consiste em estudar numericamente o circuito de circulação natural de água, localizado no Instituto de Pesquisas Energéticas e Nucleares / Comissão Nacional de Energia Nuclear em São Paulo, por meio do uso de modelos matemáticos, objetivando determinar o padrão do escoamento em condições sem mudança de fase líquido-vapor. A comparação dos resultados de temperatura obtidos por cada um dos modelos de turbulência aos pontos instrumentados no circuito experimental, na condição transitória, revelou desvios significativos nas respostas do modelo de zero equação. Desvios intermediário foram observados nos modelos de transporte da viscosidade turbulenta (EVTE), k - ω, SST e SSG e resultados melhores foram vericados nos modelos k - ε e DES (com significativa superioridade do primeiro modelo).
Natural circulation loops apply to many engineering applications such as: water heating solar energy system (thermo-siphons), thermal management of electrical components (voltage converter), geothermal energy, nuclear reactors, etc. In pressurized water nuclear reactors, known as PWR\'s, the natural circulation loops are employed to ensure passive safety. In critical situations, the heat transfer will occur only by natural convection, without any external control or mechanical devices. This feature is desired and has been considered in modern nuclear reactor projects. This work consists of a numerical study of the natural circulation loop, located at the Instituto de Pesquisas Energeticas e Nucleares / Comissão Nacional de Energia Nuclear in São Paulo, Brazil, in order to establish the ow pattern in single phase conditions. The comparison of numerical results to experiments in transient condition revealed significant deviations for the Zero Equation turbulence model. Intermediate deviations for the Eddy Viscosity Turbulence Equation (EVTE), k - ω, SST e SSG models. And the best results are obtained by the k - ε e DES models (with better results for the k - ε model).
APA, Harvard, Vancouver, ISO, and other styles
8

ZHANG, YOING-RUI, and 張永瑞. "Steady state analysis of two-phase natural circulation loop." Thesis, 1987. http://ndltd.ncl.edu.tw/handle/34267129721991166635.

Full text
APA, Harvard, Vancouver, ISO, and other styles
9

Wang, Sing-Biau, and 王勝標. "Two-Phase Flow Instability Experiment in a Natural Circulation Loop." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/31811771321512584155.

Full text
Abstract:
博士
國立清華大學
工程與系統科學系
86
Two-Phase Flow Instability Experiment in a Natural Circulation Loop Abstract Because of their high heat transfer capability, simplicity, and inherently safe nature, two phase natural circulation loops have manyindustrial applications, such as waste heat recovery, chemical processes using thermosiphon reboilers, and the next generation boiling water reactor. The thermal-hydraulic instability of a two-phase natural circulation loop, which is a complex multivariable system with high non-linearity, was investigated experimentally based on the Taguchi method. Excellent results were obtained and a broad picture of the trends producedby the various parameters that affect instability is presented. This study concluded that, within the experimental range, the inlet temperature,heating power and the presence of the unheated bypass channel are the three most dominant factors affecting the loop instability. The Taguchi method is found to be very efficient and there is a great deal of savingin the experimental work. The 20 runs of experiment based on the Taguchi method suggests that the stability of the present two-phase natural circulation loop would be improved under the following conditions: decreased inlet temperature, decreased thermal load, disconnected unheated bypass channel, installing the compressible volume with a higher water level in the downstream two-phase flow region, disconnected upstream compressiblevolume, increased single-phase flow restrictions, and decreased two-phase flow restrictions. Although the same trends bear the standard method of stabilizing a boiling channel, the restriction factors in the presentexperimental investigation are found to be ineffective in dampening the thermal-hydraulic instability. ( Keywords: two-phase flow, natural circulation loop, instability, Taguchi method )
APA, Harvard, Vancouver, ISO, and other styles
10

Mahmoudi, Javad. "Experimental thermal-hydraulic study of a supercritical CO2 natural circulation loop." 2014. http://hdl.handle.net/1993/23350.

Full text
Abstract:
Experimental thermal-hydraulic study of a rectangular supercritical CO2 natural-circulation loop with a horizontal heated channel was conducted at different steady-state conditions. These included different system pressures and three different inlet temperatures, with different inlet and outlet valve openings. Approximately, 450 experimental steady-state data-points were collected. The data include measurements of pressure-drop along the heated channel, pressure-drop across inlet and outlet valves, applied heat on the heated channel, pressure, temperature and flow-rate. Steady-state curves of mass flow-rate versus power, outlet temperature versus power, and detailed information of frictional pressure drop and local head loss coefficients were produced. Comparison showed that for the available experimental set-up, computed frictional pressure-drops fell within 1-1.20 of the Blasius formula prediction. Moreover, flow oscillations were observed in several cases when outlet temperature of CO2 was higher than the pseudo-critical temperature on the negative slope part of the mass flow-rate versus power curve.
APA, Harvard, Vancouver, ISO, and other styles
More sources

Books on the topic "Natural circulation loop"

1

Pilkhwal, D. S. Experiments in an natural circulation loop with supercritical water at low powers. Mumbai: Scientific Information Resource Division, Bhabha Atomic Research Centre, 2013.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
2

K, Bagul R., and Bhabha Atomic Research Centre, eds. Steady state experiments in high pressure natural circulation loop (HPNCL): [BARC report]. Mumbai: Bhabha Atomic Research Centre, 2009.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
3

K, Bagul R., and Bhabha Atomic Research Centre, eds. Steady state experiments in high pressure natural circulation loop (HPNCL): [BARC report]. Mumbai: Bhabha Atomic Research Centre, 2009.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
4

K, Bagul R., and Bhabha Atomic Research Centre, eds. Steady state experiments in high pressure natural circulation loop (HPNCL): [BARC report]. Mumbai: Bhabha Atomic Research Centre, 2009.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
5

Vijayan, P. K. Steady state and stability characteristics of a supercritical pressure natural circulation loop (SPNCL) with CO₂. Mumbai: Scientific Information Resource Division, Bhabha Atomic Research Centre, 2013.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
6

W, Ambrosini, U.S. Nuclear Regulatory Commission. Office of Nuclear Regulatory Research, Autoridad Regulatoria Nuclear (Argentina), and Università di Pisa. Dipartimento di costruzioni meccaniche e nucleari, eds. Verification of RELAP5/MOD 3 with theoretical and numerical stability results on single-phase, natural circulation in a simple loop. Washington, DC: Office of Nuclear Regulatory Research, U.S. Nuclear Regulatory Commission, 1999.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
7

W, Ambrosini, U.S. Nuclear Regulatory Commission. Office of Nuclear Regulatory Research., Autoridad Regulatoria Nuclear (Argentina), and Università di Pisa. Dipartimento di costruzioni meccaniche e nucleari., eds. Verification of RELAP5/MOD 3 with theoretical and numerical stability results on single-phase, natural circulation in a simple loop. Washington, DC: Office of Nuclear Regulatory Research, U.S. Nuclear Regulatory Commission, 1999.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
8

K, Vijayan P., and Bhabha Atomic Research Centre, eds. Investigations on the effect of heater and cooler orientation on the steady state, transient and stability behaviour of single-phase natural circulation in a rectangular loop. Mumbai: Bhabha Atomic Research Centre, 2001.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
9

Gartia, M. R. A generalised flow correlation for two-phase natural circulation loops. Mumbai: Bhabha Atomic Research Centre, 2005.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
10

Centre, Bhabha Atomic Research, ed. Experimental investigations in two-phase natural circulation loops relevant to the AHWR. Mumbai: Bhabha Atomic Research Centre, 2005.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
More sources

Book chapters on the topic "Natural circulation loop"

1

Venkata Sai Sudheer, S., K. Kiran Kumar, and Karthik Balasubramanian. "Effect of Loop Diameter on Two-Phase Natural Circulation Loop Performance." In Numerical Heat Transfer and Fluid Flow, 425–32. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-13-1903-7_49.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Vaidya, A. M., N. K. Maheshwari, and P. K. Vijayan. "Steady State and Transient Characteristics of Natural Circulation Loop." In Fluid Mechanics and Fluid Power – Contemporary Research, 1629–39. New Delhi: Springer India, 2016. http://dx.doi.org/10.1007/978-81-322-2743-4_155.

Full text
APA, Harvard, Vancouver, ISO, and other styles
3

Saha, Ritabrata, Koushik Ghosh, Achintya Mukhopadhyay, and Swarnendu Sen. "Effect of Loop Geometry on the Flow Dynamics of a Single-Phase Natural Circulation Loop." In Lecture Notes in Mechanical Engineering, 397–408. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-7831-1_36.

Full text
APA, Harvard, Vancouver, ISO, and other styles
4

Rai, Santosh Kumar, Pardeep Kumar, and Vinay Panwar. "Computational Analysis of Static Flow Instabilities in Supercritical Natural Circulation Loop." In Lecture Notes in Mechanical Engineering, 387–95. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-7831-1_35.

Full text
APA, Harvard, Vancouver, ISO, and other styles
5

Paruya, S., and P. Bhattacharya. "Dynamic Voids Measurement during Geysering Phenomenon in a Natural Circulation Loop." In New Trends in Fluid Mechanics Research, 471–74. Berlin, Heidelberg: Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/978-3-540-75995-9_151.

Full text
APA, Harvard, Vancouver, ISO, and other styles
6

Ozawa, Mamoru, Yoshihisa Asao, and Nobuyuki Takenaka. "Density Wave Oscillation in a Natural Circulation Loop of Liquid Nitrogen." In Instabilities in Multiphase Flows, 113–24. Boston, MA: Springer US, 1993. http://dx.doi.org/10.1007/978-1-4899-1594-8_9.

Full text
APA, Harvard, Vancouver, ISO, and other styles
7

Chouhan, Rakesh, A. Borgohain, A. K. Shrivastava, N. K. Maheshwari, and P. K. Vijayan. "CFD Analysis of Molten Fluoride Salt Natural Circulation in a Rectangular Loop." In Thorium—Energy for the Future, 431–44. Singapore: Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-13-2658-5_36.

Full text
APA, Harvard, Vancouver, ISO, and other styles
8

Zhang, Lei, Vijay Chatoorgoon, and Robert Derksen. "Experimental Flow Instability Study of a Natural Circulation Loop with Supercritical CO2." In Proceedings of The 20th Pacific Basin Nuclear Conference, 121–41. Singapore: Springer Singapore, 2017. http://dx.doi.org/10.1007/978-981-10-2314-9_10.

Full text
APA, Harvard, Vancouver, ISO, and other styles
9

Thimmaiah, Srivatsa, Tabish Wahidi, Ajay Kumar Yadav, and M. Arun. "Numerical Instability Assessment of Natural Circulation Loop Subjected to Different Heating Conditions." In Lecture Notes in Mechanical Engineering, 249–62. Singapore: Springer Singapore, 2022. http://dx.doi.org/10.1007/978-981-16-6928-6_21.

Full text
APA, Harvard, Vancouver, ISO, and other styles
10

Wahidi, Tabish, and Ajay Kumar Yadav. "Comparative Numerical Appraisal of Subcritical and Supercritical CO2-Based Natural Circulation Loop." In Lecture Notes in Mechanical Engineering, 263–75. Singapore: Springer Singapore, 2022. http://dx.doi.org/10.1007/978-981-16-6928-6_22.

Full text
APA, Harvard, Vancouver, ISO, and other styles

Conference papers on the topic "Natural circulation loop"

1

Moussavian, Seyed Khalil, Mario Misale, Francesco D’Auria, and Mahmoud Salehi. "Stability Behavior of Single-Phase Natural Circulation Loop." In ASME 2003 International Mechanical Engineering Congress and Exposition. ASMEDC, 2003. http://dx.doi.org/10.1115/imece2003-43597.

Full text
Abstract:
The circulating fluid in natural circulation loops would absorb heat from the hot zone (source) and will transport it to the cold zone (sink) without using of any mechanical pumps or other devices. The fluid density differences in hot and cold zones would lead buoyancy force which is introduced as the body force for the loop. By introducing the one-dimensional conservation equations; mass, momentum and energy in the loop and applying the perturbation method, or linear stability theory, would help us to study the stability of the rectangular natural circulation loop. The conservation equations in transient form were solved using the finite difference method. The results obtained from the linear and nonlinear stability studies would be compared with the experimental data of DITEC loop (LOOP#1) obtained at the University of Genova and with other suitable data in the literature.
APA, Harvard, Vancouver, ISO, and other styles
2

Kim, M. J., H. M. Chang, J. G. Weisend, John Barclay, Susan Breon, Jonathan Demko, Michael DiPirro, et al. "NATURAL CIRCULATION LOOP OF SUBCOOLED LIQUID NITROGEN." In ADVANCES IN CRYOGENIC ENGINEERING: Transactions of the Cryogenic Engineering Conference - CEC, Vol. 52. AIP, 2008. http://dx.doi.org/10.1063/1.2908604.

Full text
APA, Harvard, Vancouver, ISO, and other styles
3

Wu, Qiao, and James J. Sienicki. "Stability Analysis on Single-Phase Natural Circulation in Argonne Lead Loop Facility." In 10th International Conference on Nuclear Engineering. ASMEDC, 2002. http://dx.doi.org/10.1115/icone10-22375.

Full text
Abstract:
One-dimensional linear stability analysis was performed for single-phase lead-bismuth eutectic natural circulation. The Nyquist criterion and a root search method were employed to find the linear stability boundary of both forward and backward circulations. It was found that the natural circulations could be linearly unstable in a high Reynolds number region. Increasing loop friction makes a forward circulation more stable, but destabilizes the corresponding backward circulation under the same heating/cooling conditions. The characteristic wavelength of an unstable disturbance is roughly equal to the entire loop length.
APA, Harvard, Vancouver, ISO, and other styles
4

Knaani, Alexander, and Yoram Zvirin. "INVESTIGATION OF A TWO PHASE NATURAL CIRCULATION LOOP." In International Heat Transfer Conference 9. Connecticut: Begellhouse, 1990. http://dx.doi.org/10.1615/ihtc9.4120.

Full text
APA, Harvard, Vancouver, ISO, and other styles
5

Srivastava, A. K., Nadella Saikrishna, A. Borgohain, N. K. Maheshwari, D. S. Pilkhwal, and Avaneesh Sharma. "STABILITY STUDIES OF MOLTEN SALT NATURAL CIRCULATION LOOP." In Proceedings of the 24th National and 2nd International ISHMT-ASTFE Heat and Mass Transfer Conference (IHMTC-2017). Connecticut: Begellhouse, 2018. http://dx.doi.org/10.1615/ihmtc-2017.750.

Full text
APA, Harvard, Vancouver, ISO, and other styles
6

Fichera, A., G. Muscato, A. Pagano, and M. G. Xibilia. "A neural controller for a natural circulation loop." In 2001 European Control Conference (ECC). IEEE, 2001. http://dx.doi.org/10.23919/ecc.2001.7075941.

Full text
APA, Harvard, Vancouver, ISO, and other styles
7

Világi, František, Branislav Knížat, Róbert Olšiak, František Ridzoň, and František Urban. "Steady state estimation of a natural circulation loop." In THE PROCEEDINGS OF THE 5TH INTERNATIONAL CONFERENCE ON MARITIME EDUCATION AND TRAINING (The 5th ICMET) 2021. AIP Publishing, 2023. http://dx.doi.org/10.1063/5.0120084.

Full text
APA, Harvard, Vancouver, ISO, and other styles
8

Shi, Leitai, Guanghui Su, Tan Bing, Ronghua Chen, Wenxi Tian, Suizheng Qiu, and Junmei Wu. "Experimental Study on Natural Circulation in a Lead Bismuth Eutectic Loop." In 2017 25th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/icone25-66261.

Full text
Abstract:
In order to investigate the thermal-hydraulic characteristics of LBE in Accelerator Driven System (ADS), the Natural Circulation Capability Loop (NCCL) test facility was designed and constructed at Xi’An Jiaotong university in 2015. NCCL is a middle-scale experimental loop designed for investigating the natural circulation capacity, gas-lift pump enhancing circulation capacity and heat-transfer characteristic of LBE. For the natural circulation capability experiment, the loop is filled with argon gas at 0.2 MPa before filling LBE from store tank. The maximum temperature of LBE is 500 C°, while the normal operation temperature was maintained at 400 C°. In this paper, the LBE natural circulation characteristics were investigated with experiments in NCCL test facility. The study includes measurements on start-up of natural circulation and capability of natural circulation. Significant natural convection flow was observed in the experiments. It was found that the natural circulation was quickly established and stabilized due to LBE high thermal expansion property. It took only a few minutes to have a stable natural circulation prevailing from cold conditions. At the same time, the temperature difference between heating section and cooling section increase quickly and reach to the maximum value. And in the range of 10 minutes, a steady circulation can be performed. The natural circulation flowrate depends on the loop resistance, and the temperature difference between the hot leg and the cold leg, as determined by the power level and the heat sink capacity. The experiments show that the maximum flowrate for the natural circulation is 0∼0.81 kg/s.
APA, Harvard, Vancouver, ISO, and other styles
9

Li, ZhongChun, JiYang Yu, and XiaoMing Song. "Stability Analysis of a Supercritical Water Natural Circulation Loop." In 2012 20th International Conference on Nuclear Engineering and the ASME 2012 Power Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/icone20-power2012-55081.

Full text
Abstract:
As a part of “supercritical water reactor basic research”, the stability of the natural circulation research plays an important role on the feasibility of supercritical water reactor and experiment research. In this paper, the stability of a supercritical water natural circulation loop built by Department of Engineering Physics, Tsinghua University was studied by numerical method. It was confirmed that the static or Ledinegg instability doesn’t occur in HACA system, and there are no instabilities existing when the inlet enthalpy is larger than critical enthalpy. Instability was observed by numerical way, which is similar to DWOs and PDOs in two phase natural circulation loop. The system parameters’ influence on the instability of supercritical natural circulation loop was studied.
APA, Harvard, Vancouver, ISO, and other styles
10

Zhu, Hongye, Xingtuan Yang, Haibo Lian, and Shengyao Jiang. "Experimental and Numerical Study on Natural Circulation Under Inclined Condition." In 2013 21st International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/icone21-15444.

Full text
Abstract:
Natural circulation systems are broadly used in marine environments. When accidents happen, these systems may work under inclined condition. In this paper, we conducted a series of experimental study on the thermohydraulics behavior of natural circulation in a symmetric two-circuit loop under the inclined angle from 0∼45°. A CFD model is also set up and predicts the results well in comparing with the experiments. Both experimental and numerical analysis show that with the increase of inclined angle, the total circulation flow rate decreases. When the loop inclines about the axis perpendicular to the circulation, one circulation is depressed while the other is enhanced; accordingly the disparity between the branch circulations arises and increases with the increase of inclined angle. The flow pattern of the circulation under larger inclined angle (45∼90°) condition is also studied by CFD model. At large inclined angle the circulation is mainly happens in one circuit. Also based on this model, the influences of flow resistance distribution and loop configuration on natural circulation are predicted. The numerical results show that to design the loop with the configuration of big altitude difference and small width are favorable to confine the influence of inclination; however too small loop width will cause sever reduction of circulation ability in large angle inclination.
APA, Harvard, Vancouver, ISO, and other styles

Reports on the topic "Natural circulation loop"

1

Umekawa, Hisashi, Mamoru Ozawa, and Naoki Ishida. Quenching phenomena in natural circulation loop. Office of Scientific and Technical Information (OSTI), September 1995. http://dx.doi.org/10.2172/107007.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Middleton, Bobby D., Salvador B. Rodriguez, and Matthew David Carlson. Design Construction and Operation of a Supercritical Carbon Dioxide (sCO2) Loop for Investigation of Dry Cooling and Natural Circulation Potential for Use in Advanced Small Modular Reactors Utilizing sCO2 Power Conversion Cycles. Office of Scientific and Technical Information (OSTI), November 2015. http://dx.doi.org/10.2172/1226786.

Full text
APA, Harvard, Vancouver, ISO, and other styles
You might also be interested in the extended bibliographies on the topic 'Natural circulation loop' for particular source types:
Journal articles Dissertations / Theses Books
We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!

To the bibliography