Abstract
An implementation of the Macheret-Fridman (MF) dissociation model for the direct simulation Monte Carlo (DSMC) method is developed in this work. The model maintains the fundamental physical assumptions of the MF model, i.e., that high-energy collisions resulting in dissociation can be described by classical mechanics and are close to the impulsive limit, but also eliminates additional approximations of the MF model by using Monte Carlo sampling. Recent quasiclassical trajectory (QCT) calculations of , , and NO dissociation reactions and experimental measurements are used to validate the model. In general, the reaction rate constants and average vibrational energy removed at thermal equilibrium and nonequilibrium conditions are in good agreement with the QCT and experimental values. The discrepancies in the absolute values of thermal equilibrium rate constants found in some cases are shown to be caused by the underprediction of collision rates with the variable hard sphere model rather than by the MF model itself. QCT-calibrated collision rates combined with the MF dissociation model for the colliding pair are shown to yield a very good agreement between the computed thermal equilibrium dissociation rates and the QCT results. The model is also evaluated by simulating shock tube experiments with oxygen. The present study suggests the possibility of using the model as the standard dissociation reaction model for nonequilibrium flows.
17 More- Received 5 June 2018
DOI:https://doi.org/10.1103/PhysRevFluids.3.113401
©2018 American Physical Society