柴油机交叉孔喷嘴自由喷雾特性实验研究

Experimental Study on the Free Spray Characteristics of Intersecting-hole Nozzle in Diesel Engine

为探究喷射压力、温度、背压和交叉角对交叉孔喷嘴喷雾性状的影响,基于可视化定容弹系统,利用阴影法,研究了单孔与不同角度交叉孔喷嘴的喷雾特性。结果表明:与单孔喷嘴相比,交叉孔喷嘴的喷雾贯穿距较小,喷雾锥角较大,且随着交叉角的增大,差距更加明显;随着喷射压力的提高,交叉孔与单孔喷嘴的喷雾贯穿距的差别减小,交叉角较大的交叉孔喷嘴的喷雾锥角增大;低蒸发温度下,喷射压力对喷雾前期贯穿距的影响较大,随着蒸发温度升高,交叉孔与单孔喷嘴喷雾锥角差距增大,喷雾前期贯穿距差别减小;背压提高后,总的趋势是喷雾贯穿距缩短,而喷雾锥角增大;与单孔喷嘴相比,它对交叉孔喷嘴的喷雾特性影响更大。

In order to explore the influence of injection pressure, temperature, back pressure and intersecting an-gle on spray pattern of intersecting-hole nozzle, the spray characteristics of both single-hole nozzle and intersetting-hole nozzles are studied in a visible constant volume chamber by using shadowgraph method. The results show that compared with single-hole nozzle, the spray penetrations of intersecting-hole nozzles are smaller and their spray cone angles are larger, and with the increase of the intersecting-angle, the differences become more obvious. With the increase of injection pressure, the differences of spray penetrations between single-hole nozzle and intersec- ting-hole nozzle reduce, and the larger the intersecting angle, the larger the spray cone angle. At low evaporation temperature, the effects of spray pressure on spray penetration at early stage are more significant, and as the temper- ature rises, the differences in spray cone angle between single-hole and intersecting-hole nozzles increase, while the differences in spray penetration decrease at early stage. With back pressure going up, the overall trend is the shortening of spray penetration and the rising of spray cone angle, and it has greater influence on the spray characteristics of intersecting-hole nozzle than those of single-hole nozzle.