Third M.I.T. Conference on Computational Fluid and Solid Mechanics June 14–17, 2005  

Nonequilibrium relaxation in high-temperature gas flows

Eswar Josyulaa,*, Kun Xub
aAir Force Research Laboratory, Wright-Patterson Air Force Base, Ohio 45433, USA bHong Kong University of Science and Technology, Dept. of Mathematics, Hong Kong

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Numerical simulations are presented of steady-state, hypersonic flows for the prediction of multi-translational and rotational temperatures, and vibrational energy distributions, in order to understand the thermodynamic nonequilibrium phenomena encountered along the trajectory of the hypersonic fiowfields of aerospace vehicles. A new gas kinetic, multi-translational temperature model for a monoatomic gas was developed by solving equations derived from the Boltzmann equation with a first-order Chapman-Enskog expansion of an anisotropic velocity distribution function. The nonequilibrium vibrational energy distributions were modeled by the master equation and the population distributions in the quantum energy states of the di-atomic molecule evaluated under multiple-quantum vibrational-translational energy exchanges.

Keywords:  High-speed, high-temperature, gas flows; Nonequilibrium relaxation; Multi-translational temperature; Rotational and vibrational energy modes

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