Experimental study of dimethyl ether (DME) in a swirl-stabilized spray combustor

Dimethyl ether (DME) is an environmentally benign compound that has been proposed as an alternative to diesel due to its high cetane number. DME has a high oxygen content and no C-C bonds, which leads to clean combustion, and it can be handled like LPG since its vapor pressure is between that of propane and butane. Tests have also shown that DME is an excellent gas turbine fuel with emissions comparable to those of natural gas. In the current study, DME was studied in a swirl-stabilized spray combustor. The fuel was stored and injected into the burner as a liquefied gas. High-speed videography was used to observe the vaporization of the fuel. Size and 2-D velocity distributions were obtained across the combustor with a Phase Doppler Particle Analyzer (PDPA), and temperature distributions were obtained via thermocouple. When injected, a portion of the fuel flashes into vapor as it leaves the nozzle, while the remaining fuel forms a uniform spray with a Sauter mean diameter (SMD) of under 12 µm and with velocities between 20 and 50 m/s. The peak flame temperature is 1520 °C and the exhaust temperature is around 1200 °C. Stable combustion could be easily obtained and no yellow luminosity from soot was observed under any condition.