DSMC Study of an H2/O2 Detonation Wave Structure

Abstract

Direct simulation Monte Carlo (DSMC) method was applied to numerical study of detonation in an H2/O 2 mixture with detailed chemical kinetics on the basis of effective DSMC molecular chemistry models. The results of the DSMC modeling of an unsteady detonation wave initiated by breakdown of a diaphragm between two channels with different pressures yield the velocity of detonation, which coincides with the ChapmanJouguet velocity. The internal structure of the detonation wave obtained in DSMC simulations is in good qualitative agreement with the detonation-wave structure calculated on the basis of the Zeldovich – von Neumann – Doering (ZND) theory. I. Introduction OLECULAR-LEVEL investigations of gas detonation are important both for applications associated with propagation of detonation waves at small scales and for basic research. The molecular-kinetic description of the gas at the level of the distribution functions of molecular velocities and internal states is usually used for rather rarefied gas flows, in particular, in problems of high-altitude aerothermodynamics of space vehicles [1], though it is also applicable for dense flows. The distribution function is sought as the solution of the integrodifferential Boltzmann kinetic equation, which describes the function evolution due to molecular transfer and collisions. The most effective numerical method for solving the Boltzmann equation is currently the Direct Simulation Monte Carlo (DSMC) method [2]. The conventional treatment of the DSMC method is based on considering the gas flow as a set of 10 5 -10 7 particles (each of them represents a large number of gas molecules) and on the principle of