Measurements of non-equilibrium and equilibrium temperature behind a strong shock wave in simulated martian atmosphere

Non-equilibrium radiation measurements behind strong shock wave for simulated Martian atmosphere are presented in this paper. The shock wave is established in a hydrogen oxygen combustion driven shock tube. Timeresolved spectra of the Δv = 0 sequence of the B2Σ+ → X2Σ+ electronic transition of CN have been observed through optical emission spectroscopy (OES). A new method, which is based on fitting high resolution spectrum for rotational and vibrational temperatures measurement, is proposed to diagnose temperature distribution behind the shock wave. It is estimated that the current scheme has the maximum deviation less than 8% (1σ) for vibrational temperature measurement through detailed analysis of the influence of the uncertainties of spectroscopic constants and spectral resolution. Radiation structure of the shock layer, including induction, relaxation and equilibrium process, and corresponding rotational and vibrational temperatures are obtained through time gating OES diagnostics with sub-microsecond temporal resolution. The present extensive results will strongly benefit the reaction rate estimation and computational fluid dynamics (CFD) code validation in high enthalpy Mars reentry chemistry.

[1]  G. Herzberg,et al.  Molecular Spectra and Molecular Structure , 1992 .

[2]  P. Bernath,et al.  Fourier transform jet emission spectroscopy of the B2Σ+-X2Σ+ transition of CN , 1992 .

[3]  M. Slack.  Kinetics and thermodynamics of the CN molecule. III. Shock tube measurement of CN dissociation rates , 1976 .

[4]  Pascal Boubert,et al.  Nonequilibrium Radiation in Shocked Martian Mixtures , 2010 .

[5]  R. Manning,et al.  Mars exploration entry, descent and landing challenges , 2006, 2006 IEEE Aerospace Conference.

[6]  T. Mcintyre,et al.  Nonequilibrium Radiation Intensity Measurements in Simulated Titan Atmospheres , 2010 .

[7]  Kazuhisa Fujita,et al.  Rotational-Temperature Measurements of Chemically Reacting CN Using Band-Tail Spectra , 2009 .

[8]  Lazhar Houas,et al.  Shock-tube analysis of argon influence in Titan radiative environment , 1996 .

[9]  Deepak Bose,et al.  Modeling and experimental assessment of CN radiation behind a strong shock wave , 2006 .

[10]  Graham V. Candler,et al.  Chemical-kinetic problems of future NASA missions , 1991 .

[11]  C. Rond,et al.  Chemical Kinetic and Radiative Simulations for Titan Atmospheric Entry , 2009 .

[12]  Peter A. Jacobs,et al.  Nonequilibrium radiation intensity measurements in simulated titan atmospheres , 2008 .

[13]  Tahir Gokcen,et al.  N2-CH4-Ar Chemical Kinetic Model for Simulations of Atmospheric Entry to Titan , 2004 .

[14]  Ram,et al.  Fourier Transform Emission Spectroscopy of the , 1999, Journal of molecular spectroscopy.

[15]  P. Knowles,et al.  The A 2Π–X 2Σ+ red and B 2Σ+–X 2Σ+ violet systems of the CN radical: Accurate multireference configuration interaction calculations of the radiative transition probabilities , 1988 .

[16]  G. Herzberg,et al.  Molecular Spectra and Molecular Structure: I. Spectra of Diatomic Molecules , 1944 .

[17]  R. Engleman,et al.  Fourier transform emission spectroscopy of the B2Σ+–X2Σ+ system of CN , 2006 .

[18]  G. Herzberg.  Molecular Spectra and Molecular Structure IV. Constants of Diatomic Molecules , 1939 .

[19]  Anne Bourdon,et al.  Collisional-radiative model in air for earth re-entry problems , 2006 .

[20]  David W. Bogdanoff,et al.  Shock Radiation Measurements for Mars Aerocapture Radiative Heating Analysis , 2008 .

[21]  R. S. Ram,et al.  Fourier transform emission spectroscopy of ScN , 1992 .

[22]  D. Fletcher,et al.  Spectroscopic Analysis of Titan Atmospheric Plasmas , 2008 .

[23]  M. Wright,et al.  Shock Layer Radiation Measurements and Analysis for Mars Entry , 2009 .

[24]  A. Chikhaoui,et al.  Radiation Measurements in a Shock Tube for Titan Mixtures , 2007 .