The UNIC code [1, 2, 3] is adopted to study the flow field in turbo vacuum pumps in the slip and continuum flow regimes. The mathematical model is set on a rotating frame of reference. Discretization of equations is performed on body-fitted curvilinear mesh systems. A third-order upwind TVD (Total Variation Diminishing) scheme is used for approximating the convective terms of the transport equations while the viscous terms are approximated by the central difference. To deal with the coupling between pressure and velocity a pressure-based predictor/corrector solution procedure is employed. An implicit Euler time marching scheme is used to advance calculation until steady state is reached. Three types of turbo vacuum pumps, that is, radial type of Siegbahn molecular drag pump, the axial type of Holweck molecular drag pump, and a compound turbo booster pump combining the turbo blade pump and the Holweck pump are investigated in this work. The results show that the CFD methodology can be successfully applied to the simulation of the pumps. Detailed velocity and pressure fields obtained can help to improve design of new types of pump.
|Number of pages||7|
|Journal||Transactions of the Aeronautical and Astronautical Society of the Republic of China|
|State||Published - 1 Mar 2000|