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Soom, Mohd Amin Mohd. "Hydraulic analysis of trickle lateral." Thesis, University of Southampton, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.277631.
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Inderelst, Martin, David Prust, and Michael Siegmund. "Electro-hydraulic SWOT-analysis on electro-hydraulic drives in construction machinery." Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71235.
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This paper discusses the potential of centralized or decentralized electro-hydraulic (EH)-drives in comparison to conventional hydraulic systems. The systems are presented in diagrams covering the major electric and hydraulic components for an exemplary application, but also include specific technical data like the sizing of the components according to power, pressure, rotational speeds etc. In a second step, all systems are compared and evaluated based on criteria like design effort, energy saving potential, controllability, and servicing and maintenance of the machine. The resulting effects on fuel consumption are summarized as well. Finally, an evaluation of the potential of EH-drives in construction machinery and a derivation of the demands for future customization of electro-hydraulic linear drives is given on the basis of a SWOT-analysis from the point of view of a construction machinery OEM.
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Tranová, Kateřina. "Hydraulická analýza vodovodní sítě městské části Brno - Ivanovice." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2017. http://www.nusl.cz/ntk/nusl-265396.
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This diploma´s thesis aims to model the hydraulic model of the Brno – Ivanovice water supply system. The software MIKE URBAN for model hydraulic model of water supply system was used. It was performed a simulation of the various states of loading. The water supply system was assessment of pressure ratios. The outcome of this work is calibrated hydraulic model of water supply system. The appendix consists also of drawings, which represented pressure ratios, which are situated on water supply system. On the fourth drawing is described transparent situation of Brno-Ivanovice water supply system.
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LI, Zhen. "Analysis of dropbox assisted hydraulic traction." Thesis, KTH, Maskinkonstruktion (Inst.), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-209486.
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The research looks at the advantages and disadvantages of a hydraulic auxiliary drive (HAD) system which is installed on a 25 meter long timber transport vehicle. The purpose is to investigate the performance with regard to energy, economy and environment of the system due to the added components, the hydraulic accumulators. The auxiliary system that is used on the vehicle is simply a hydrostatic transmission system. Ideally, the fuel consumption and cost can be reduced by using accumulators. To verify this hypothesis, model-based simulations were performed in a software environment and the result was analyzed for a linear and repeatedly accelerating and decelerating driving cycle. Additionally, comparisons were made between the HAD system with and without the assistance of accumulators. From the simulation results, the system assisted by accumulators consumes approximately 14% less fuel than the other. And it produces 15% more tractive effort when the vehicle is accelerating. The paper also includes the determination of the size of accumulators, both theoretically and with simulations. By comparison, there is a small difference between the results from the theoretical calculation and the simulations, which might be caused by a neglecting the volumetric losses in the simulation process. Ideally, an accumulator with a size of 57 L was found to be the most efficient size for the studied driving cycle. Beyond that speed, the efficiency will decrease to some extent. Physical tests are not presented in this paper, but they will be done in the future.Den presenterade forskningen studerade fördelar och nackdelar med ett hydraulisk hjälpsystem för fordonsdrift (HAD) för en 25 meter lång timmerlastbil. Syftet var att undersöka hur drivlinans prestanda med avseende på energy, ekonomi och miljöpåverkan, påverkas av de adderade komponenterna, de hydrauliska ackumulatorerna. Hjälpsystemet är helt enkelt ett hydrostatiskt transmissionssystem. Idealt, kan bränsleförbrukning och kostnad reduceras genom att använda ackumulatorer i systemet. För att verifiera denna hypotes, har modell-baserade simuleringar utförts och resultaten har analyserats för konstantfartskörning och en körcykel med upprepade accelerationer och inbromsningar. Dessutom, har ett HAD-system med och utan ackumulator jämförts. Simuleringsresultaten visar att ett system med ackumulatorer förbrukar ca 14% mindre bränsle än ett system utan ackumulatorer. Ett ackumulatorstött system ger också 15% högre framdrivningseffekt vid accelereration. I avhandlingen dimensionera också storleken på ackumulatorerna, både teoretiskt och med simuleringar. Det finns en liten skillnad mellan resultaten från den teoretiska beräkningen och simuleringarna, som kan bero på att volymetriska förlusterna inte har tagits med i simuleringarna. En ackumulator med en storlek på 57 L visar sig ha den mest effektiva storleken för den studerade körcykeln. Vid högre körhastigheter, kommer verkningsgraden att minska till viss del. Inga fysiska tester har gjorts, men de kommer att utföras i framtiden.
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Tulasigeri, Sanjeev Suresh. "Failure Analysis of Hydraulic Jar Component." Thesis, University of Louisiana at Lafayette, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10245237.
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Reliability of equipment during well construction is necessary. Failure of components increases non-productive time and may cause injuries or loss of life. The jar is a component used in well construction, usually as part of the drill string to free stuck pipe or during fishing. It is subject to impact loads due to the hammering and tensile loads caused due to hook loads on the drill string. In this work, a root cause is failure analysis of failed component. The failure is different from all the other cases due to the reason that most of the time the component collapses and rather fails completely. The main objective is to find the root cause of failure. The visual inspection indicates signs of tensile and brittle failure. The scanning electron microscope analyses show evidence of fatigue: the classic beach mark striations. The presence of aluminum and voids in the section show that the material used for manufacture was of low quality. In this paper, efforts are made to provide recommendations to the company that rents these jars. The various causes of failure mentioned can be useful to have better understanding and control of the manufacturing process, improved instructions for the use of the jar, improve the overall reliability of the component, and use it for well construction with the safety of personnel and minimum non-productive time.
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KRUTZ, JILL E. "DESIGN OF A HYDRAULIC ACTUATOR TEST STAND FOR NON-LINEAR ANALYSIS OF HYDRAULIC ACTUATOR SYSTEM." University of Cincinnati / OhioLINK, 2001. http://rave.ohiolink.edu/etdc/view?acc_num=ucin990813095.
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Bruns, Joel. "Dynamic Analysis of a Hydraulic Body Mount." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu149407914091249.
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Kassfeldt, Elisabet. "Analysis and design of hydraulic cylinder seals." Doctoral thesis, Luleå tekniska universitet, Maskinelement, 1987. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-17192.
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Hydraulic cylinder seal performance is studied experimentally and theoretically. The seal performance is discussed in terms of friction force and oil leakage, which are due to the oil film build-up in the seal contact. The theoretical analysis is based both on calculated and measured contact pressure distributions. The compressibility of seal materials is determined experimentally, and it is shown that the compressibility is a pressure dependent material property. A method for calculation of the contact pressure distribution for a seal with an arbitrary cross-section is proposed, based on geometrical considerations and the experimentally determined compressibility. The pressure calculations are verified experimentally. Theoretically calculated oil film thicknesses in a seal contact are compared with measured film thicknesses. The increase of film thickness with increasing sliding velocity shows a good agreement between theory and experiment. The oil film is thicker in the experiments due to the surface roughness of the seal. A complete theoretical analysis of the seal performance is developed to be used as a design tool.Godkänd; 1987; 20070424 (ysko)
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Thiele, Elizabeth Anne. "Culvert Hydraulics: Comparison of Current Computer Models." Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd1727.pdf.
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Krutz, Jill E. "Design of a hydraulic actuator test stand for non-linear analysis of hydraulic actuator systems." Cincinnati, Ohio : University of Cincinnati, 2001. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=ucin990813095.
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Pedersen, Per-Kristian. "Thermal-Hydraulic Analysis of a Pneumatic Resonating Device." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for energi- og prosessteknikk, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-18575.
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Resonator AS is developing a hammer drilling system suitable for oil and geothermal drilling. The nature of the device involves high speed linear motion at high frequencies. As a result of this, the gas springs used in their device are subject to high pressures and temperatures. To prevent pressure leakage from the device, seals are installed.The seals used in the device are fit for use in a limited range of temperatures and pressures. This pose a challenge since a high amount of heat is generated as a result of the friction between the seal and and the gas spring walls.The main objective of this thesis has been to develop a model to investigate the effects of the frictional heat. Control volume techniques have been used to model the effects on the gas pressure and temperature. A detailed heat transfer formulation comprising convection and conduction has been developed. To model the conduction it was necessary to derive two-dimensional heat transfer equations for cylindrical coordinates. A MATLAB-code has been written in order to simulate the behavior of the system.Test results have been compared with the simulations to validate the model. The comparison showed that the model described the thermal inertia of the system appropriately. It also showed that the present friction model is not able to describe the friction in a satisfactory manner.
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Creighton, John Everett. "Thermal hydraulic analysis of hydride fuels in BWR's." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/34443.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 2005.Includes bibliographical references.
This thesis contributes to the hydride nuclear fuel project being completed by UC Berkeley and MIT to assess the possible benefits of using hydride fuel in light water nuclear reactors (LWR's). More specifically, this thesis deals with the thermal hydraulic analysis of BWR reactors. Several papers and theses have already been written for this project, mainly focusing on PWR reactors. The primary goal of this thesis is to find the optimal fuel rod lattice pitch and diameter such that a reactor can safely operate at the highest possible power. This fuel geometry is found out of hundreds of possible choices by using a script to automate a parametric study. A similar process was completed by an MIT graduate student for PWR reactors. While this thesis demonstrates the ability to use such a method for thermal hydraulic BWR analysis, there are some shortcomings which are mainly due to the difficulty of obtaining proprietary information about BWR nuclear reactors. All results hold equally for uranium dioxide as well as hydride fuel since the design limits imposed, critical heat flux, maximum flow velocity and pressure drop constrain only pin array geometry and diameter. It is shown that applicable uranium oxide and hydride fuel limits are both met within the constraints imposed by these three limits which were applied.
(cont.) The final analysis of this report shows a possible reactor power improvement of order 30% but this is based on several analysis selections which introduce error and/or a degree of unrealism into the analysis. First the EPRI critical heat flux correlation was used versus a more appropriate critical power correlation Second the expedient of using a fixed mass flux was adopted which caused the hot channel exit quality to change with power changes. This was done since the means to keep the ratio of reactor power to mass flow rate constant which would have maintained constant exit quality over the geometry map explored by scripting could not be developed in the time available for this work.., Hence definite conclusions on achievable BWR core power over the range of geometries investigated are not available and hence warrant further investigation. More importantly the accomplishment of this thesis is the demonstration that the scripted methodology described in this paper can be used to assess thousands of different reactor parameters in order to optimize reactor power.
by John Everett Creighton.
S.M.
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Alvarado, Blohm Fernando Jose. "Determination of Hydraulic Conductivities through Grain-Size Analysis." Thesis, Boston College, 2016. http://hdl.handle.net/2345/bc-ir:106982.
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Thesis advisor: Alfredo UrzuaThesis advisor: John Ebel
Nine empirical equations that estimate saturated hydraulic conductivity as a func- tion of grain size in well-graded sands with gravels having large uniformity coecients (U > 50) are evaluated by comparing their accuracy when predicting observed conduc- tivities in constant head permeability tests. According to the ndings of this thesis, in decreasing order of accuracy these equations are: USBR (Vukovic and Soro, 1992; USBR, 1978), Hazen (Hazen, 1892), Slichter (Slichter, 1898), Kozeny-Carman (Carrier, 2003), Fair and Hatch (Fair and Hatch, 1933), Terzaghi (Vukovic and Soro, 1992), Beyer (Beyer, 1966), Kruger (Vukovic and Soro, 1992), and Zunker (Zunker, 1932). These re- sults are based on multiple constant head permeability tests on two samples of granular material corresponding to well-graded sands with gravels. Using the USBR equation sat- urated hydraulic conductivities for a statistical population of 874 samples of well-graded sands with gravels forming 29 loads from a heap leaching mine in northern Chile are calculated. Results indicate that, using the USBR equation, on average the hydraulic conductivity of the leaching heaps has a two standard deviation range between 0.18 and 0.15 cm/s. Permeability tests on the actual material used in the heaps provided by the mine shows that the results presented in this thesis are consistent with actual observa- tions and represent saturated conductivities in heaps up to 3 m high under a pressures of up to 62 Kpa. In future work hydraulic conductivities can be combined with water retention curves, discharge rates, irrigation rates, porosities, and consolidation so as to evaluate the relationship between copper yields and the hydraulic conductivities of the heap
Thesis (MS) — Boston College, 2016
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Geology and Geophysics
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Shukla, Amit. "Stability Analysis and Design of Servo-Hydraulic Systems." University of Cincinnati / OhioLINK, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1030385056.
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Keshmiri, Amir. "Thermal-hydraulic analysis of gas-cooled reactor core flows." Thesis, University of Manchester, 2010. https://www.research.manchester.ac.uk/portal/en/theses/thermalhydraulic-analysis-of-gascooled-reactor-core-flows(29335acf-a397-4b8c-8217-fd2ee0d26967).html.
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In this thesis a numerical study has been undertaken to investigate turbulent flow and heat transfer in a number of flow problems, representing the gas-cooled reactor core flows. The first part of the research consisted of a meticulous assessment of various advanced RANS models of fluid turbulence against experimental and numerical data for buoyancy-modified mixed convection flows, such flows being representative of low-flow-rate flows in the cores of nuclear reactors, both presently-operating Advanced Gas-cooled Reactors (AGRs) and proposed ‘Generation IV’ designs. For this part of the project, an in-house code (‘CONVERT’), a commercial CFD package (‘STAR-CD’) and an industrial code (‘Code_Saturne’) were used to generate results. Wide variations in turbulence model performance were identified. Comparison with the DNS data showed that the Launder-Sharma model best captures the phenomenon of heat transfer impairment that occurs in the ascending flow case; v^2-f formulations also performed well. The k-omega-SST model was found to be in the poorest agreement with the data. Cross-code comparison was also carried out and satisfactory agreement was found between the results.The research described above concerned flow in smooth passages; a second distinct contribution made in this thesis concerned the thermal-hydraulic performance of rib-roughened surfaces, these being representative of the fuel elements employed in the UK fleet of AGRs. All computations in this part of the study were undertaken using STAR-CD. This part of the research took four continuous and four discrete design factors into consideration including the effects of rib profile, rib height-to-channel height ratio, rib width-to-height ratio, rib pitch-to-height ratio, and Reynolds number. For each design factor, the optimum configuration was identified using the ‘efficiency index’. Through comparison with experimental data, the performance of different RANS turbulence models was also assessed. Of the four models, the v^2-f was found to be in the best agreement with the experimental data as, to a somewhat lesser degree were the results of the k-omega-SST model. The k-epsilon and Suga models, however, performed poorly. Structured and unstructured meshes were also compared, where some discrepancies were found, especially in the heat transfer results. The final stage of the study involved a simulation of a simplified 3-dimensional representation of an AGR fuel element using a 30 degree sector configuration. The v^2-f model was employed and comparison was made against the results of a 2D rib-roughened channel in order to assess the validity and relevance of the precursor 2D simulations of rib-roughened channels. It was shown that although a 2D approach is extremely useful and economical for ‘parametric studies’, it does not provide an accurate representation of a 3D fuel element configuration, especially for the velocity and pressure coefficient distributions, where large discrepancies were found between the results of the 2D channel and azimuthal planes of the 3D configuration.
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Kvasnica, Tomáš. "Hydraulické posunovače." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2009. http://www.nusl.cz/ntk/nusl-228403.
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This Diploma thesis occupies with design of hydraulic puller. In work are mentioned possible types of construction. Choice construction of puller is disposed with parameters: maximum pushing force 50 kN, speed of piston rod 0,05 m/s. This work also contains FEM analysis by computer programme I-DEAS. The work also occupies with design of fluid drive.
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Kapelan, Zoran. "Calibration of water distribution system hydraulic models." Thesis, University of Exeter, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370011.
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A number of mathematical models are used nowadays to describe behaviour of the reallife water distribution system (WDS). It is a well known fact that, to have any meaningful use, any WDS mathematical model must be calibrated first. Here, calibration is defined as process in which a number of WDS model parameters are adjusted until the model mimics behaviour of the real WDS as closely as possible. In this thesis, WDS mathematical models that are used to model water quantity aspect only are analysed. Three hydraulic models considered here are: (1) steady-state flow model, (2) quasi-steady flow (extended period simulation) model and (3) unsteady flow model. The calibration problem analysed here is formulated as a constrained optimisation problem of weighted least square type with the objective defined in a way that enables effective incorporation of prior information on calibration parameters. WDS calibration problem is then analysed in detail, including special issues of identifiability, uniqueness and stability of the problem solution. A list of diagnostic and other statistics and analysis is presented to improve existing calibration approaches by providing partial insight into the calibration process. Calibration of WDS hydraulic models is further improved by the development of new hybrid optimisation method. Being closely related to calibration, the problem of sampling design for calibration of WDS hydraulic models is also addressed here. First, sampling design is formulated as a constrained two-objective optimisation problem. Then, two novel models are developed to solve it. The first model is based on standard, single-objective Genetic Algorithms (SOGA). The second model is based on multi-objective Genetic Algorithms (MOGA). Finally, all novel methodologies presented here are verified successfully on multiple case studies that involve both artificial and real-life WDS. At the end, relevant conclusions are drawn and suggestions for further research work are made.
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Pingarrón, Alvarez Victoria I. "Performance analysis of hydraulic lime grouts for masonry repair." Connect to PDF file, 2006. http://repository.upenn.edu/cgi/viewcontent.cgi?article=1013&context=hp_theses.
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LEAL, FREDERICO COUTINHO. "NUMERICAL ANALYSIS OF THERMO-HYDRAULIC PROBLEMS IN POROUS MEDIA." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2003. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=3745@1.
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COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIORA dissertação apresenta um estudo da resolução de problemas de acoplamento termo-hidráulico através do uso técnicas numéricas. O estudo tem por objetivo a validação de implementações de efeitos de gradientes de temperatura no fluxo de umidade. Para isto utiliza-se o programa UNSATCHEM- 2D que simula o fluxo bidimensional de umidade em meios de saturação variável, transporte de calor, transporte de CO2 e transporte de solutos. O programa desenvolvido por Simunek e Suarez (1993), possui código aberto (escrito em Fortran 77), onde as equações governantes de fluxo e transporte de calor são resolvidas por elementos finitos. A partir do programa UNSATCHEM-2D, foram realizadas implementações no código a fim de permitir o acoplamento parcial (staggered) do fluxo de umidade e o fluxo de calor que reproduz o fenômeno descrito por de Vries (1958). Paralelamente, desenvolveram-se mudanças no programa MTool(Tecgraf/PUC- Rio), utilizado como pré- e pós-processador. Posteriormente, foram validadas as implementações realizadas no programa comparando-se os resultados da solução numérica com resultados experimentais a partir de um ensaio de coluna (Bach, 1989), com resultados considerados satisfatórios. Finalizando, são apresentadas simulações com fontes de calor interna e externa paralelamente com o emprego de condições de contorno atmosféricas que simulam coberturas de resíduos de minério.
The dissertation presents a study of the resolution of thermo-hydraulic coupling problems, through the use of numerical techniques. The study has the objective the implementations validation of the temperature gradients effects in the moisture flux. For this, the program UNSATCHEM-2D is used to simulate the flow of water in mediums of variable saturation to two dimensions, transport of heat, transport of CO2 and solute transport. The program developed by Simunek and Suarez (1993), has open code (written in Fortran 77), where the governing equations of flow and transport of heat are solved for the method of the finite elements. Starting from the original program UNSATCHEM-2D, alterations were carried out in the code in order to allow the partial coupling (staggered) of moisture flow and heat flow as described by de Vries (1958). In parallel, changes were developed in the software MTool (Tecgraf/PUC-Rio), used as pre- and posprocessor. Later, the modifications carried out in the program were validated by the comparison of the numeric solution results with experimental results starting from a column test (Bach, 1989), with acceptable results. Concluding, simulations are presented with internal and external sources of heat together with the use of atmospheric boundary conditions, one that simulates covers for mining wastes.
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BRAGA, CARLOS VALOIS MACIEL. "THERMAL HYDRAULIC ANALYSIS OF SMOOTH AND FINNED ANNULAR DUCTS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 1987. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=20502@1.
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CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFINANCIADORA DE ESTUDOS E PROJETOS
O presente trabalho analisa a transferência de calor e a perda de carga em escoamento turbulento através das regiões anulares lisas e aletadas. Os coeficientes de transferência de calor foram obtidos experimentalmente, utilizando-se a teoria de trocadores de calor. Também foram determinados os coeficientes de perda de carga associados a cada uma das geometrias analisadas. Os experimentos foram realizados em um trocador de calor bi-tubular concêntrico. Água (fluído quente) escoava através do tubo interno, enquanto ar (fluido frio) fluía através da região anular. Medindo-se as vazões e temperaturas na entrada e saída da seção de teste do trocador de calor, obtém-se a efetividade da mesma e, consequentemente, o coeficiente global de transferência de calor (médio). As condições de contorno adotadas foram de temperatura uniforme na superfície externa do tubo interno e de isolamento térmico na superfície externa do tubo interno e de isolamento térmico na superfície externa da região anular. Com o objetivo de obter-se condições de escoamento completamente desenvolvido, o trocador de calor possui um comprimento, a montante da seção de testes, de aproximadamente trinta diâmetros hidráulicos. Os coeficientes de transferência de calor e de perda de carga são apresentados de forma adimensional, como função do número de Reynolds do escoamento, os resultados obtidos para as regiões anulares lisas e aletadas são comparados entre si. O propósito de tal comparação foi o de estudar a influencia das aletas na perda de carga e na taxa de transferência de calor. No caso das regiões aletadas, verifica-se que a eficiência das aletas influencia a transferência de calor. Deste modo, realizou-se uma análise bi-dimensional de transferência de calor nas aletas para obter-se a eficiência das mesmas e, consequentemente, a eficiência das regiões aletadas. Também é mostrado que o desempenho térmico da região depende principalmente do número de Nusselt e da eficiência da mesma. Tais parâmetros são apresentados, em última análise, como funções do número de Reynolds e da geometria do problema.
The present work is concerned with the turbulent heat transfer and pressure drop in smooth and finned annular ducts. Average heat transfer coeeficients have been obtained by means of the heat exchanger theory. In addition, friction factors have also been determined. The experiments were performed by utiling four double-pipe heat exchangers. The average heat transfer coefficients, for air flowing in the annular section, were fertmined by measuring the overall heat transfer coefficients of the heat exchangers. In order to aatain fully developed conditions, the heat exchangers had a starting length of 30 hydrualic diameters. The thermal boundary conditions consisted of uniform temperature on the inner surface, the outer surface being insulate. The heat transfer coefficients and friction factors are presented in dimensinless forms, as functions of the Reynolds number of the fow. The results for smooth and finned annular ducts were compared. The purpose of such comparison was to study the influence of the fins on the pressure drop and heat transfer rate. In the case of the finned annular ducts, it is shown that fin efficiency has some influence on the heat transfer rates. Then a two-dimensional heat transfer analysis was performed in order to obtain the fin efficiency and the annular region efficiency. It is also shown that the overall thermal performance of finned surfaces depends mainly of the Nusselt number and on the region efficiency. These parameters are presented as functiond of the Reynolds number of the flow and the geometry of the problem.
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Ferroni, Paolo Ph D. Massachusetts Institute of Technology. "Steady state thermal hydraulic analysis of hydride fueled BWRs." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/41263.
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Includes bibliographical references (p. 205-208).Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Nuclear Science and Engineering, 2006.
(cont.) Since the results obtained in the main body of the analysis account only for thermal-hydraulic constraints, an estimate of the power reduction due to the application of neutronic constraints is also performed. This investigation, focused only on the "New Core" cases, is coupled with an increase of the thickness of the gap separating adjacent bundles from 2 to 5 mm. Under these more conservative conditions, the power gain percentages are lower, ranging between 24% and 43% (depending on the discharge burnup considered acceptable) for the upper pressure drop limit, and between 17% and 32% for the lower pressure drop limit.
(cont.) The benefits of the latter approach are evident since the space occupied by the bypass channel for cruciform control rod insertion becomes available for new fuel and a higher power can be achieved. The core power is constrained by applying thermal-hydraulic limits that, if exceeded, may induce failure mechanisms. These limits concern Minimum Critical Power Ratio (MCPR), core pressure drop, fuel average and centerline temperature, cladding outer temperature and flow-induced vibrations. To limit thermal-hydraulic instability phenomena, core power and coolant flow are constrained by fixing their ratio to a constant value. In particular, each BWR/5 core has been analyzed twice, each time with a different pressure drop limit: a lower limit corresponding to the pressure drop of the reference core and an upper limit 50% larger. It has been demonstrated that, in absence of neutronic constraints and with the maximum allowed pressure drop fixed at the upper limit, the implementation of the hydride fuel yields power gain percentages, with respect to oxide cores chosen as reference, of the order of 23% when its implementation is performed following the "Backfit" approach and even higher (50-70%) when greater design freedom is allowed in the core design, i.e. in the "New Core" approach. Should the maximum allowed pressure drop be fixed at the lower limit, the power gain percentage of the "Backfit" approach would decrease to 17%, while that of the "New Core" approach would remain unchanged, i.e. 50-70%.
This thesis contributes to the Hydride Fuel Project, a collaborative effort between UC Berkeley and MIT aimed at investigating the potential benefits of hydride fuel use in Light Water Reactors (LWRs). Considerable work has already been accomplished on hydride fueled Pressurized Water Reactor (PWR) cores. This thesis extends the techniques used in the PWR analysis to examine the potential power benefits resulting from the implementation of the hydride fuel in Boiling Water Reactors (BWRs). This work is the first step towards the achievement of a complete understanding of the economic implications that may derive from the use of this new fuel in BWR applications. It is a whole core steady-state analysis aimed at comparing the power performance of hydride fueled BWR cores with those of typical oxide-fueled cores, when only thermal-hydraulic constraints are applied. The integration of these results with those deriving from a transient analysis and separate neutronic and fuel performance studies will provide the data required to build a complete economic model, able to identify geometries offering the lowest cost of electricity and thus to provide a fair basis for comparing the performance of hydride and oxide fuels. Core design is accomplished for two types of reactors: one smaller, a BWR/5, which is representative of existing reactors, and one larger, the ESBWR, which represents the future generation of BWRs. For both, the core design is accomplished in two ways: a "Backfit" approach, in which the ex-bundle core structure is identical to that of the two reference oxide cores, and a "New Core" approach, in which the control rods are inserted into the bundles in the form of control fingers and the gap between adjacent bundles is fixed optimistically at 2 mm.
by Paolo Ferroni.
S.M.
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Quinn, Timothy Sean. "Experimental analysis of permeability barriers to hydraulic fracture propagation." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/34076.
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BOGRAD, SERGIY. "APPLICATION OF THE TRANSFER PATH ANALYSIS TO HYDRAULIC SYSTEMS." University of Cincinnati / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1109277506.
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Sholtes, Joel Doyle Martin W. "Hydraulic analysis of stream restoration on flood wave propagation." Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2009. http://dc.lib.unc.edu/u?/etd,2523.
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Thesis (M.A.)--University of North Carolina at Chapel Hill, 2009.Title from electronic title page (viewed Oct. 5, 2009). "... in partial fulfillment of the requirements for the degree of Master of Arts in the Department of Geography." Discipline: Geography; Department/School: Geography.
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SALAM, AL HINAI SAIF SAID. "PRACTICAL ANALYSIS OF RIVER FLOWS AROUND SELECTED HYDRAULIC STRUCTURES." 京都大学 (Kyoto University), 2011. http://hdl.handle.net/2433/142195.
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KHOLIA, AKSHAT. "Thermal Hydraulic numerical analysis of Fusion superconducting magnet systems." Doctoral thesis, Politecnico di Torino, 2013. http://hdl.handle.net/11583/2507886.
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In the present scenario, the International Thermonuclear Experimental Reactor (ITER) is in progress and efforts are being made to extend ITER to DEMOnstration Power plant (DEMO) with the purpose to harness the fusion energy for peaceful and constructive purposes. ITER uses the sueperconducting magnet systems for trapping and maneuvering plasma inside the giant tokamak machines. Superconductivity only entails under the critical conditions of temperature, magnetic field and current density. If any of these parameters surpass the critical value, the quench ensues in the cable. In the real system scenarios, electromagnetic, radiative & conductive loads are present, which may affect the performance of the machine. The magnet designer can change the parameters in terms of current and magnetic field to ensure that the critical conditions
are met, but when it comes to temperature, it is really hard to locate the hot spot locations. To envisage such situations, it is essential to study thermal hydraulics and hence system code is needed for the whole superconducting magnet system. For such purposes, Cryogenic Circuit, Conductor and Coil code (4C) was built, imbibing the thermal hydraulic modeling of the cable in Conduit conductors (including strands) coupled with structures (which give support to the
winding pack, wound by conductors) and an external cryogenic circuit.
During the thesis work, the pre-existing 4C code, was modeled for various coils with or without external cooling circuit as required. Henceforth, it was implemented against the wide range of transients, fast transients (~ few seconds) as well as slow transients (~ few days or weeks) to test the flexibility of the code in studying the wide range of physical phenomenon on different time scales. Eventually, the results were validated against the available experimental data to observe the precision of the model in 4C code. One of the analysis carried out during this dissertation included the cool down of one of the non planar coils (NPC) used in Wendelstein 7-X, which was an example of slow transient. In the domain of fast transients, an extensive analysis of AC losses in one of poloidal field (PF) coils with an external cooling circuit, was performed for Korean Superconducting Tokamak Advanced Research (KSTAR), functional
fusion device.
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Watson, C. "A finite element analysis of a 'S' cam brake." Thesis, Loughborough University, 1991. https://dspace.lboro.ac.uk/2134/6757.
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An analysis of a commercial vehicle drum brake fitted with a typical asbestos free friction material has been investigated by the finite element method. The "GAPFRIC" concept has been extended to model in three dimensions the frictional interface between brake linings and drum. This approach incorporates an accurate representation of the brake itself to include such features as the brake drum stiffener and mounting flange. The brake shoe representations include the actual web and platform thus eliminating the need for shoe stiffness approximations to a curved beam of uniform section as used in previous two dimensional work. The mechanical "GAPFRIC" analysis is combined with a thermal analysis of the brake to form a brake analysis package. The package is fully automatic; the output from each stage of the analysis is post processed and the results used to modify the original data file. Variations in physical properties exist between new and used friction material and these are incorporated in a five phase idealisation of the friction pair. Modifications to allow for the change of coefficient of friction with temperature were made by means of tables within the coding. In addition friction material wear was included in the analyses using an empirically derived wear criteria. Analyses were completed to investigate the effect of combined axial and circumferential distortions on temperatures at the friction interface, interfacial pressure distributions and subsequent brake performance. Predicted results show that high temperatures are reached at certain regions on the rubbing path and the temperatures may fluctuate during a brake application. Pressure variations are seen to exist both around and across the surface of the linings. The coupling of pressure and temperature variations combined with frictional changes over the lining produce changes that result in the frictional drag per unit area tending to be reasonably constant over the interface between drum and lining. The predicted values of brake torque and brake factor f rom the three dimensional analyses have been compared with results derived f rom the earlier two dimensional brake analysis and validated by comparison with measured results from a brake mounted on a dynamometer. Similarly predicted brake drum and lining temperatures were compared with measured values and some reasonable trends established. The work itself presents a better physical description of the behaviour at the friction surface during braking to improve the determination of brake drum performance.
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Pavelka, Roman. "Hydraulické posunovače." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2011. http://www.nusl.cz/ntk/nusl-229740.
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This diploma thesis deals with the mechanical proposal of hydraulic puller. Furthermore, it includes the detail design solutions. The project also includes the calculation of the hydraulic puller parameters: maximum pushing force is 60 kN, speed of movement is 0.1 m s-1. This work also contains of stress analysis FEM with I-DEAS software. Following part deals with the design of hydraulic circuit for driving puller. At the end of work there are options for replacements of hydraulic puller by mechanical systems.
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Zafirakou, Antigoni Koulouris. "Statistical analysis techniques in water resources engineering /." Thesis, Connect to Dissertations & Theses @ Tufts University, 2000.
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Thesis (Ph. D.)--Tufts University, 2000.Adviser: Richard M. Vogel. Submitted to the Dept. of Civil and Environmental Engineering. Includes bibliographical references (leaves 206-214). Access restricted to members of the Tufts University community. Also available via the World Wide Web;
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Smemoe, Christopher M. "Floodplain Risk Analysis Using Flood Probability and Annual Exceedance Probability Maps." Diss., CLICK HERE for online access, 2004. http://contentdm.lib.byu.edu/ETD/image/etd379.pdf.
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Tuddenham, Read Stapley. "Thermal hydraulic analysis of a packed bed reactor fuel element." Thesis, Monterey, California. Naval Postgraduate School, 1989. http://hdl.handle.net/10945/26300.
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GUIMARAES, GLAUCE DA SILVA. "ANALYSIS OF THE RHEOLOGICAL CHARACTERISTICS OF A HYDRAULIC FRACTURING FLUID." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 1989. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=33266@1.
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Como parte da linha de pesquisa na área de estimulação de poços de petróleo, foi montado um viscosímetro tubular para análise das características de comportamento reológico de um fluido de fraturamento hidráulico (HPGUAR), dotado de dispositivo para preparação do fluido . Os dados experimentais obtidos foram tratados analiticamente segundo dois tipos de equações constitutivas: as do Modelo de Ostwald, amplamente utilizadas pelos pesquisadores da área de Engenharia de Petróleo, e as do Modelo de Bingham. Pela avaliação dos resultados obtidos, pode-se concluir que parecem ocorrer evidências de que o Modelo de Bingham possa ser mais adequado, por retratar de forma mais independente as contribuições isoladas do atrito viscoso e da componente gerada pela viscosidade plástica, na análise teológica do HPGUAR. Sugere-se que investigações mais detalhadas devam ser conduzidas, posto que eventualmente poderiam ser bastante úteis no esclarecimento da pendência existente nos resultados experimentais obtidos por diversos autores consultados.In order to contribute in the investigation of the stimulation operation of an oil reservoir was built a tubular viscometer to determine the rheological properties of a hydraulic fracturing fluid (HPGUAR). This test rig included a system to prepare the hydraulic fracturing fluid. The experimental results were modelled according to two types of constitutive equations: the Ostwald Model one, widely used in the Petroleum Engineers field, and the Bingham Model one. An evaluation of the experimental results suggests that the Bingham Model should be more adequate than the other one, specifically when it shows the contribuition from the viscous friction and from the plastic viscosity independently, in the determination of the rheological properties of the HPGUAR. More detailed investigations must be carried out, although they should be very usefull in better explaning the differeces obtained among several investigators.
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Ijadi-Maghsoodi, Sonia. "An analysis of the hydraulic conveying of coarse particle slurries." Thesis, Imperial College London, 1988. http://hdl.handle.net/10044/1/47119.
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Van, Heerden George Adrian. "Evaluation of alternatives for hydraulic analysis of sanitary sewer systems." Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/86534.
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Thesis (MScEng)--Stellenbosch University, 2014.ENGLISH ABSTRACT: This research project focuses on sanitary sewer systems. When performing an analysis of a sewer drainage system with known constraints, an appropriate model needs to be chosen depending on the objectives of the analysis. Uncertainties are also present in the analysis of sewer drainage systems. The uncertainties and the errors in hydraulic models need to be understood and considered. The required level of accuracy and the type of hydraulic problem that needs to be solved may alter the complexity of the hydraulic model used to solve a drainage system. The wide variety of available simulation models further complicates model selection. With various models available, selecting the most appropriate model for a particular drainage system simulation is important. The various models for sewer drainage system analysis can be categorised in different ways. For example, it is possible to categorise models according to their purpose, which could be evaluation, design or planning. Evaluation models are mainly used to test whether existing systems or planned systems are adequate and require the highest hydraulic detail. Design models are used to determine the size of conduits within a drainage system and require moderate levels of hydraulic detail. Planning models are primarily used for strategic planning and decision making for urban or regional drainage systems and require the least amount of hydraulic detail. An understanding of the available models is required in order to choose the most suitable simulation model for the desired purpose. Some models are derived from the Saint-Venant equations of flow. The most detailed models are typically referred to as fully dynamic wave models and utilise all the components of the Saint-Venant flow equations. By removing terms from the Saint-Venant equations a kinematic wave model can be created. Some less complex models ignore basic principles of hydraulics in order to make assumptions that simplify the process of simulating flows. In this thesis three different models were compared: a detailed model using fully dynamic flow equations, a simplified model using kinematic wave equations and a basic model using contributor hydrograph routing equations. For the drainage system analysis SWMM-EXTRAN was used as the fully dynamic wave model, SWMM-TRANSPORT was used as the kinematic wave model and SEWSAN was used as the contributor hydrograph model. Two drainage systems situated in South Africa were used as case studies and are referred to as Drainage System A and Drainage System B in this thesis. The actual flow rate was recorded at two points with flow loggers, one in each of the two systems. The flow rate was continually recorded at 1 hour intervals for the period 1 July 2010 to 9 July 2010 in Drainage System A as well as in Drainage System B. The same input parameters were used for each model allowing the modelled flow rates to be compared to the measured flow rates. The models provided peak flow results that were within 2% of the measured peak flow rates and the modelled mean flows were within 8.5% of the measured mean flows in most situations. However, when rapidly varied flows occurred the kinematic wave and contributor hydrograph models returned conservative results as they were unable to account for hydraulic effects such as acceleration. The effect of acceleration became most pronounced up and downstream of drop structures and sections where the slope changed considerably. The kinematic wave and contributor hydrograph models were therefore unable to accurately simulate surcharge conditions. The results suggest that the fully dynamic wave model can be used in all scenarios. The kinematic wave model can be used for a design analysis if no hydraulic structures occur in the system. The contributor hydrograph model should not be used for an evaluation analysis, but can be used for a design analysis if a relatively high level of confidence in the parameter set exists and no areas of rapidly varying flow or hydraulic structures exist within the system.
AFRIKAANSE OPSOMMING: Hierdie navorsing projek is gefokus op riool dreineringsisteme. Wanneer ʼn analise van ʼn riool dreineringsisteem met bekende beperkinge onderneem word, moet ʼn geskikte model gekies word afhangende van die doelwitte van die analise. Onbekendes is ook teenwoordig in die analise van riool dreineringsisteme. Dit word belangrik dat die onsekerhede en die foute in hidroliese modelle moet verstaan en oorweeg word. Die verwagte vlak van akkuraatheid en die tipe hidroliese probleem wat opgelos moet word mag die ingewikkeldheid van die hidroliese probleem, wat gebruik word om ʼn rioolsisteem op te los, verander. Die wye verskeidenheid van beskikbare simulasie modelle bemoeilik verder die keuse van ʼn model. Met etlike modelle beskikbaar vir seleksie, is die mees geskikte model vir ʼn spesifieke dreineringsisteem simulasie belangrik. Die verskeie modelle vir riool dreineringsisteem analise kan op verskillende wyses gekategoriseer word. Byvoorbeeld, dit is moontlik om modelle te kategoriseer volgens hulle doel, wat evaluasie, ontwerp en beplanning kan wees. Evaluasiemodelle word hoofsaaklik gebruik om te toets of huidige of beplande sisteme voldoende is en of hulle die hoogs moontlike hidroliese besonderhede benodig. Ontwerpmodelle word gebruik om die grootte van ʼn leipyp binne ʼn rioolsisteem te bepaal en benodig matige vlakke van hidroliese besonderhede. Beplanningsmodelle word hoofsaaklik gebruik vir strategiese beplanning en besluitneming vir stedelike en landelike rioolsisteme en benodig die laagste vlak van hidroliese data. ʼn Begrip van die beskikbare modelle is nodig om ʼn keuse te maak rakende die mees geskikte simulasie model vir die verlangde doelwit. Sommige modelle is afkomstig van die Saint-Venant vergelykings van vloei. Die mees gedetailleerde modelle word tipies na verwys as die volledige dinamiese golf modelle en benut alle komponente van die Saint-Venant vloei vergelykings. Deur die verwydering van terme van die Saint-Venant vergelykings kan ʼn kinematiese golf model daargestel word. Sommige minder gekompliseerde modelle ignoreer die basiese beginsels van hidrologie om aannames te maak wat die proses van golf simulering vereenvoudig. In hierdie tesis is drie verskillende modelle vergelyk; ʼn gedetailleerde model wat volledige dinamiese vloeivergelykings gebruik; ʼn vereenvoudigde model wat kinematiese golfvergelykings gebruik en ʼn basiese model wat bydraende hidroliese versending vergelykings. Vir die dreineringsisteem analise was SWMM-EXTRAN gebruik as die volledige dinamiese golfmodel, SWMM-TRANSPORT was gebruik as die kinetiese golfmodel en SEWSAN was gebruik as die bydraende hidroliese model. Twee dreineringsisteme in Suid-Afrika was gebruik as gevallestudies en word na verwys as Dreineringsisteem A en Dreineringsisteem B. Die werklike vloeikoers was aangeteken by twee punte met vloeimeters, een in elk van die sisteme. Die vloeikoers was deurlopend opgeteken met 1 uur tussenposes vir die periode 1 Julie 2010 tot 9 Julie 2010 in Dreinering Sisteem A sowel as Dreinering Sisteem B. Dieselfde inset parameters was gebruik vir elke model wat dit moontlik gemaak het dat die gemoduleerde vloeikoerse met die gemete vloeikoerse vergelyk kon word. Die modelle het spits vloeiresultate voorsien wat binne 2% van die gemete spits vloeikoerse was en, in die meeste situasies, dat die gemoduleerde gemiddelde vloei binne 8.5% van die gemete gemiddelde vloei was. Wanneer vinnig varierende vloei voorgekom het, die kinetiese golf and bydraende hidrograaf modelle konserwatiewe resultate gelewer het, aangesien hulle nie in staat was om hidroliese effekte soos versnelling te verklaar nie. Die effek van versnelling was op sy duidelikste stroomopwaarts en stroomafwaarts onder valstrukture en by gedeeltes waar die helling aansienlik verander het. Die kinetiese golf en bydraer hidrograaf modelle was gevolglik nie in staat om oorladingsomstandighede akkuraat te simuleer nie. Die resultate wys dat die volledige dinamiese vloeimiddel gebruik kan word in alle omstandighede. Die kinematiese vloeimiddel kan gebruik word vir ʼn ontwerp analise indien geen hidroliese struktuur in die sisteem voorkom nie. Die bydraer hidrograaf model behoort nie gebruik te word vir ʼn evaluerings analise nie, maar kan gebruik word vir ʼn ontwerp analise indien ʼn relatiewe hoë vlak van vertroue in die parameter stel bestaan en geen area van vinnig veranderende vloei of hidroliese strukture binne die sisteem bestaan nie.
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Constantino, Carlos Augusto. "Hydraulic actuation system modeling: an analysis of high frequency modeling." Instituto Tecnológico de Aeronáutica, 2010. http://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=1307.
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The objective of this work was to develop a high fidelity model representative up to high frequencies of a Flight Control System with hydraulic actuation on active-active mode. The usage of a Fly-By-Wire architecture and hydraulic actuation system on active-active mode has brought new engineering challenges like the force-fight between actuators and its structure fatigue life consumption on normal and failure scenarios such as oscillatory mal-functions. Once that these failure modes can exist up to high frequencies, it makes necessary the development of a high fidelity model of a flight control system representative up to high frequencies. The model herein developed has a high fidelity model of an EHSV, hydraulic actuator, a position loop and the control surface, as well as other models complementary in order that it can be possible to analyze the whole system up to high frequencies. It was analyzed the performance of the model at step input response and frequency response, showing to be a model close to the expected response of a real system. Also it was analyzed the frequency response of its components showing to be a representative model up to high frequencies. Besides the performance analysis, it was studied the behavior on a oscillatory mal-function scenario, showing the expected level of structure load, as well as its fatigue life consumption, showing the need to monitor these types of failures.
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KOWTA, SRINIVAS. "ROBUST STABILITY ANALYSIS OF SERVO-HYDRAULIC SYSTEM IN PARAMETER SPACE." University of Cincinnati / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1060970575.
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Fredette, Luke. "Dynamic Analysis of Fractionally-Damped Elastomeric and Hydraulic Vibration Isolators." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1479904009913121.
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Pullinger, Michael. "Evaluating hydraulic transient analysis techniques in pumped-storage hydropower systems." Thesis, Pullinger, Michael (2011) Evaluating hydraulic transient analysis techniques in pumped-storage hydropower systems. Masters by Coursework thesis, Murdoch University, 2011. https://researchrepository.murdoch.edu.au/id/eprint/5819/.
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Hydropower is the most widely adopted form of renewable energy in the world today, accounting for approximately 16% of global energy production [1]. With increasing demand for electricity, and concern about reducing fossil fuel consumption, hydropower is likely to continue to play a key role in global energy production. The interest in pumped-storage systems is increasing, due to their ability to regulate power grids, increase the efficiency of thermal power (coal and nuclear), and maximise the penetration of renewable energy such as wind and solar. Since pumped-storage systems must respond quickly to load variations, transient flow phenomena are frequent. In the design of hydropower systems, transient effects are an important consideration, as rapid flow variations can lead to potentially catastrophic increases in pressure (water-hammer). Numerical techniques for hydraulic transient analysis appear to be well understood, but the hydraulic characteristics of reversible pump-turbines can create difficulties depending on the software used for the analysis. The “S” shape of the machine characteristic in the turbine runaway region is a cause of instability in real machines and a potential cause of numerical instability in incorrectly designed or unsuitable software packages. The commercial hydraulic analysis software package SIMSEN-Hydro was used to evaluate hydraulic transients in two systems. Project A is a 25.5 MW run of river system utilising three Francis turbines. Hydraulic transients in the system were successfully modelled, and the results showed good agreement with load rejection data measured on site during commissioning of the project. Project B is a 1333 MW pumped-storage system utilising four reversible Francis pump-turbines. The machine curves include the characteristic “S” shape in the runaway region of the turbine zone. Using SIMSEN-Hydro, the transients in the system were modelled, utilising the machine characteristics. Results were similar to those obtained during preliminary design of the system. By undertaking a sensitivity analysis for Project B, the effect of modifying input parameters on the simulation results was highlighted. The choice of pipe friction factor, surge tank throttling coefficient and generator inertia all had a notable effect on the results of the analysis. While the range of pressure wave-speeds that were examined did not have a significant effect on the results, this may differ for other systems. Based on these results, it seems important that sensitivity analysis be included on all transient analysis projects, unless the modelling inputs are all known with a reasonable level of accuracy.
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Minasny, Budiman. "Efficient Methods for Predicting Soil Hydraulic Properties." Thesis, The University of Sydney, 2000. http://hdl.handle.net/2123/853.
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Both empirical and process-simulation models are useful for evaluating the effects of management practices on environmental quality and crop yield. The use of these models is limited, however, because they need many soil property values as input. The first step towards modelling is the collection of input data. Soil properties can be highly variable spatially and temporally, and measuring them is time-consuming and expensive. Efficient methods, which consider the uncertainty and cost of measurements, for estimating soil hydraulic properties form the main thrust of this study. Hydraulic properties are affected by other soil physical, and chemical properties, therefore it is possible to develop empirical relations to predict them. This idea quantified is called a pedotransfer function. Such functions may be global or restricted to a country or region. The different classification of particle-size fractions used in Australia compared with other countries presents a problem for the immediate adoption of exotic pedotransfer functions. A database of Australian soil hydraulic properties has been compiled. Pedotransfer functions for estimating water-retention and saturated hydraulic conductivity from particle size and bulk density for Australian soil are presented. Different approaches for deriving hydraulic transfer functions have been presented and compared. Published pedotransfer functions were also evaluated, generally they provide a satisfactory estimation of water retention and saturated hydraulic conductivity depending on the spatial scale and accuracy of prediction. Several pedotransfer functions were developed in this study to predict water retention and hydraulic conductivity. The pedotransfer functions developed here may predict adequately in large areas but for site-specific applications local calibration is needed. There is much uncertainty in the input data, and consequently the transfer functions can produce varied outputs. Uncertainty analysis is therefore needed. A general approach to quantifying uncertainty is to use Monte Carlo methods. By sampling repeatedly from the assumed probability distributions of the input variables and evaluating the response of the model the statistical distribution of the outputs can be estimated. A modified Latin hypercube method is presented for sampling joint multivariate probability distributions. This method is applied to quantify the uncertainties in pedotransfer functions of soil hydraulic properties. Hydraulic properties predicted using pedotransfer functions developed in this study are also used in a field soil-water model to analyze the uncertainties in the prediction of dynamic soil-water regimes. The use of the disc permeameter in the field conventionally requires the placement of a layer of sand in order to provide good contact between the soil surface and disc supply membrane. The effect of sand on water infiltration into the soil and on the estimate of sorptivity was investigated. A numerical study and a field experiment on heavy clay were conducted. Placement of sand significantly increased the cumulative infiltration but showed small differences in the infiltration rate. Estimation of sorptivity based on the Philip's two term algebraic model using different methods was also examined. The field experiment revealed that the error in infiltration measurement was proportional to the cumulative infiltration curve. Infiltration without placement of sand was considerably smaller because of the poor contact between the disc and soil surface. An inverse method for predicting soil hydraulic parameters from disc permeameter data has been developed. A numerical study showed that the inverse method is quite robust in identifying the hydraulic parameters. However application to field data showed that the estimated water retention curve is generally smaller than the one obtained in laboratory measurements. Nevertheless the estimated near-saturated hydraulic conductivity matched the analytical solution quite well. Th author believes that the inverse method can give a reasonable estimate of soil hydraulic parameters. Some experimental and theoretical problems were identified and discussed. A formal analysis was carried out to evaluate the efficiency of the different methods in predicting water retention and hydraulic conductivity. The analysis identified the contribution of individual source of measurement errors to the overall uncertainty. For single measurements, the inverse disc-permeameter analysis is economically more efficient than using pedotransfer functions or measuring hydraulic properties in the laboratory. However, given the large amount of spatial variation of soil hydraulic properties it is perhaps not surprising that lots of cheap and imprecise measurements, e.g. by hand texturing, are more efficient than a few expensive precise ones.
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Minasny, Budiman. "Efficient Methods for Predicting Soil Hydraulic Properties." University of Sydney. Land, Water & Crop Sciences, 2000. http://hdl.handle.net/2123/853.
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Both empirical and process-simulation models are useful for evaluating the effects of management practices on environmental quality and crop yield. The use of these models is limited, however, because they need many soil property values as input. The first step towards modelling is the collection of input data. Soil properties can be highly variable spatially and temporally, and measuring them is time-consuming and expensive. Efficient methods, which consider the uncertainty and cost of measurements, for estimating soil hydraulic properties form the main thrust of this study. Hydraulic properties are affected by other soil physical, and chemical properties, therefore it is possible to develop empirical relations to predict them. This idea quantified is called a pedotransfer function. Such functions may be global or restricted to a country or region. The different classification of particle-size fractions used in Australia compared with other countries presents a problem for the immediate adoption of exotic pedotransfer functions. A database of Australian soil hydraulic properties has been compiled. Pedotransfer functions for estimating water-retention and saturated hydraulic conductivity from particle size and bulk density for Australian soil are presented. Different approaches for deriving hydraulic transfer functions have been presented and compared. Published pedotransfer functions were also evaluated, generally they provide a satisfactory estimation of water retention and saturated hydraulic conductivity depending on the spatial scale and accuracy of prediction. Several pedotransfer functions were developed in this study to predict water retention and hydraulic conductivity. The pedotransfer functions developed here may predict adequately in large areas but for site-specific applications local calibration is needed. There is much uncertainty in the input data, and consequently the transfer functions can produce varied outputs. Uncertainty analysis is therefore needed. A general approach to quantifying uncertainty is to use Monte Carlo methods. By sampling repeatedly from the assumed probability distributions of the input variables and evaluating the response of the model the statistical distribution of the outputs can be estimated. A modified Latin hypercube method is presented for sampling joint multivariate probability distributions. This method is applied to quantify the uncertainties in pedotransfer functions of soil hydraulic properties. Hydraulic properties predicted using pedotransfer functions developed in this study are also used in a field soil-water model to analyze the uncertainties in the prediction of dynamic soil-water regimes. The use of the disc permeameter in the field conventionally requires the placement of a layer of sand in order to provide good contact between the soil surface and disc supply membrane. The effect of sand on water infiltration into the soil and on the estimate of sorptivity was investigated. A numerical study and a field experiment on heavy clay were conducted. Placement of sand significantly increased the cumulative infiltration but showed small differences in the infiltration rate. Estimation of sorptivity based on the Philip's two term algebraic model using different methods was also examined. The field experiment revealed that the error in infiltration measurement was proportional to the cumulative infiltration curve. Infiltration without placement of sand was considerably smaller because of the poor contact between the disc and soil surface. An inverse method for predicting soil hydraulic parameters from disc permeameter data has been developed. A numerical study showed that the inverse method is quite robust in identifying the hydraulic parameters. However application to field data showed that the estimated water retention curve is generally smaller than the one obtained in laboratory measurements. Nevertheless the estimated near-saturated hydraulic conductivity matched the analytical solution quite well. Th author believes that the inverse method can give a reasonable estimate of soil hydraulic parameters. Some experimental and theoretical problems were identified and discussed. A formal analysis was carried out to evaluate the efficiency of the different methods in predicting water retention and hydraulic conductivity. The analysis identified the contribution of individual source of measurement errors to the overall uncertainty. For single measurements, the inverse disc-permeameter analysis is economically more efficient than using pedotransfer functions or measuring hydraulic properties in the laboratory. However, given the large amount of spatial variation of soil hydraulic properties it is perhaps not surprising that lots of cheap and imprecise measurements, e.g. by hand texturing, are more efficient than a few expensive precise ones.
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Asif, Ehsan Syed Mortuza. "Three Essays on the Economics of Hydraulic Fracturing." Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/72130.
Full textAbstract:
Hydraulic fracturing has been increasingly used in the USA to economically extract natural
gas and oil from newly discovered shale plays. Despite new, more severe, and long term
impacts of hydraulic fracturing compared to conventional drilling, regulatory practices are
mostly implemented by states that regulate with older regulations that were were written
before the widespread use of hydraulic fracturing. This dissertation presents three essays on
the economics of hydraulic fracturing. A standard renewable lease in hydraulic fracturing
runs for a five-year primary term. The first essay examines the effect of initial contract length
on extraction behavior and social costs. It finds that the rate of extraction decreases over
time for both, the social planner and the private extractor. In addition, the social planner
has a more stable extraction path compared to the private extractor. Holding other things
equal, if the social planner seeks to induce a private extractor to leave a higher in situ stock
un-extracted, then the optimal contract duration is longer. Simulations illustrate the magnitude
of social costs inherent in hydraulic fracturing and non-optimal fixed contract lengths. The second essay investigates the impact of the significantly increased bonding requirements
for horizontal wells introduced in West Virginia in December, 2011, on the probability of
violation committed by those wells. Results suggest that the increased bonding requirement
has reduced the probability of violation by 2.6 to 3.2 percentage points. Moreover, it slightly
reduces the number of violations done by horizontal wells. Finally, the third essay explores
several aspects of Act-13, introduced on February 14, 2012, by Pennsylvania. This act imposes new fees that are assessed annually for fifteen years, on all unconventional gas wells in Pennsylvania. This chapter explores the impacts of Act-13 on the likelihood of an unconventional well's shut-down, rate of extraction, and probability of violation. Results suggest that wells incurring this increased fee schedule have a significantly higher likelihood (more than three times) of shut-down. Also, Act-13 have reduced the extraction rate, and the probability of violation committed by unconventional wells in Pennsylvania.Ph. D.
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Cazaban, Philip M. "Experimental Analysis of the Flow, Pressure, Speed, and Torque Characteristics of Two Eaton Geroler Hydraulic Motors." University of Akron / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=akron1312124231.
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Dillin, Matthew F. "Wavelet analysis of the spatial variability of hydraulic conductivity on hydraulic head." Thesis, 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1464492.
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Liu, Yen-Ting, and 劉彥廷. "Hydraulic Analysis of Rectangular Lateral Weir." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/a55mxs.
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Hoque, Md Azizul. "Hydraulic analysis of ice-covered river flow." Thesis, 2009. http://spectrum.library.concordia.ca/976601/1/MR63326.pdf.
Full textAbstract:
For a substantial portion of the year many Canadian rivers are frozen. River ice is known to have an important impact on the water cycle and hydraulic engineering infrastructures. From the hydraulics perspective, the formation of an ice cover on the river surface causes an increase in resistance to flow and therefore a decrease in discharge to downstream. In the subject area of ice covered river hydraulics, there have been limited studies. In this study we have quantified the differences in flow velocity, discharge and flow energy distributions between conditions with and without the ice cover. We have also estimated the roughness of the ice cover underside using the boundary layer theory. Based on our flow analysis of a larger number of ice-covered rivers in Canada, the boundary layer profiles beneath the ice cover and above the channel bed are rarely symmetric, i.e. the dynamic effect of the ice cover and that of the channel bed differ. Many of the observed velocity profiles are too complicated to be described using simple analytical functions. The presence of the ice cover can reduce the hydraulic radius of a cross section by as much as 46% and flow discharge by 60%, in comparisons to the corresponding values associated with open channel conditions. Under ice covered conditions the flow is very sensitive to the friction parameter. For a given river cross section, the difference in flow velocities with and without an ice cover is between 39% and 60%
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Lai, Wei-Yu, and 賴威宇. "Analysis of In-situ Hydraulic Conductivity Tests." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/psmhzz.
Full textAbstract:
碩士國立交通大學
土木工程系所
92
In-situ hydraulic conductivity tests have been widely used in field investigations for construction project nowadays. In this study, in order to estimate the cause of various outcomes, in-situ hydraulic testes such as Double-Ring Infiltrometer, Two-Stage Borehole Permeameter, Guelph Permeameter, and Simplified Borehole Test were conducted to compare their applicability in silty and clayey soils. In addition, numerical analysis was performed with a finite-element program, FEMWATER, to further analyze the results of the in-situ tests. The tests were simulated with FEMWATER by using the hydraulic conductivity and soil water characteristic curves obtained from laboratory experiment. The effect of anisotropy of hydraulic conductivity was also studied. Due to the difficulty of quantifying the influence of macropores and fissures in the soils on the hydraulic conductivity, the soils were assumed to be homogeneous. The study showed that the in-situ hydraulic conductivity obtained by the Guelph Permeameter was the lowest and the closest to that from the laboratory tests. On the other hand, the hydraulic conductivity measured by the Double-Ring Infiltrometer tests and Simplified Borehole tests difference were much greater. However, considering the effect of anisotropy and macropores of soil, Double-Ring Infiltrometer test could give more reliable results than Guelph Permeameter and Simplified Borehole Test.
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洪振育. "Lungmen ABWR Containment Thermal Hydraulic information analysis." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/77433915401185327739.
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Lin, Yu-kai, and 林義凱. "Formability analysis of tube hydraulic bulge forming." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/47213857269783692369.
Full textAbstract:
博士國立中山大學
機械與機電工程學系研究所
93
Tube hydroforming process is a relatively new technology compared to conventional manufacturing via stamping and welding. However there is not much knowledge available for the product or process designers. The objective of this study will determine the flow stress and forming limit diagram of tubular materials to discuss the formability of tubes. Firstly, a mathematical model is proposed to examine the plastic deformation behavior of a thin-walled tube at different process parameters during the bulge hydroforming process without axial feeding. In the formulation of this mathematical model, an ellipsoidal surface and non-uniform thinning in the free bulged region and sticking friction between the tube and die are assumed. In the sticking friction mode, the elements after contact with the die do not move or slide. The effects of various forming parameters, such as the die entry radius, the bulge length, anisotropy, the initial thickness of the tube, etc., upon the forming pressures are discussed systematically. Secondly, an analytical model combined with hydraulic bulge tests is proposed to evaluate the properties of tubular materials considering anisotropy effect. Annealed AA6011 aluminum tubes and SUS409 stainless steel tubes are used for the bulge test. The tube thickness and radius at the pole and the internal forming pressure are measured simultaneously during the bulge test. The anisotropic values are obtained from tensile tests. From above experimental data, the effective stress - effective strain relations can be derived by this analytical model. The finite element method is used to conduct the simulations of hydraulic bulge forming with the flow stresses obtained by the above-mentioned model. The analytical forming pressures versus bulge heights are compared with the experimental results to validate the approach proposed in this study. Finally, this study also establishes the Forming Limit Diagram (FLD) of aluminum tubular material. An experimental system of tube hydroforming in which axial feed is applied to carry out the hydraulic bulge-forming test of the annealed aluminum alloy tubes. Furthermore, Hill’s new yield criterion is also used to predict the Forming Limit Curves of sheets. The predicted forming limit diagrams are compared with the experimental data. The results of this study can provide useful knowledge for process design. In addition, the process parameters of flow stress and forming limit diagram obtained can improve the accuracy of the simulation results in industrial and academic fields.
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Huang, Jian-Cheng, and 黃建成. "Analysis of Hydraulic Bulge Forming of Tubes." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/44754437802254565013.
Full textAbstract:
碩士國立中山大學
機械工程學系研究所
89
A mathematical model considering ellipsoidal surface for the forming tube is proposed in this work to examine the plastic deformation behavior of a thin-walled tube during tube bulge hydroforming process in an open die. In the formulation of this mathematical model, nonuniform thinning in the free bulged region and sticking and sliding friction modes between the tube and die are considered. In the sticking friction mode, the elements in contact with the die do not move or slide after contact with the die. Whereas, in the sliding friction mode, the elements in contact with the die will continue to deform plastically in the subsequent forming process. The relationship between the internal pressure and the bulge height of the tube is examined. The effects of various forming parameters such as the die entry radius, the initial thickness, the length/diameter ratio, material property, etc., upon the forming pressure and the thickness distribution of products were discussed systematically.
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Shiu, Yu-Sheng, and 許煜聖. "Hydraulic Analysis of Flow Passing Vegetative Ground." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/09378228980119998147.
Full textAbstract:
碩士國立中興大學
水土保持學系
91
In this study, we aim to figure out how vegetation influences streamwise velocity by analyzing the velocity of flow passing vegetative ground and dividing the flow field into three regions: homogenous water-layer (the flow over vegetation), vegetation-layer (the flow inside vegetation) and permeable soil-layer (the flow inside the soil). The soil and vegetation are both regarded as porous media and the flow inside the two layers is porous media flow. Thus the nonzero velocity at the ground surface could be estimated. The velocity distribution of the submerged vegetation is solved first, and then degenerate the former solution into unsubmerged vegetation and no vegetative ground. The velocity in laminar flow is solved by simplified Navier-Stokes equations and Song’s (1993) laminar model based on Biot’s poroelastic theory. And in turbulent flow, the governing equation is modified from Navier-Stokes equations and Biot’s poroelastic theory. After solving velocity distribution under any possible situations, we compare the profiles of velocity with the experiment data of Rowiński and Kubrak (2002). As expected, we find it fit well and this reveals that the present solutions of velocity distribution can describe appropriately the flow passing vegetative ground in the turbulent flow.