PAIR: Particulate Airborne Inlet Research

Summary

The PASIN program demonstrated that airborne aerosol inlets with sharp edges pass 50% or less of ambient particles to samplers inside an aircraft. On a recent King Air program in Monterey, CA, it was found that this largely-size-independent loss occurs just inside the tip of the inlet's diffuser-cone. The PAIR program examined the effects of two important parameters nozzle lip-shape and isoaxiality. Since curved leading edges reduce turbulence, it will be verified if they cause smaller losses than sharp edges do. By varying the alignment of nozzles with respect to the streamlines around the plane, the effect of reduced turbulent deposition in the inlets was measured.