Numerical and experimental investigations of channel flows in a disk-type drag pump

Abstract

Pumping performance of a disk-type drag pump is studied numerically and experimentally. Molecular transition and slip flows that arise in a spiral channel on the rotating disk are simulated by using particle and continuum methods. The particle approach employs the direct simulation Monte Carlo (DSMC) method, and the continuum approach solves the Navier-Stokes (N-S) equations. A new DSMC code that can handle noninertial effects existing in the rotating frame of reference is developed. In this DSMC code, particular attention is paid to matching the solutions obtained by the N-S method in the slip flow regime. In the experimental study, the inlet pressures are measured for various outlet pressures of a test pump. Comparison between the experimental data and the numerical results reveals that the DSMC method provides the more accurate solution of the rarefied channel flow for the range of Knudsen number Kn>0.02 than does the N-S method.