Theoretical and experimental study of particle collection characteristics of high-velocity multijet cascade impactors

The absolute gas pressure at the impaction plate varies depending on the relative position of the jet orifice and the pressure tap. For subsonic flows, the pressure at the collection plate below the jet is quite near the upstream stagnation pressure.Owing to the variation of fluid properties in the impaction region below the compressible jet flow, the exact determination of the cut-off diameters requires careful calibration with monodisperse aerosols.