The Direct Simulation of Detonations

Abstract

*† ‡ In this paper we review the status of the simulation of detonations using the direct simulation Monte Carlo method and report on progress in applications to the hydrogenchlorine system. Recent work with this stochastic approach has demonstrated successes in treating simple model systems, confirmed many of the details found in earlier analyses, and revealed new phenomena such as ultrafast detonations. Current efforts are directed toward simulations for fully realistic kinetic systems. These require a more elaborate and detailed treatment of dissociation and recombination reactions as well as energy exchanges involving many degrees of freedom and discrete vibrational levels. Initial results are encouraging and indicate such calculations are feasible for complex reaction systems. I. Introduction HE modern necessity for accurate computational methods for gas phase combustion modeling has made the treatment of kinetic systems an important challenge. Numerical methods spanning both continuum and particle based regimes have been used to model systems containing detonations. A detonation is a wave traveling at supersonic velocity in a gaseous medium, and it is driven by the energy released from the exothermic reactions within the wave. The continuum Navier-Stokes (NS) and Euler equations approximate the detonation front as a discontinuity of zero thickness, which may be acceptable if one is only concerned with the upstream or downstream conditions. The direct simulation Monte Carlo (DSMC) method is a stochastic method that can accurately calculate the upstream and downstream conditions of the system, as well as correctly simulate the details of the detonation wave structure given the appropriate level of grid resolution. The DSMC method has been used extensively to study the characteristics of one-dimensional detonations.