Koh, J. C. Y.Overview
Most widely held works by
J. C. Y Koh
On a heat and mass transfer problem with two moving boundaries
by J. C. Y Koh
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Book
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2 editions published in 1968 in English and held by 4 WorldCat member libraries worldwide The heat and mass transfer problem in a passive transpiration cooling system involving two moving boundaries is formulated. A numerical calculation scheme and computer program are developed to solve the problem. Computations are performed for the case of porous tungsten infiltrated with copper exposed to an environment of high pressure and high heat flux. The effects of porosities and the radius of curvature on the thermal response and infiltrant recession are shown. (Author)
Pressure distribution and heat transfer for flow over simulated cylindrical parachutes
by J. C. Y Koh
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Book
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1 edition published in 1964 in English and held by 2 WorldCat member libraries worldwide
Nonsimilar boundary layer heat transfer of a rotating cone in forced flow
by J. C. Y Koh
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Book
)
2 editions published in 1965 in English and held by 2 WorldCat member libraries worldwide The problem of fluid flow and heat transfer characteristics of a cone rotating in a forced flow field is investigated. The flow problem in general involves two parameters, m and s. For heat transfer, one additional parameter, Pr, must be considered. For the special case of a rotating disk in forced flow, the partial differential equations are reduced to a set of ordinary differential equations with two parameters s and Pr. The nonsimilar boundary layer flow equations are solved for two half cone angles (alpha = 90 degrees and 53.5 degrees) for various Prandtl numbers with s ranging from 0 to about 20. It was found that for s = 10, the first order approximation from the power expansion scheme may not be sufficient. (Author)
Investigation of fluid flow and heat transfer in porous matrices for transpiration cooling
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Book
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1 edition published in 1966 in English and held by 1 WorldCat member library worldwide An investigation was conducted to determine the heat transfer and fluid flow characteristics in porous matrices for transpiration cooling. Governing differential equations were derived and solved using realistic boundary conditions. Parameters governing the resulting temperature and pressure distributions in porous matrices were identified. Geometry, transient, and dissociation effects on temperature and pressure distributions were determined. Fluid flow and heat transfer characteristics in twophase flows and multilayer matrices were also analyzed. Experimentally, 301 test runs were performed to measure the temperature distribution and pressure drops across the porous matrices using air, nitrogen, helium, and water as collants. Satisfactory agreement between calculated and measured temperature profiles was obtained. Information on permeability of porous matrices was derived. Good correlation was accomplished for viscous permeability as a function of porosity. (Author)
Fluid flow and heat transfer in hightemperature porous matrices for transpiration cooling
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Book
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1 edition published in 1966 in English and held by 1 WorldCat member library worldwide A detailed study of fluid flow and heat transfer characteristics in porous matrices has been performed. Refined prediction methods for pressure and temperature distribution in porous matrices have been developed to include the effects of gas conduction, internal heat sources, chemical reaction, nonsteady state flows and slip flow. The show system feasibility, a hightemperature multilayer matrix system has been developed. Six specimens, one inch in diameter, were fabricated and tested in an oxyacetylene flame with and without transpiration cooling. Some tests were performed under a cold wall heat flux of 235 Btu/ft sqsec. It was found that the specimens can withstand a surface temperature of over 3600 F for a period of 30 minutes. Thus, it has been demonstrated that a transpiration cooled thermal protection system may be developed for space vehicle applications. (Author)
Thermal Conductivity and Electrical Resistivity of Porous Material,
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Book
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1 edition published in 1971 in English and held by 1 WorldCat member library worldwide
Laminar free convection from a nonisothermal horizontal cylinder
by J. C. Y Koh
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Book
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1 edition published in 1963 in English and held by 1 WorldCat member library worldwide
Fundamental study of transpiration cooling : final report
by J. C. Y Koh
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Book
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1 edition published in 1973 in English and held by 1 WorldCat member library worldwide
Laminar free convection from a horizontal cylinder with prescribed surface heat flux
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Book
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1 edition published in 1963 in English and held by 1 WorldCat member library worldwide Laminar free convection from a horizontal cylinder having a prescribed surface heat flux is analysed. The wall surface heat flux is assumed to be varied in the manner of a sub 1 (X/R) square + a sub 2 (X/R) square. Special transformations are devised and employed so that the resulting differential equations and boundary conditions are free of the parameters a sub 1 and a sub 2. These differential equations are solved once and for all; solutions to the original equations for any particular values of a sub 1 and a sub 2 may then be obtained easily as linear combinations of the numerical solutions. It is found that the average Nusselt number for a cylinder having a uniform surface heat flux is larger than that for a cylinder having an isothermal surface by no more than 4 per cent. (Author) Audience Level
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