Numerical simulation of radiation measurements taken in the X2 facility for Mars and Titan gas mixtures

Palmer, Grant, Prabhu, Dinesh, Brandis, Aaron and McIntyre, Timothy J. (2011). Numerical simulation of radiation measurements taken in the X2 facility for Mars and Titan gas mixtures. In: 42nd AIAA thermophysics conference 2011. 42nd AIAA Thermophysics Conference 2011, Honolulu, HI, (). 27 - 30 June 2011.

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Author Palmer, Grant
Prabhu, Dinesh
Brandis, Aaron
McIntyre, Timothy J.
Title of paper Numerical simulation of radiation measurements taken in the X2 facility for Mars and Titan gas mixtures
Conference name 42nd AIAA Thermophysics Conference 2011
Conference location Honolulu, HI
Conference dates 27 - 30 June 2011
Proceedings title 42nd AIAA thermophysics conference 2011
Journal name 42nd AIAA Thermophysics Conference
Place of Publication Red Hook, NY United States
Publisher Curran Associates Inc
Publication Year 2011
Sub-type Fully published paper
Open Access Status
ISBN 9781624101465
Total pages 12
Abstract/Summary Thermochemical relaxation behind a normal shock in Mars and Titan gas mixtures is simulated using a CFD solver, DPLR, for a hemisphere of 1 m radius; the thermochemical relaxation along the stagnation streamline is considered equivalent to the flow behind a normal shock. Flow simulations are performed for a Titan gas mixture (98% N2, 2% CH4 by volume) for shock speeds of 5.7 and 7.6 km/s and pressures ranging from 20 to 1000 Pa, and a Mars gas mixture (96% CO2, and 4% N2 by volume) for a shock speed of 8.6 km/s and freestream pressure of 13 Pa. For each case, the temperatures and number densities of chemical species obtained from the CFD flow predictions are used as an input to a line-by-line radiation code, NEQAIR. The NEQAIR code is then used to compute the spatial distribution of volumetric radiance starting from the shock front to the point where thermochemical equilibrium is nominally established. Computations of volumetric spectral radiance assume Boltzmann distributions over radiatively linked electronic states of atoms and molecules. The CFD treats metastable states independently. The results of these simulations are compared against experimental data acquired in the X2 facility at the University of Queensland, Australia. The experimental measurements were taken over a spectral range of 310-450 nm where the dominant contributor to radiation is the CN violet band system. In almost all cases, the present approach of computing the spatial variation of post-shock volumetric radiance by applying NEQAIR along a stagnation line computed using a high-fidelity flow solver with good spatial resolution of the relaxation zone is shown to replicate trends in measured relaxation of radiance for both Mars and Titan gas mixtures.
Subjects 2202 History and Philosophy of Specific Fields
2210 Mechanical Engineering
3104 Condensed Matter Physics
Q-Index Code E1
Q-Index Status Provisional Code
Institutional Status UQ
Additional Notes AIAA 2011-3768

Document type: Conference Paper
Collection: School of Mathematics and Physics
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