Abstract
Direct numerical simulations (DNS) of a turbulent premixed flame in an auto-ignitive dimethyl-ether (DME)/air mixture exhibiting two-staged ignition were conducted at elevated pressure and temperature using a statistically stationary planar configuration. Three sets of conditions with an identical turbulence intensity, but different stratification/turbulence length scales and correlations between temperature (T) and equivalence ratio (f) fields were simulated to study the dynamics of turbulent premixed flame propagation at auto-ignitive conditions. The influence of different stratification length scales and T-f correlations on turbulent flame speed was examined by comparing the flame statistics obtained from 2D simulations against laminar 1D solution. A global analysis of the front propagation speed was carried out for determining the effect of turbulent wrinkling and the role of upstream auto-ignition on the overall burning rate.
