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Experimental And Numerical Investigations Of Two Phase Flow With Non Isothermal Boundary Conditions Under Microgravity Conditions
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Book Synopsis Experimental and Numerical Investigations of Two-Phase Flow with Non-Isothermal Boundary Conditions Under Microgravity Conditions by : Sebastian Schmitt
Download or read book Experimental and Numerical Investigations of Two-Phase Flow with Non-Isothermal Boundary Conditions Under Microgravity Conditions written by Sebastian Schmitt and published by . This book was released on 2017-04 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Experimental and Theoretical Investigations of the Physical Processes Related to the Retention Capability of a Double Screen Element against Liquid Hydrogen in Earth's Gravity and in Microgravity with Respect to the Applied Stimuli by : André Pingel
Download or read book Experimental and Theoretical Investigations of the Physical Processes Related to the Retention Capability of a Double Screen Element against Liquid Hydrogen in Earth's Gravity and in Microgravity with Respect to the Applied Stimuli written by André Pingel and published by Cuvillier Verlag. This book was released on 2022-08-04 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt: Metal screens are commonly used as components for fluid handling in spacecraft and rocket tank designs. In most cases, the screens perform a passive separation of the propellant phases. The separation of the liquid from the gaseous propellant phase, is a special challenge. Liquid-gas phase separation means that the gaseous phase is allowed to enter a phase separation device while the liquid phase is blocked. The technical application of this process is the depressurization in a propellant tank. A certain amount of the gaseous propellant phase is vented from the tank through the gas port. The liquid propellant phase remains in the tank in order to be stored for the engine. However, if the tank causes a liquid movement during the depressurization, a part of the liquid can potentially enter the gas port. In order to prevent the unwanted liquid outflow, a separation of the liquid from the gas is necessary. This is possible with the aid of a double screen element and has already been performed for storable liquids in Earth’s gravity and microgravity as well as for cryogenic liquids in Earth’s gravity. At the current state of the art, the separation of the liquid from the gaseous phase of the cryogenic propellant hydrogen using a double screen element has not been performed in microgravity. However, with regard to a possible application, it is mandatory to investigate the function of the double screen element for the real propellant under relevant environmental conditions. In this work, a cryogenic test facility has been developed and operated successfully under Earth’s gravity and microgravity conditions using the drop tower at the University of Bremen. Hereby, the original, cryogenic propellant phases: liquid and gaseous hydrogen, have been used. The experiments show the appearance of the physical processes which are related to the retention capability of a double screen element against liquid hydrogen. Furthermore, these physical processes can obviously be influenced by an unknown boundary condition at the screens: the screen saturation. This unknown boundary condition in turn can obviously be influenced by a certain stimulus which causes a special, fluid mechanical process. A simplified mathematical and two numerical models have been developed which combine the observed, physical processes in the experiments. Two fitting parameters are introduced which influence the flow through screen pressure loss of the liquid and the gaseous hydrogen phase. After the fitting to experimental data, the two fitting parameters have been interpreted with respect to a possible screen saturation. The results lead to a prediction of the unknown boundary condition and indicate that a partial saturation of the screens with liquid could be present in each considered experiment. This can possibly lead to a major influence of the overall resistance of the double screen element against liquid hydrogen.
Download or read book Applied mechanics reviews written by and published by . This book was released on 1948 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Scientific and Technical Aerospace Reports by :
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 1028 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Book Synopsis International Aerospace Abstracts by :
Download or read book International Aerospace Abstracts written by and published by . This book was released on 1999 with total page 974 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Bibliography of Lewis Research Center Technical Publications Announced in 1977 by : Lewis Research Center
Download or read book Bibliography of Lewis Research Center Technical Publications Announced in 1977 written by Lewis Research Center and published by . This book was released on 1978 with total page 356 pages. Available in PDF, EPUB and Kindle. Book excerpt: This compilation of abstracts describes and indexes over 780 technical reports resulting from the scientific and engineering work performed and managed by the Lewis Research Center in 1977. All the publications were announced in the 1977 issues of STAR (Scientific and Technical Aerospace Reports) and/or IAA (International Aerospace Abstracts). Documents cited include research reports, journal articles, conference presentations, patents and patent applications, and theses.
Download or read book NASA Technical Memorandum written by and published by . This book was released on 1994 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author :Volfango Bertola Publisher :CISM International Centre for Mechanical Sciences ISBN 13 : Total Pages :450 pages Book Rating :4.3/5 (91 download)
Book Synopsis Modelling and Experimentation in Two-Phase Flow by : Volfango Bertola
Download or read book Modelling and Experimentation in Two-Phase Flow written by Volfango Bertola and published by CISM International Centre for Mechanical Sciences. This book was released on 2003 with total page 450 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is an up-to-date review of recent advances in the study of two-phase flows, with focus on gas-liquid flows, liquid-liquid flows, and particle transport in turbulent flows. The book is divided into several chapters, which after introducing basic concepts lead the reader through a more complex treatment of the subjects. The reader will find an extensive review of both the older and the more recent literature, with abundance of formulas, correlations, graphs and tables. A comprehensive (though non exhaustive) list of bibliographic references is provided at the end of each chapter. The volume is especially indicated for researchers who would like to carry out experimental, theoretical or computational work on two-phase flows, as well as for professionals who wish to learn more about this topic.
Book Synopsis Behavior of Cryogenic Liquids Under Compensated Gravity and Non-isothermal Boundary Conditions by : Nikolai Kulev
Download or read book Behavior of Cryogenic Liquids Under Compensated Gravity and Non-isothermal Boundary Conditions written by Nikolai Kulev and published by . This book was released on 2020-02-04 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study deals with the investigation regarding the behavior of liquid cryogenic propellants in the launcher upper stages under microgravity with superheated tank walls. It contributes in this way to the application-oriented basic research by describing mathematically and quantifying experimentally the influence of evaporation on the interface reorientation of cryogenic liquids. In broader terms this work shows, both in a mathematical and an experimental way, the influence of the heat and mass transfer in the fluid and solid phases on the linear momentum transfer in the liquid phase due to the coupling of the transfer mechanisms. The main assumption behind this study is based on the principle that the solution of a partial differential equation depends on its boundary condition. In this case these are the mass balance boundary conditions at the interface and the contact line. These boundary conditions relate the respective liquid and the interface velocities to the mass flux due to interfacial evaporation, or phase change in general. A mathematical description of the reorientation was developed implementing an equation for the contact line boundary condition which takes explicitly into account the evaporation or the wall superheat at the contact line, respectively. Both the contact line velocity and the contact line angle become functions of the evaporation at the contact line and accordingly of the related dimensionless numbers. The implementation of the contact line boundary condition completes the equation system describing the non-isothermal flow macroscopically. A joint scaling approach of all field equations and boundary conditions was developed through which the influence of evaporation on the capillary-driven motion was expressed mathematically. This influence on the motion of the whole interface was experimentally quantified, too. For that purpose cryogenic liquids were used in drop tower experiments at ZARM, University of Bremen, with varying wall temper
Book Synopsis An Overview of Heat Transfer Phenomena by : Salim Newaz Kazi
Download or read book An Overview of Heat Transfer Phenomena written by Salim Newaz Kazi and published by IntechOpen. This book was released on 2012-10-31 with total page 540 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the wake of energy crisis due to rapid growth of industries, urbanization, transportation, and human habit, the efficient transfer of heat could play a vital role in energy saving. Industries, household requirements, offices, transportation are all dependent on heat exchanging equipment. Considering these, the present book has incorporated different sections related to general aspects of heat transfer phenomena, convective heat transfer mode, boiling and condensation, heat transfer to two phase flow and heat transfer augmentation by different means.
Book Synopsis Phase Separation in Two-phase Microfluidic Heat Exchangers by : Milnes P. David
Download or read book Phase Separation in Two-phase Microfluidic Heat Exchangers written by Milnes P. David and published by Stanford University. This book was released on 2011 with total page 151 pages. Available in PDF, EPUB and Kindle. Book excerpt: Two-phase microfluidic heat exchangers have the potential to meet the large heat dissipation demands of high power electronics and computing systems. Two-phase cooling systems face practical challenges brought on by the growth and advection of the vapor phase in the confined geometries, which lead to large pressure drops, increased thermal resistance and the formation of detrimental flow instabilities. One proposed solution to these issues is phase separation, whereby the vapor is locally separated from the two-phase flow through a porous hydrophobic membrane. This dissertation describes a series of studies conducted to develop an understanding of the factors that influence vapor separation and its impact on the hydraulic and thermal characteristics of two-phase heat exchangers. Flow phenomena are a critical component in developing this understanding of phase separation. High speed visualization of adiabatic and diabatic vaporizing flows was carried out in a single 124[Mu]m by 98[Mu]m copper microchannel with a 65[Mu]m thick, 220nm pore diameter hydrophobic PTFE membrane wall. During adiabatic air-water flow, wavy-stratified and stratified flow dominated lower liquid velocities, while plug and annular type flows dominated at the higher velocities. Analysis found that air removal could be improved by increasing the venting area, increasing the trans-membrane pressure or using thinner, high permeability membranes. Diabatic water-vapor experiments with mass flux velocities of 140 and 340 kg/s-m2 and exit qualities up to 20% found that stratified type flows dominate at lower mass fluxes while cyclical churn-annular flow became more prevalent at the higher mass-flux and quality. The observed flow regimes are hypothesized to play a significant role in determining the pressure drop and heat transfer coefficient during flow boiling. To study the impact of various geometric and membrane factors on the performance of a phase separating microchannel heat exchanger dissipating 100W of heat, a numerical model incorporating vapor separation and transport during two-phase flow boiling in a microchannel was developed. The impact of substrate thermal conductivity and thickness, membrane permeability and thickness, liquid channel density, liquid and vent channel diameter and vent-to-liquid channel diameter ratio was studied and compared for a standard non-venting heat exchanger, a vapor venting heat exchanger and a non-venting heat exchanger occupying the same increased volume as the venting heat exchanger. The numerical study found that the venting heat exchanger had improved pressure drop and device temperatures for all tested conditions when compared against a standard heat exchanger but only under very limited conditions when compared against the volumetrically equivalent non-venting heat exchanger. The study indicates that the best venting heat exchanger performance is achieved when the membrane conductance is of the same order or higher than that of the microchannel; this can be achieved through the use of thin high permeability membranes coupled with small hydraulic diameter microchannels. Finally, a study was conducted to explore the fabrication methods to build a vapor separating heat exchanger and to quantify the operating performance of multichannel silicon and copper phase separating devices. A copper parallel microchannel heat exchanger with nineteen 130[Mu]m square microchannels was built and tested at heat fluxes of up to 820 kW/m2 and water mass fluxes of between 102 and 420 kg/s-m2. Normalized pressure drop was improved by as much as 60% and average substrate temperature by a maximum of 4.4°C between the non-venting control and vapor venting device under similar operating conditions. Comparison between the experimental results and simulation predictions found higher than expected pressure drop improvements at higher mass fluxes and poorer heat transfer coefficients at the lowest mass flux. Based on the flow phenomena study these discrepancies are believed to be due to the mass flux and vapor quality dependent two-phase flow structures. The encouraging experimental and numerical results motivate further study into phase separation methods, materials and flow physics. The development of a high performance phase separating heat exchanger, with the thermal benefits of two-phase boiling flow and the hydraulic benefits of single-phase liquid flow, would strongly enable the adoption and application of two-phase heat exchangers to provide effective and efficient cooling for next generation high power computing systems.
Book Synopsis Two Phase Flow, Phase Change and Numerical Modeling by : Amimul Ahsan
Download or read book Two Phase Flow, Phase Change and Numerical Modeling written by Amimul Ahsan and published by BoD – Books on Demand. This book was released on 2011-09-26 with total page 600 pages. Available in PDF, EPUB and Kindle. Book excerpt: The heat transfer and analysis on laser beam, evaporator coils, shell-and-tube condenser, two phase flow, nanofluids, complex fluids, and on phase change are significant issues in a design of wide range of industrial processes and devices. This book includes 25 advanced and revised contributions, and it covers mainly (1) numerical modeling of heat transfer, (2) two phase flow, (3) nanofluids, and (4) phase change. The first section introduces numerical modeling of heat transfer on particles in binary gas-solid fluidization bed, solidification phenomena, thermal approaches to laser damage, and temperature and velocity distribution. The second section covers density wave instability phenomena, gas and spray-water quenching, spray cooling, wettability effect, liquid film thickness, and thermosyphon loop. The third section includes nanofluids for heat transfer, nanofluids in minichannels, potential and engineering strategies on nanofluids, and heat transfer at nanoscale. The forth section presents time-dependent melting and deformation processes of phase change material (PCM), thermal energy storage tanks using PCM, phase change in deep CO2 injector, and thermal storage device of solar hot water system. The advanced idea and information described here will be fruitful for the readers to find a sustainable solution in an industrialized society.
Download or read book Conference Papers Index written by and published by . This book was released on 1988 with total page 628 pages. Available in PDF, EPUB and Kindle. Book excerpt: Monthly. Papers presented at recent meeting held all over the world by scientific, technical, engineering and medical groups. Sources are meeting programs and abstract publications, as well as questionnaires. Arranged under 17 subject sections, 7 of direct interest to the life scientist. Full programs of meetings listed under sections. Entry gives citation number, paper title, name, mailing address, and any ordering number assigned. Quarterly and annual indexes to subjects, authors, and programs (not available in monthly issues).
Book Synopsis Fluid Mechanics Phenomena in Microgravity by : American Society of Mechanical Engineers. Winter Annual Meeting
Download or read book Fluid Mechanics Phenomena in Microgravity written by American Society of Mechanical Engineers. Winter Annual Meeting and published by . This book was released on 1992 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Two-Phase Gas-Liquid Flow in Pipes with Different Orientations by : Afshin J. Ghajar
Download or read book Two-Phase Gas-Liquid Flow in Pipes with Different Orientations written by Afshin J. Ghajar and published by Springer Nature. This book was released on 2020-03-14 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides design engineers using gas-liquid two-phase flow in different industrial applications the necessary fundamental understanding of the two-phase flow variables. Two-phase flow literature reports a plethora of correlations for determination of flow patterns, void fraction, two- phase pressure drop and non-boiling heat transfer correlations. However, the validity of a majority of these correlations is restricted over a narrow range of two -phase flow conditions. Consequently, it is quite a challenging task for the end user to select an appropriate correlation/model for the type of two-phase flow under consideration. Selection of a correct correlation also requires some fundamental understanding of the two-phase flow physics and the underlying principles/assumptions/limitations associated with these correlations. Thus, it is of significant interest for a design engineer to have knowledge of the flow patterns and their transitions and their influence on two-phase flow variables. To address some of these issues and facilitate selection of appropriate two-phase flow models, this volume presents a succinct review of the flow patterns, void fraction, pressure drop and non-boiling heat transfer phenomenon and recommend some of the well scrutinized modeling techniques.
Book Synopsis American Doctoral Dissertations by :
Download or read book American Doctoral Dissertations written by and published by . This book was released on 2001 with total page 776 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Physics Briefs written by and published by . This book was released on 1994 with total page 1256 pages. Available in PDF, EPUB and Kindle. Book excerpt:
