Two stage reactions of dimethyl ether – Air mixture in micro flowreactor with controlled temperature profile

For examing the validity of reaction scheme that can produce two stage ignition behavior, ignition and combustion characteristics of premixed gaseous Dimethyl Ether (DME) - air mixture in a temperature profile controlled micro flowreactor were investigated experimentally and numerically. A narrow quartz channel having stationary temperature profile along the tube wall given by an external heater was used. Various flame responses were observed by changing an inlet velocity. In low velocity conditions, stable double luminosity peaks were observed. This impiled that two stage ignition which is typical in engine combustion was observed as stationary double weak flames in the present method. One dimensional steady state computation with detailed DME mechanism was conducted to examine the experimental results. Two peaks in CH profile were also found in the low velocity solutions. To examine the validity of the present DME mechanism, computations of flame locations for the case of CH₄-air mixture were conducted. Results showed DME mechanism isn’t capable to reproduce experimental stable branch in low velocity region. And this implies that the DME mechanism needs some modifications.