Accession Number : AD0647843

Title :   KINETIC THEORY OF THERMAL TRANSPIRATION,

Corporate Author : ILLINOIS UNIV URBANA COORDINATED SCIENCE LAB

Personal Author(s) : Wu,Yau

Report Date : FEB 1967

Pagination or Media Count : 30

Abstract : The thermal transpiration law has been revised in a rigorous treatment. This phenomenon, discovered by Newmann, Feddersen and Reynolds, has been treated by Maxwell and Knudsen from kinetic theory considerations. In the present report, it was shown that the Maxwell and Knudsen theories do not give a detailed, microscopic description and are only valid for a system with near Maxwellian distribution everywhere. However, the revised and exact theory contains a set of new invariants which deviate from the classical theory by a geometrical factor I. This factor (isotropy) is a measure of the isotropic characteristics of the velocity distribution function in a stationary non-equilibrium system. The new invariants of thermal transpiration in the Knudsen regime are pI/square root of T and n(square root of T) I. In general, I is not equal to unity or a constant value in a thermal transpiration system. (Author)

Descriptors :   (*HEAT TRANSFER, *KINETIC THEORY), ISOTROPISM, VELOCITY, DISTRIBUTION FUNCTIONS, GASES, RAREFIED GAS DYNAMICS

Subject Categories : Physical Chemistry
      Thermodynamics

Distribution Statement : APPROVED FOR PUBLIC RELEASE