Plasma-assisted Deflagration to Detonation Transition of Dimethyl Ether in a Microchannel*

A plasma microchannel is used to investigate the effect of a uniform nanosecond dielectric barrier discharge (ns-DBD) plasma on deflagration to detonation transition (DDT) for dimethyl ether (DME) in DME:O₂:Ar mixtures at atmospheric pressure and room temperature. Different quantities of discharges are applied across the length of the microchannel ahead of ignition. As the flamefront travels through the plasma region it is imaged using a high speed camera to trace flamefront position and velocity over time as well as to identify DDT. It is shown that a small number of plasma discharge pulses prior to ignition result in reduced DDT onset time and distance by 60% and 40%, respectively, when compared to the results without pre-excitation by ns discharges. The results also show that an increase of plasma discharge pulses results in an extended DDT onset time and distance of 224% and 94%, respectively. The present experiments provide insights to control DDT for applications in advanced propulsion engines.