Performance Characterization of an Aircraft Inlet for Aerosol-Gas Sampling

DA YANG, Rainer Volkamer, Lee Mauldin, Margarita Reza, Suresh Dhaniyala, University of Colorado Boulder

     Abstract Number: 793
     Working Group: Instrumentation and Methods

Abstract
Aircraft-based measurements allow for large spatial-scale characterization of atmospheric aerosol and gas, but these measurements, under high-speed flow conditions, complicate efforts to maintain sample integrity through the inlet transport process. Of particular concern is the role of turbulence in driving loss of gas-phase species and aerosol particles. While a significant amount of research has gone into understanding aerosol sampling efficiency for aircraft inlets, a similar research investment has not been made for gas sampling. Here, we analyze the performance of a front-facing inlet as a function of operating conditions, including ambient pressure, freestream velocities, and sampling conditions. Using computational fluid dynamics (CFD) modeling, we simulate flow inside and outside the inlet to determine the extent of freestream turbulent interaction with the sample flow and its implication for gas and aerosol sample transport. The CFD results of flow features in the inlet are compared against high-speed wind-tunnel experiment results of average internal flow velocities, turbulence intensities, and gas transport losses. These comparisons provide critical validation of the reliability of turbulent models and support further validation of different designs. We will present the results of CFD simulations and wind-tunnel validation tests, and discuss implications for aircraft based gas-aerosol sampling.