
Accession Number : AD0659317
Title : HEAT CONDUCTION IN A RAREFIED GAS BETWEEN CONCENTRIC CYLINDERS.
Descriptive Note : Technical Rept.,
Corporate Author : CALIFORNIA UNIV BERKELEY DIV OF AERONAUTICAL SCIENCES
Personal Author(s) : Su,ChihLan
Report Date : AUG 1967
Pagination or Media Count : 93
Abstract : Heat conduction through a rarefied gas contained between concentric cylinders is studied analytically. Emphasis is placed on the connection with the experimental determination of thermal accommodation coefficients by the lowpressure method. The linearized BGKWmodel equation is used, and the linearization procedure based on small relative temperature difference is justified. Two coupled linear integral equations of the perturbed temperature and density are then formulated. A variational principle for the heat flux is found for arbitrary Knudsen number. An asymptotic analysis is carried out for the case of mean free path much greater than the inner but of the same order as the outer cylinder radius, which corresponds to typical operating conditions of the experiment mentioned above. The lowest order deviation of the heat flux from its freemolecular value is of O(ln(Kn)/Kn) and is the same as that obtained by the Knudsen iteration method. Numerical calculations are performed to find the next order correction term. It is found that for mean free path 20 or more times the inner cylinder radius the relative error introduced by using the freemolecular value for the heat flux is less than 5%, provided that the ratio of the mean free path over the outer cylinder radius is at least 0.2. (Author)
Descriptors : (*RAREFIED GAS DYNAMICS, *THERMAL CONDUCTIVITY), CYLINDRICAL BODIES, INTEGRAL EQUATIONS, TEMPERATURE, KNUDSEN NUMBER, NUMERICAL ANALYSIS
Subject Categories : Aerodynamics
Fluid Mechanics
Thermodynamics
Distribution Statement : APPROVED FOR PUBLIC RELEASE