Effect of Heavy-Particle Impact Excitation Processes on Post Shock Nonequilibrium Air radiation

A Lemal; Carolyn Jacobs; M Y Perrin; C O Laux; P Tran; E Raynaud

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Effect of Heavy-Particle Impact Excitation Processes on Post Shock Nonequilibrium Air radiation

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Effect of Heavy-Particle Impact Excitation Processes on Post Shock Nonequilibrium Air radiation

A Lemal, Carolyn Jacobs, M Y Perrin, C O Laux, P Tran and E Raynaud

Proceedings of the 8th European Symposium on Aerothermodynamics for Space Vehicles, pp.1-10

European Symposium on Aerothermodynamics for Space Vehicles, 8th (Lisbon, Portugal, 02-Mar-2015–06-Mar-2015)

European Space Agency

2015

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Abstract

Aerospace Engineering

heavy-particle impact

collisional-radiative (CR) model

Ecole Centrale Paris

vacuum ultra violet (VUV)

infrared (IR) spectral ranges

spectral ranges

The absolute radiation measurements obtained in the Electric-Arc driven Shock-Tube (EAST) facility at NASA Ames Research Center were analyzed to test the collisional-radiative (CR) model developed at Ecole Centrale Paris. Two conditions representative of Earth reentry at 10.54 and 11.17 km/s were investigated in the vacuum ultra violet (VUV) and infrared (IR) spectral ranges. For each of the conditions, the corresponding CCD images were analyzed. The electron number density was inferred from Starkbroadened nitrogen and Hα lines. Comparisons with the predicted electron number density profiles enabled us to validate the ionization rate constant model implemented in the flowfield. For both freestream conditions and all the spectral ranges, the predictions of the initial intensity rises are improved when the total spatial smearing (due to the shock motion, the optics and the camera) is taken into account. The nonequilibrium intensities observed in the VUV and IR spectral ranges were underpredicted by the CR model when only electron-impact excitation and ionization processes were taken into account. Then, the effect of heavy-particle impact processes was studied by applying various heavy-particle impact excitation models. The nonequilibrium peak intensities observed in the VUV and IR spectral ranges were shown to be controlled by heavy-particle impact excitation processes.

Details

Title: Effect of Heavy-Particle Impact Excitation Processes on Post Shock Nonequilibrium Air radiation
Authors: A Lemal (Author) - Laboratoire d'Energétique Moléculaire et Macroscopique, France
Carolyn Jacobs (Author) - SUPELEC, France
M Y Perrin (Author) - Laboratoire d'Energétique Moléculaire et Macroscopique, France
C O Laux (Author) - Laboratoire d'Energétique Moléculaire et Macroscopique, France
P Tran (Author) - Airbus Group, France
E Raynaud (Author) - Airbus Group, France
Publication details: Proceedings of the 8th European Symposium on Aerothermodynamics for Space Vehicles, pp.1-10
Conference details: European Symposium on Aerothermodynamics for Space Vehicles, 8th (Lisbon, Portugal, 02-Mar-2015–06-Mar-2015)
Publisher: European Space Agency
Date published: 2015
Organisation Unit: School of Science and Engineering - Legacy; University of the Sunshine Coast, Queensland
Language: English
Record Identifier: 99451172802621
Output Type: Conference paper

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