基于超高燃油喷射压力的喷雾特性试验研究与模型修正

Experimental study and model modification of spray characteristics based on super-high pressure

为了研究超高压喷射条件下二次破碎喷雾模型对燃油雾化特性的影响,在AVL FIRE软件平台上对燃油喷雾过程进行数值模拟,搭建可视化喷雾闪光摄影试验台架。基于超高的燃油喷射压力对燃油的雾束发展形态进行了图像采集,利用试验结果对二次破碎喷雾模型进行修正,分析模型中主要参数对燃油雾化特性的影响。结果表明:KH波破碎时间常数C_2的减小有利于缩短喷雾贯穿距离,同时避免发生燃油撞壁现象;随着RT波波长常数C_4的增大,二次破碎新生油滴的直径变大,雾化效果变差;由于首次破碎过程对二次破碎过程的制约作用,导致C_4对喷雾计算结果的影响不像C_2那样显著。

In order to study the influence of the twice breakup spray model on the atomization characteristics under the condition of super-high pressure injection, the fuel spraying process was simulated on the AVL FIRE sottware platform. The visual spray flash photography test bench was set up. The image acquisition of the spray development form of fuel was carried out. The twice breakup spray model was modified by the experimental results. The influence of main parameters on the atomization characteristics was analyzed. The results show that the decrease of KH wave breakup time constant C2 is conducive to shorten the spray penetration distance and avoid the fuel impinging wall phenomenon; With the increase of the RT wavelength constant C4, the diameter of the new oil drop of twice breakup becomes larger and the atomization effect becomes worse. Because of the restriction of the first breakup process to the second breakup process, the impact of Ca on the spray calculation results is not as significant as C2.