21 Sep 2023
 | 21 Sep 2023
Status: this preprint is currently under review for the journal AMT.

Performance characterization of a laminar gas-inlet

Da Yang, Margarita Reza, Roy Mauldin, Rainer Volkamer, and Suresh Dhaniyala

Abstract. Aircraft-based measurements enable large-scale characterization of gas-phase atmospheric composition, but these measurements are complicated by the challenges of sampling from high-speed flow. Under such sampling conditions, the sample flow will likely experience turbulence, accelerating | mixing of potential contamination of the gas-phase from the condensed-phase components on walls and reduced vapor transmission due to losses to the inner walls of the sampling line. 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 forward-facing laminar flow gas inlet to establish its performance 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 sample transport. The CFD results of flow features in the inlet are compared against measurements of air speed and turbulent intensity from full-sized high-speed wind-tunnel experiments. These comparisons suggest that the Reynolds Averaged Navier-Stokes (RANS) CFD simulations using the Shear Stress Transport (SST) modeling approach provide the most reasonable prediction of the turbulence characteristics of the inlet.

Da Yang et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on amt-2023-196', Anonymous Referee #1, 10 Oct 2023
    • CC1: 'Reply on RC1', Suresh Dhaniyala, 14 Oct 2023
  • RC2: 'Comment on amt-2023-196', Anonymous Referee #2, 08 Nov 2023

Da Yang et al.


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Short summary
This manuscript evaluated the performance of an aircraft gas inlet. Here, we used computational fluid dynamics (CFD) and experiments to demonstrate the role of turbulence in determining sampling performance of a gas inlet and identify ideal conditions for inlet operation to minimize gas loss. Experiments conducted in a high-speed wind-tunnel under near aircraft speeds validated numerical results. We believe that the results obtained from this work will greatly inform future gas inlet studies.