高压燃油诱导激波对喷雾演化规律的影响

Effect of Shock Wave Induced by High-Pressure Fuel Injection on the Evolution of Diesel Spray

采用纹影法对高压燃油喷射下的诱导激波现象进行可视化试验,结合喷油规律曲线,分析了激波对喷雾演化规律及雾化特性的影响.结果表明:在相同的燃油喷射压力及背景密度条件下,激波的产生和传播对喷雾贯穿距离的发展具有促进作用,但是对喷雾径向发展影响不大.激波对喷雾轴向的促进会进一步增强喷雾对空气的卷吸作用,有助于喷雾的快速雾化.同时,笔者提出了燃油喷射激波角计算的经验公式,实现了燃油喷射过程激波角的预测,预测结果与试验结果吻合较好.

The schlieren imaging method was used to visualize the induced shock wave phenomenon under highpressure fuel injection.Combined with the shape of the fuel injection rate,the effect of shock wave on spray evolu-tion and atomization characteristics was analyzed.The results show that the generation and propagation of the shock wave promote the spray tip penetration under the same fuel injection pressure and ambient density.However,the shock wave has little effect on the spray development in the radial direction.The promotion of the spray in the axial direction by the shock wave will further enhance the air entrainment effect of the spray,leading to better atomization.In addition,an empirical correlation for calculating the angle of the shock wave was proposed to realize the prediction of the shock wave during the fuel injection process.The calculated results are found to be in good agreement with the experimental data.