O + HCI Cross Sections and Reaction Probabilities in DSMC

A chemical reaction model, suitable for use in the Direct Simulation Monte Carlo (DSMC) method, is developed to simulate hypervelocity collisions of an important reaction in atmospheric-jet interactions O(3P)+HCl(1Σ ) OH(2Π)+Cl(2P). The model utilizes the Quasi-Classical Trajectory (QCT) method with two potential energy surfaces (PES), new benchmark triple A and A surfaces and London-Eyring-Polanyi-Sato (LEPS) PES. The sensitivity of the flow to the fidelity of the chemical model is investigated for the new QCT-derived model and the widely used Total Collision Energy (TCE) model of Bird. The adequacy of the total collision cross section is also considered, and to obtain accurate collision cross sections, the Dynamic Molecular Collision model of Tokumasu and Matsumoto is assumed and the collision cross section is obtained by using the MD/QCT method with the aforementioned potential energy surfaces. The magnitude of the inelastic cross section is small compared to the total cross section for both PESs. Therefore, MD/QCT VHS-equivalent collision cross sections are obtained and along with the MD/QCT reaction cross sections are utilized in the full DSMC calculation of the flowfield. It is found that chemical reaction models do not affect the general flowfield, however, the OH production rate is dependent on the chemical reaction model.