Gas-surface accommodation coefficients from viscous slip and temperature jump coefficients

Analytical equations for the viscous slip and temperature jump coefficients for a gas flowing over a surface, obtained from a variational approach, are evaluated and compared with highly accurate numerical results for rigid sphere gas interactions. The gas-surface interaction is assumed to be governed by either the elastic-diffuse (Maxwell) one-parameter model or the Cercignani-Lampis two-parameter model. Approximate analytical equations obtained for solving the inverse problem to estimate the accommodation coefficient for the one-parameter model or the tangential momentum accommodation coefficient for the two-parameter model from an error-free measurement of the viscous slip coefficient are almost always accurate to within 3%. The corresponding estimate of the accommodation coefficient for the one-parameter model from the temperature jump coefficient is almost always accurate to within 5%. (c) 2005 American Institute of Physics.