Numerical simulations of flame acceleration and transition to detonation using the chemical-diffusive model

We describe the results of numerical simulations of flame acceleration and transition to detonation in a stoichiometric hydrogen-air mixture using different versions of the chemical-diffusive model (CDM). The CDM is an alternative approach to including the effects of chemical reactions and diffusive transport in compressible reactive Navier-Stokes solvers. CDM parameters are calibrated to reproduce selected combustion properties that are most important to flames and detonations. There are now two types of CDMs available for the simulations of the deflagration to detonation transition (DDT): one type is calibrated for the theoretical half-reaction distance of the Zel'dovich-Neumann-D\"oring detonation and the other is calibrated to reproduce the experimental detonation cell size. This presentation compares the results of simulations for stoichiometric hydrogen-air mixtures using these two CDMs for DDT in obstacle-laden channels with different geometrical configurations. The results are compared to experiments, and show that for channels whose widths are close to the critical size for onset of DDT, the CDM that reproduces the half-reaction distance tends to over-predict the likelihood of DDT. The CDM that reproduces the detonation cell size results in improved predictions.