Experimental Study on the Combustion Process of Dimethyl Ether (DME) 2003-01-3194
Studies on combustion process of Dimethyl Ether (DME) were carried out on a constant volume combustion bomb (CVCB) and a visualization engine, and the photograph of combustion of DME was taken by high speed digital CCD. The results show that the ignition delay of DME is shorter than that of diesel fuel. When the fuel delivery amounts of DME and diesel in volume are the same, the combustion duration of DME is shorter than that of diesel fuel, and the flame temperature of DME is lower than that of diesel. At the end of combustion, the second injection occurred. The results of high-speed photograph in visualization engine show that, as soon as DME leaves the nozzle, it evaporates rapidly, and under the effect of air swirl, the spray“core” is blown off. Compared to diesel, the penetration of DME is shorter, and the wall combustion of DME is apparently smaller. Additionally, DME has shorter ignition delay, the ignition position is nearer the wall, the area of ignition is larger at the beginning of combustion, and the flame propagates faster. The pressure delay of DME is shorter than the illumination delay, while the pressure delay of diesel is almost the same as the illumination delay. Meanwhile DME and diesel have almost the same thermal efficiency.