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燃油喷嘴内的液体流动在一定条件下会形成空化,进而影响喷嘴的雾化效果。应用高速摄像仪对圆形喷嘴内的空化以及喷口外的雾化进行了实验研究。实验所用喷嘴直径包括0.5mm,1.0mm,1.5mm和2.0mm,其中直径为1.5mm的喷嘴的长径比从2变化到9,实验工质为纯净水。实验发现,喷嘴内空化的形成是动态的,空化长度出现高频低幅脉动。对于喷嘴的收缩类型研究发现,急收型相比渐收型更易形成空化,并有增强雾化的效果。长径比相同的喷嘴,直径越大,达到超空化的喷射压力越大,雾化锥角也越大;直径相同的喷嘴,随长径比的增加,达到超空化的空化数逐渐减小,但射流的喷雾锥角没有明显的变化趋势,均在10°到20°之间。对比破碎模式规律,除了0.5mm的喷嘴外,所有喷嘴达到超空化后均为雾化模式。
The liquid flow in the fuel nozzle will form cavitation under certain conditions, thereby affecting the atomization effect of the nozzle. The use of high-speed camera cavitation within the circular nozzle and atomization outside the nozzle was studied. Experimental nozzle diameter used include 0.5mm, 1.0mm, 1.5mm and 2.0mm, wherein the diameter of 1.5mm nozzle aspect ratio from 2 to 9, the experimental working fluid is pure water. It was found that the formation of cavitation in the nozzle was dynamic and the cavitation length appeared high frequency and low amplitude pulsation. For the nozzle type of contraction study found that emergency received type is easier to form than the gradual cavitation, and enhance the effect of atomization. The larger the diameter of the nozzle is, the larger the diameter is and the larger the injection pressure to achieve hyper-cavitation is, the larger the atomization cone angle is. The nozzle with the same diameter will increase its cavitation number as the aspect ratio increases Decreases, but there is no obvious change tendency of jet spray cone angle, all between 10 ° and 20 °. Compared with the broken mode law, in addition to 0.5mm nozzle, all the nozzles to achieve cavitation after cavitation mode.