Heat transfer measurements of confined monatomic, diatomic, and triatomic gases in the transition region

Heat transfer measurements were experimentally performed on several rarefied gases at rest and confined between parallel plates. Helium, neon, argon, nitrogen, and carbon dioxide were tested. Measurements were made with copper plates and gold plated copper plates and three plate spacings, 0.036 cm, 0.0733 cm, and 0.139 cm. Data were taken from the free molecule region to the near continuum region with emphasis on the transition region under linearized conditions where the temperature difference between the plates was much less than the average temperature between the plates. Thermal accommodation coefficients measured in the free molecule region were used with the analytical results of Lees, Zeiring, and Gross-Zeiring for comparison with experimental data.