高韦伯数液滴撞壁诱导的中间射流破碎现象

In consideration of the problem of fuel film on the cylinder wall in an internal combustion engine,the process of droplet impact was simulated in this paper. A test system was designed and developed in which a gas-driven single-droplet impacted the hot wall at high speeds.The effect of high-speed droplet impact on the secondary atomization was studied,and the influence of wall temperature on the impact effect was also considered. Compared with the Weber number range of mostly 20-1000 from current studies on droplet impact,the speed of droplets accelerated to 10.8m/s by using the driving gas(i.e.,nitrogen),thereby generating droplets with a Weber number of up to 4057. The phenomenon of jet breakage occurred when the Weber number grew to a certain value,so the thermal effect was not the only inducing factor. As the Weber number grew,the jet height and the number of resulting secondary droplets increased accordingly. With the growth of wall temperature,the Weber number decreased as the central jet occurred. Under the condition of high Weber number,no obvious Leidenfrost phenomenon occurred at the temperature much higher than the Leidenfrost temperature of water.