高温高压下平板预膜喷嘴初次雾化试验

为了深入探究预膜喷嘴燃油初次雾化机理，试验研究了高温高压条件下不同工况参数对平板预膜喷嘴初次雾化特性的影响规律。采用高速摄影可视化技术和马尔文粒度仪获取了预膜平板液膜厚度、液膜波动形态以及索泰尔平均直径（SMD）等雾化特性。利用图像后处理技术提取液膜厚度，试验结果表明:液膜厚度随进气压力、进气温度和进口韦伯数的增加而减小，随燃油流量增加而增加。采用本征正交分解（POD）对液膜波动主要模态时间系数进行快速傅里叶变换，结果表明在相同工况下，液膜波动频率表现出和液膜厚度变化相反的结果。当进气压力改变时，进口韦伯数保持不变，试验结果表明进气压力对最终液滴平均尺寸影响不明显，证实了进口韦伯数是更适合的表征燃油雾化效果的参数，在工况范围内液滴尺寸随着进口韦伯数的增加而减小。 

Experiment on primary atomization of flat prefilm nozzle under high temperature and high pressure

In order to deeply explore the primary atomization mechanism of prefilm nozzle，the influences of different working parameters on the primary atomization characteristics of flat prefilm nozzle under high temperature and high pressure were experimentally studied.The atomization characteristics such as liquid film thickness，liquid film fluctuation pattern and Sauter mean diameter （SMD） of the prefilm plate were obtained by high-speed photography visualization technology and Malvern particle size analyzer.The film thickness of extraction solution was obtained by image post-processing technology.The experimental results showed that the film thickness decreased with the increase of inlet pressure，inlet temperature and inlet Weber number，and increased with the increase of fuel flow rate.Proper orthogonal decomposition （POD） was used to perform fast Fourier transform on the main mode time coefficients of liquid film fluctuation.The experimental results also showed that under the same working conditions，the fluctuation frequency of liquid film presented opposite result with the change of liquid film thickness.When the inlet pressure changed，the inlet Weber number kept unchanged.The experimental results showed that the inlet pressure had no obvious effect on the average size of the final droplet，demonstrating that the inlet Weber number is more suitable for characterizing the fuel atomization effect，and the droplet size decreases with the increase of inlet Weber number.