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本文在定容弹中用高速摄影研究了环境气体温度和密度对喷射压力为75～134MPa的柴油机喷雾贯穿距离、喷雾角及碰壁过程的影响.结果表明,环境温度对高压喷雾的影响远比对常规压力喷雾显著.环境温度升高后,高压喷雾的贯穿距离有所减小,而喷雾角则明显增大,在高温高密度下,喷雾角可增至30°以上.高压喷雾与常温壁面碰撞时,几乎看不到反跳现象,但在壁温较高时,壁面附近将有较浓密的液雾,且在液雾和壁面间有一蒸气层.环境密度对高压喷雾的影响在定性上与对常规压力喷雾相同.当喷射压力由75MPa提高到134MPa时,贯穿距离反而有所减小.本文根据这一实验结果提出了一个考虑了喷射压力和温度影响的计算贯穿距离的经验公式.
In this paper, the effect of ambient temperature and density on the spray penetration, spray angle and wall-in process of diesel engine with injection pressure of 75 ~ 134MPa was studied by high-speed photography in fixed volume bombardment.The results showed that the effect of ambient temperature on high pressure spray was far more than that of Conventional pressure spray is significant.When the ambient temperature increases, the penetration of high-pressure spray decreases, while the spray angle increases significantly, under high temperature and high density, the spray angle can be increased to more than 30 °.High-pressure spray and ambient temperature wall collision , Almost no rebound phenomenon is observed, but at a higher wall temperature, there will be a thicker liquid mist near the wall and a vapor layer between the liquid mist and the wall. The effect of ambient density on the high-pressure spray is qualitatively related to When the injection pressure is increased from 75MPa to 134MPa, the through distance will be reduced. Based on the experimental results, an empirical formula for calculating the penetration through consideration of injection pressure and temperature is proposed.