Iain D. Boyd
Sibley School of Mechanical and Aerospace Engineering
Cornell University, Ithaca, NY
A new dissociation model for the direct simulation Monte Carlo
(DSMC) method is formulated using the threshold line concept.
This model considers in some detail the coupling between the
vibrational energy distribution of molecules in a gas and the rate of
dissociation. For a particular reaction, the new threshold line
model only requires determination of a leading multiplicative
constant and is therefore significantly less deterministic than
existing DSMC chemistry models. The new model is evaluated in
a heat bath under equilibrium and nonequilibrium conditions.
It is also employed to calculate hypersonic shock waves of nitrogen
and air. Comparison of the results generated with the new model
is made with existing experimental data and with previous computational
results. The more detailed DSMC implementation reveals properties of the
threshold line dissociation model not apparent in the previous
continuum implementation.