Abstract: Spray characteristics and evaporating process of dimethyl ether(DME) fuel injected by a single hole nozzle into a constant volume bomb at room temperature were investigated by using the schlieren optical system and a high speed digital camera.Spray development photographs taken at different bomb pressures,injection pressures,nozzle hole diameters and injection quantities were analyzed and compared with those of diesel.Results show that DME spray has the similar development trend to the diesel spray with the variation of back pressure.However,spray tip penetration of DME is shorter and spray cone is wider than those of diesel.DME evaporation is much quicker than diesel spray,and concentration distribution of DME fuel in the spray is more uniform than that in the diesel spray.

Key words: dimethyl ether, spray characteristics, constant volume bomb, schlieren optical system