KINETIC THEORY OF THERMAL TRANSPIRATION,
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)
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 1967
- Accession Number
- AD0647843
Entities
People
- Yau Wu
Organizations
- University of Illinois Urbana–Champaign