Experimental study on effects of ethanol-diesel fuel blended on spray characteristics under ultra-high injection pressure up to 350 MPa

Abstract

In the present study, the atomization characteristics of ethanol-diesel blends fuel spray and shock waves were investigated by using experimental methods under ultra-high injection pressure in the range 200Mpa–350 MPa. A high-speed camera and Schlieren technology were used to visualize the fuel spray morphology and shock waves. The spray tip penetration, velocity and shock wave angle were determined via experimental approaches. Furthermore, the special spray shape under ultra-high injection pressure, such as liquid tail, expanded body and bifurcated structures, was analyzed. To validate the classical spray empirical models, predicted spray penetration results based on two typical models (Dent's and Hiroyasu's model) were compared with experimental data. The results indicated that fuel injection pressure and ethanol volume fraction presented significant effects on the spray evolution. With increasing injection pressure, the spray tip penetration became faster and the induced attached shock waves reveal clearer. The fuel spray jets achieved the larger penetration velocity and more induced shock waves under higher injection pressure or lower ethanol volume fraction.