燃烧室背压对压力涡流喷嘴喷雾特性的影响

Spray Characteristics of Pressure-swirl Nozzle at Different Ambient Pressures of Combustion Chamber

采用高速摄影技术、激光测粒仪和PIV测试技术系统试验研究了燃烧室背压对斯特林发动机压力涡流喷嘴喷雾形成过程、贯穿距离增长规律、喷雾锥角、液滴粒径和喷雾流场的影响。结果表明,燃烧室背压的增加使喷雾形状更加致密,贯穿距离的增加变缓,液滴平均速度增加,索特平均直径增加。当燃烧室背压大于1.0-1.5 MPa之间的一个临界值时,其对喷雾锥角没有影响,小于此临界值,燃烧室背压的增加会使喷雾锥角急剧降低。

The spray characteristics of pressure-swirl nozzle used in Stirling engine was studied by way of the experiment under high ambient pressures（up to 2.8MPa）.The high-speed video imaging technique,FAM（Fraunhofer and Mie） laser drop size analyzer,and PIV（particle image velocimetry） test equipment were used for experimental measurements.Experimental results showed that the spray structure at higher ambient pressure was more compact.The vortex cloud was found at the leading edge at high ambient pressure.Spray cone angle was independent of ambient pressure after a value between 1.0-1.5MPa.The Sauter mean diameter（SMD） and the drop velocity became larger at high ambient pressure conditions.Finally,a vortex was found in the center of the spray and this region moved to the downstream of the spray as the ambient pressure increased.