The spinning rotor gauge: measurements of viscosity, velocity slip coefficients, and tangential momentum accommodation coefficients for N 2 and CH 4

Abstract

A selection of experimental measurements for N 2 and CH 4 made with a spinning rotor gauge (SRG) employing 4.00 mm and 4.50 mm diameter spherical steel rotors are reported. The experiments covered the continuum and slip regimes for both polyatomic gases. Theoretical results from a previous paper on the SRG are used to extract values of the viscosity, the velocity slip coefficient, and the tangential momentum accommodation coefficient from the experimentally obtained data for each of the gases. The measured viscosities are in excellent agreement with existing literature values. The question of whether there is an angular dependence (via the motor head alignment) in the measurements that was raised in our previous work [Tekasakul et al., JVSTA, 1996, 14, 2946] is addressed.