Molecular level simulations of hydrogen-air flame at high pressures.

In this paper, molecular level simulations of a one-dimensional (1-D) hydrogen-air flame are performed at pressures of 0.1 MPa and 1 MPa using the Direct Simulation Monte Carlo (DSMC) method. DSMC has been previously used to successfully simulate hydrogen flames using traditional Arrhenius based reaction rates and using a novel quantum-kinetic (QK) model. The latter only uses collision data for determining the reaction outcome and is used in this study. Fundamental studies of combustion at high pressure are challenging and in this paper, the ability of the DSMC method to simulate hydrogen flames at high pressure is demonstrated. Results from DSMC are evaluated using a skeletal 12-step as well as a more detailed 21-step reaction mechanism, and are compared with those from 1-D Direct Numerical Simulation (DNS), showing a reasonable agreement in flame speed, flame temperature and species mass fraction at lower pressure. At high pressure, a good agreement in temperature and species mass fraction is found between DSMC and DNS. However, the flame speed particularly from the 12-step skeletal mechanism is overestimated from DSMC compared to that from the experiments. DSMC shows strong promise to carry out molecular level simulations at higher pressures but require improvements in associated models for better results. [ABSTRACT FROM AUTHOR]