1991 Volume 17 Issue 1 Pages 111-118
A finite difference scheme was proposed to determine the compressible fluid flow in the impactor. This scheme, based on the Lax & Wendroff and MacCormack ones, does not contain an explicit artificial dissipative term. The simulation results showed that the flow pattern and the separation efficiency of particles were determined by the ratio of downstream to upstream pressure. The effect of the jet-toplate distance and pressure ratio on the separation efficiency curves was studied. The Stokes number for the low-pressure impactor can be defined in terms of gas viscosity and mean free path at the nozzle as for the ordinary pressure impactor. The comparison between separation efficiency curves determined by simulation and measurements showed fairly good agreement at 50 % cut Stokes number.
