Abstract
Combustion properties of dimethyl ether (DME) and air mixtures have been elucidated in a spherical bomb by using schlieren images with high-speed camera, for equivalence ratios ranging from 0.8 to 2.0 at an initial pressure of 1 atm and a temperature of 298 K. The unstretched laminar burning velocities were deduced and compared with other study and calculation. Good and partial agreements were obtained with the other study and calculation, respectively. Flame response to stretch (represented by the Markstein number) were also considered both experimentally and computationally and were compared with methane, ethane, propane-air mixture. For our experimental conditions, stretched laminar burning velocities were found to vary linearly with flame stretch, yielding Markstein numbers for particular reactant conditions. In addition, turbulent burning velocities were measured for the above mixtures. In a given explosion, the burning velocity increased with time and radius, as a consequence of the continual broadening of the effective spectrum of turbulence and decreasing of the flame stretch to which the flame was subjected. A decrease in the Markstein number of the mixture increased the turbulent burning velocity.
