Macroscopic spray characteristics of iso-octane, ethanol, gasoline and methanol from a multi-hole injector under flash boiling conditions
Macroscopic spray characteristics of iso-octane, ethanol, gasoline and methanol from a multi-hole injector under flash boiling conditions
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DOI：
10.1016/j.fuel.2021.121820
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发表时间：
2021-09-02
期刊：
影响因子：
7.4
通讯作者：
Li, Yanfei
中科院分区：
文献类型：
--
作者：
Badawy, Tawfik;Xu, Hongming;Li, Yanfei
本研究旨在研究燃油温度、环境压力和燃油性质对六孔汽油直喷器喷雾特性的影响。利用高速成像技术在光学容器中验证了各种燃料(包括异辛烷、汽油、甲醇和乙醇)在各种操作条件下的喷雾结构变化。这些结构参数与代表过热度的环境压力与饱和压力之比(P-a/P-S)相关。在150巴的恒定压力下注入燃料，燃料温度在25到120摄氏度之间，而环境压力从0.1到1巴。结果表明，对于所有的燃料，喷雾宽度都随着(Pa/Ps)的减小而减小，相邻的羽流坍塌成单一的整体。此外，在很低的压力下(Pa/Ps=0.065)，喷雾变长，对于异辛烷，燃油喷雾向喷油器中心线方向收缩，形状像鱼形，喷嘴尖端锐化。乙醇、甲醇和汽油的喷雾锥角随Pa/Ps比从1减小到0.16而减小，但乙醇的锥角随着Pa/Ps的减小先增大后减小。当Pa/Ps值从0.16时降至0.065时，锥角显著增大。对于异辛烷，其行为是混沌的，并且不遵循任何特定的趋势，随着PA/Ps的降低。此外，在Pa/Ps比时，在原始喷雾流之间的间隙中还观察到了间隙流的出现
The present study is geared towards the investigation of the impact of fuel temperature, ambient pressure, and fuel properties on the spray characteristics of a 6-hole gasoline direct injector. High speed imaging is employed to verify the spray structural variation of various fuels including iso-octane, gasoline, methanol, and ethanol over wide range of operating conditions in an optical vessel. These structural parameters were correlated to the ratio of the ambient to saturation pressure ratio (P-a/P-s) that represents the superheated degree. At a constant pressure of 150 bar the fuel was injected, and the fuel temperature ranged between 25 and 120 degrees C, whilst the ambient pressure ranged from 0.1 to 1 bar. The results indicated that for all the fuels, the spray width was reduced, and the adjacent plumes collapsed into single bulk as the (Pa/Ps) decreased. Furthermore, at very low (Pa/Ps = 0.065), the spray getting longer, and for iso-octane the fuel spray shrinkage toward the injector centreline and shaped like a Fish with sharpen spray tip. The spray cone angle for ethanol, methanol, and gasoline was reduced when the Pa/Ps ratio was decreased from 1 to 0.16 with the exception that at Pa/Ps = 0.54 for ethanol the cone angle was increased and then decreased with the reduction of Pa/Ps. Then a massive increase in the cone angle was noticed by reducing the Pa/Ps ratio reduced from 0.16 to 0.065. For iso-octane, the behaviour is chaotic and not follow any specific trend with the reduction of Pa/Ps. Furthermore, the appearance of interstitial streams in the gaps between the original spray streams was noticed at Pa/Ps ratio