The Experts below are selected from a list of 104949 Experts worldwide ranked by ideXlab platform
S Fujii - One of the best experts on this subject based on the ideXlab platform.
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Performance analysis of scramjet engine with quasi-One-Dimensional Flow model
International Journal of Hydrogen Energy, 1991Co-Authors: Y Tsujikawa, Y Tsukamoto, S FujiiAbstract:Abstract In the present study, the quasi-One-Dimensional Flow model through the scramjet engine which consists of the inlet, combustor and nozzle is proposed. The performances of the compOnents are analysed thermodynamically. In the analysis, there are severe difficulties in the combustor due to problems such as turbulent diffusion of hydrogen fuel and mixing with air at supersonic speed range. For the combustion reaction, the global hydrogen-air combustion model with two-step reaction schemes of hydrogen and oxygen are introduced. To estimate the demerit of weight increase, the axial length of the compOnents is calculated, which presented the basic information about the optimum configuration of the scramjet engine.
Irene Borde - One of the best experts on this subject based on the ideXlab platform.
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Steady state One Dimensional Flow model for a pneumatic dryer
Chemical Engineering and Processing: Process Intensification, 1999Co-Authors: Avi Levy, Irene BordeAbstract:Abstract A One-Dimensional steady-state mathematical model for dilute phase Flow in a pneumatic dryer is presented. The model takes into account mass, momentum and heat transfer between the gas and the particle phases. The model was applied to the drying process of wet PVC particles in a large-scale pneumatic dryer. The rate of drying was controlled by a two-stage drying process. In the first drying stage, heat transfer controls evaporation from the saturated outer surface of the particle to the surrounding gas. At the second stage, the particles were assumed to have a wet core and a dry outer crust; the evaporation process of the liquid from a particle is assumed to be governed by diffusion through the particle crust and by convection into the gas medium. As evaporation proceeds, the wet core shrinks while the particle dries. The drying process is assumed to stop when: the moisture content of a particle falls to a predefined value; or when the particle riches the exit of the pneumatic dryer. The One-Dimensional pneumatic drying model was solved numerically and two operating conditions, adiabatic and given pneumatic dryer wall temperature, were simulated. The prediction of the numerical simulation was compared successfully with experimental results of drying of wet PVC particles conveyed with air in a large-scale pneumatic dryer.
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Mathematical Modeling of Drying of Liquid/Solid Slurries in Steady State One-Dimensional Flow
Drying Technology, 1995Co-Authors: D. Levi-hevroni, Avi Levy, Irene BordeAbstract:ABSTRACT A mathematical model of simultaneous mass, heat and momentum transfer for two-phase Flow of a gas and a solid/liquid slurry was developed. The model was applied to calculation of the drying process of coal-water slurry droplets in a gas medium in a steady One-Dimensional Flow. The model was based on the well-known two-stage drying process for slurry droplets. After the first period of drying, in which the evaporation rate is controlled by the gas phase resistance, the evaporating liquid diffuses through the porous shell (crust) and then, by convection, into the gas medium. Inside the dry external crust of the drop, a wet central core forms, which shrinks as evaporation proceeds. The temperature of the slurry droplet rises. The process ends when the temperature of the dry outer crust reaches the coal ignition temperature in the case of combustion or when the moisture of the particle reaches the final required moisture. The developed model was based on One-Dimensional balance equations of mass, ene...
J. H. Horlock - One of the best experts on this subject based on the ideXlab platform.
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On One-Dimensional Flow of a conducting gas between electrodes – with application to MHD thrusters
Journal of Fluid Mechanics, 1994Co-Authors: M. D. Cowley, J. H. HorlockAbstract:Inviscid, adiabatic, One-Dimensional Flow of a conducting gas in the presence of crossed electric and magnetic fields is investigated for the case where the magnetic field is generated by the current being supplied to the gas. The electrode geometry and the connections to the electrical power supply are such that the magnetic field falls to zero at the downstream end of the MHD duct. The analysis allows for magnetic Reynolds number r, to be anywhere in the range 0 to 00. The main part of the investigation is restricted to consideration of ducts with constant spacing between electrodes. The way in which the density of the gas varies along the duct with the changing magnetic field is analysed generally and the results are then applied to the case where gas is fed to the MHD duct from high pressure in a plenum chamber and where the duct exhausts to a region of negligible pressure. If the Flow is choked by the converging entry to the duct and the magnetic Reynolds number is moderate to high, the main electromagnetic effect is for thej x B forces to accelerate the gas to supersonic speeds. As r, is reduced, ohmic heating becomes more important, and it may cause the Flow to be choked at exit from the duct, giving rise to a reduction in mass Flow. For certain ranges of Y, and ratio of initial magnetic pressure to plenum-chamber pressure the Flow may choke at a sonic point within the duct itself, while accelerating from subsonic to supersonic through the point. Some illustrative examples of how properties vary with distance along the duct have been computed and the consequences of the analysis for MHD thrusters are explored. The magnetic forces will augment thrust per unit cross-sectional area, the essential measure of this being the drop in magnetic pressure along the duct, but there is an upper limit on the ratio of magnetic pressure to plenum-chamber pressure for Flows to be possible. Flow at low magnetic Reynolds number is favoured if the object is to increase specific thrust by reducing mass Flow through the duct.
Dobroslav Znidarčić - One of the best experts on this subject based on the ideXlab platform.
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One-Dimensional Flow INFILTRATION THROUGH A COMPACTED FINE GRAINED SOIL
Soils and Foundations, 2011Co-Authors: Kátia Vanessa Bicalho, Dobroslav ZnidarčićAbstract:Compacted soils are widely used in engineering work and engineers often specify that cohesive soils be compacted either around or on the wet side of optimum water content. In general, at the corresponding degree of saturation values, water compOnent in soil voids is continuous but the air phase is not. The modelling of the infiltration process through compacted soils requires that unsaturated hydraulic functions be defined. A theoretical soil water retention function for soils with a discontinuous air phase is derived using the theory proposed by Schuurman (1966). Data from the test results provide encouraging evidence of the validity of the proposed theory. An empirical hydraulic conductivity function where the air is present in the form of occluded bubbles is also determined by curve fitting to the experimental measurements. A numerical solution of Richards' equation for One-Dimensional Flow, which incorporates the experimental findings, was used to simulate the measured transient water Flow. The results show that the proposed constitutive relationships are capable of producing simulations of the measurements of the unsaturated Flow that are both qualitatively and quantitatively realistic.
Y Tsujikawa - One of the best experts on this subject based on the ideXlab platform.
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Performance analysis of scramjet engine with quasi-One-Dimensional Flow model
International Journal of Hydrogen Energy, 1991Co-Authors: Y Tsujikawa, Y Tsukamoto, S FujiiAbstract:Abstract In the present study, the quasi-One-Dimensional Flow model through the scramjet engine which consists of the inlet, combustor and nozzle is proposed. The performances of the compOnents are analysed thermodynamically. In the analysis, there are severe difficulties in the combustor due to problems such as turbulent diffusion of hydrogen fuel and mixing with air at supersonic speed range. For the combustion reaction, the global hydrogen-air combustion model with two-step reaction schemes of hydrogen and oxygen are introduced. To estimate the demerit of weight increase, the axial length of the compOnents is calculated, which presented the basic information about the optimum configuration of the scramjet engine.
