Fabrication, Operation and Data Analysis of the University of Denver Low Turbulence Inlets on the NCAR C-130 for ACE-Asia

University Of Denver, Denver CO

Investigators

Abstract

Two low-turbulence inlets (LTIs) for use on the NCAR C-130 aircraft will be fabricated and deployed during the ACE-Asia program (Aerosol Characterization Experiment-Asia). These inlets permit the slowing of the aerosol sample from the true air speed of the airplane, approximately 100 m/s, to a few m/s without subjecting the sample to turbulent deposition in the diffuser. This turbulence reduction is achieved through boundary layer suction in the diffuser. A suction flow control system will be installed in order to maintain the desired sample flow as aircraft operating parameters change. The data characterizing the inlet performance will be collected and used to calculate the net enhancement factors which include the effects of anisokinetic sampling and inertial enhancement of large particles in the diffuser. These new inlets will, for the first time, allow airborne sampling of atmospheric aerosols of sub- and supermicron size without turbulent losses of larger particles. Even though large particles will actually be enhanced by these inlets, it will be possible to quantify their concentrations because the enhancement can be calculated. The inlets will be made available to NCAR/ATD and the community for use in future programs after the completion of ACE-Asia.