This is a project to design, fabricate and test two new-concept aerosol inlets for use on aircraft, as part of a state-of-the-art, aircraft based aerosol sampling system. The major difference between these new inlets and commonly-used conventional isokinetic inlets is the development and use of active wall filtration. The "active" walls of the inlets are completely covered with a shaped filter substrate, and particles which hit these covered walls should be easily and efficiently captured. Turbulent deposition in the nozzle resulting from non-laminar flow, high airstream velocities and misalignment with the flow streamlines is not considered a major problem with these inlets. In fact, wall filtration may prove to be the preferred method of aerosol capture. A series of wind tunnel and aircraft experiments are proposed to answer this and other questions. Thus, aerosol "wall losses" which plagued earlier sampling efforts may become a thing of the past. These inlets are a major portion of a new aircraft sampling system we are in the process of developing. Funding is requested from NSF only for the design, building and testing of the inlets; other funding has been sought and acquired for the development of the remaining portions of the aircraft sampling system.
