Measurement of Gas-Surface Accommodation

Thermal accommodation coefficients have been determined for a variety of gas‐surface combinations using an experimental apparatus developed to measure both the pressure dependence of the conductive heat flux and the variation of gas density between parallel plates separated by a gas‐filled gap. Effects of gas composition, surface roughness and surface contamination have been examined with this system, and the behavior of gas mixtures has also been explored. Results are discussed in comparison with previous parallel‐plate experimental studies as well as numerical simulations.