高压柴油射流激波特性影响研究

Study on Influencing Parameters of Shock Wave of High-Pressure Diesel Jets

针对高压柴油射流诱导激波开展了研究,通过采用纹影法对不同环境气体介质、激波态喷雾宏观特性、不同环境密度对激波的影响进行研究。结果表明:喷射压力为60 MPa的情况下,当环境介质气体为N2时,并未出现激波现象,而当环境介质更换为SF6时,出现了较明显的激波现象。当喷射压力提高至120 MPa时,2种气体介质中均出现了激波现象。喷雾宏观特性在产生激波后以及激波脱离喷雾体后均没有出现明显的变化,这可能表明即使激波可能导致环境气体速度和压力的变化,但其对喷雾发展的影响并不显著。环境密度对喷雾前端速度最大值、激波的类型以及激波与喷雾体分离时刻有显著的影响。

The shock wave generated by high pressure diesel spray has been investigated,and the influences of ambient gas property,the progress of the spray,and ambient gas density on shock wave have been analyzed by using schlieren imaging method.The results show that:the shock wave can only be observed in SF6 when the injection pressure is 60 MPa,while can be observed both in SF6 and N2 with increasing the injection pressure to 120 MPa.The generation of shock wave and the detachment of shock wave from the spray tip show little influence on the spray macroscopic characteristic,which may indicates that even if the shock wave may result in the variations of gas speed and pressure,the impact of shock wave on the spray macroscopic characteristic during the injection process is not distinct.The ambient gas density have a significant effect on the maximum of spray tip velocity,types of shock wave and the detachment timing of shock wave from the spray tip.