含水乙醇多孔直喷喷油器喷雾特性试验研究

Spray Characteristics of Hydrous Ethanol in Multi-hole Direct Injector

摘要:

含水乙醇在具有现有燃料乙醇优点的同时，还可以降低生产过程中的能源消耗和排放。应用高速摄像机和定容弹系统，在五孔直喷汽油喷油器上研究体积分数95%的含水乙醇在不同燃油温度和喷射背压下的喷雾特性，分析其喷雾形态、贯穿距、喷雾锥角、喷雾宽度、喷雾投影面积及闪沸现象，并与纯汽油的喷雾特性进行对比。研究结果表明：含水乙醇喷雾处于冷态射流状态时，贯穿距大于汽油并随背压升高而降低、油温升高而升高；喷雾锥角小于汽油，并随着背压升高而减小；在完全闪沸状态下，喷雾坍塌成单束油束，喷雾贯穿距明显增长，喷雾锥角明显减小，在靠近喷孔区域喷雾宽度增加，远离喷孔区域喷雾宽度减小，此时喷雾投影面积主要受喷射背压影响。

Abstract:

Hydrous ethanol has the advantages of high-octane number and valuable oxygen content， and can reduce the energy consumption and emission in the production process. By application of high-speed cameras and constant volume bomb system， the spray characteristics of 95% hydrous ethanol was studied at different temperatures and fuel injection back pressures with a direct injection gasoline injector with five holes. The spray shape， penetration distance， spray cone angle， spray width， spray projection area， and the flash boiling phenomenon were analyzed and compared with those of pure gasoline. The results show that the penetration distance of hydrous ethanol spray is larger than that of gasoline in cold state， decreases with the increase of back pressure， and increases with the increase of oil temperature. The spray cone angle is smaller than that of gasoline and decreases with the increase of back pressure. In the complete flash boiling state， the spray penetration distance increases， the spray cone angle decreases significantly， the spray width increases in the area near the nozzle， and the spray width decreases in the area far away from the nozzle. Simultaneously， the spray projection area is mainly affected by the spray back pressure.