Analysis of the Heat Conductivity Data for Polar and Nonpolar Gases Using Thermal Transpiration Measurements

Abstract

Thermal transpiration experiments for carbon monoxide, nitric oxide, sulfur dioxide, and hydrogen sulfide at 366, 398, and 444°K are reported. The “dusty gas” model proposed by Mason, Evans, and Watson describes the variation of the thermomolecular pressure difference as a function of the mean pressure for each temperature. The thermal transpiration measurements for each gas were used to analyze the heat conductivity data for each gas. It appears that nonresonant rotational energy exchange must be included in the kinetic theory representation of the polar gas heat conductivities. The rotational collision numbers deduced from the thermal transpiration measurements are found to increase with increasing temperature. The recent model of the thermal transpiration effect developed by Loyalka reproduces these collision numbers and the temperature dependences.