The particle trap impactor

Abstract

The performance of virtual impactors with no flow through the impaction orifice was examined experimentally. An open cavity particle trap with an orifice diameter 1.9 times the jet diameter yielded sharp size cuts with a maximum collection efficiency of about 90 percent, with no degradation of performance at very high Stokes number. The suitability of the particle trap for operation with jet velocities up to the sonic limit and for use at elevated temperature was also demonstrated. In extended duration operation, the collection efficiency did not decrease until the trap was nearly filled. © 1988.