Velocity Measurements in Channel Gas Flows in the Slip Regime by means of Molecular Tagging Velocimetry
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
- Univ. de Toulouse (France). Inst. Clement Ader (ICA), CNRS, INSA, ISAE-SUPAERO
Direct measurements of the slip velocity in rarefied gas flows produced by local thermodynamic non-equilibrium at the wall represent crucial information for the validation of existing theoretical and numerical models. In this work, molecular tagging velocimetry (MTV) by direct phosphorescence is applied to argon and helium flows at low pressures in a 1-mm deep channel. MTV has provided accurate measurements of the molecular displacement of the gas at average pressures of the order of 1 kPa. To the best of our knowledge, this work reports the very first flow visualizations of a gas in a confined domain and in the slip flow regime, with Knudsen numbers up to 0.014. MTV is cross-validated with mass flowrate measurements by the constant volume technique. The two diagnostic methods are applied simultaneously, and the measurements in terms of average velocity at the test section are in good agreement. Moreover, preliminary results of the slip velocity at the wall are computed from the MTV data by means of a reconstruction method
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- USDOE National Nuclear Security Administration (NNSA); European Community Seventh Framework Program
- Grant/Contract Number:
- 89233218CNA000001
- OSTI ID:
- 1648101
- Report Number(s):
- LA-UR--20-22677
- Journal Information:
- Micromachines, Journal Name: Micromachines Journal Issue: 4 Vol. 11; ISSN 2072-666X
- Publisher:
- MDPICopyright Statement
- Country of Publication:
- United States
- Language:
- English
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