气流中煤油凝胶液滴变形破碎过程的试验

Experiment on Breakup of a Gelled Kerosene Droplet in Air Jet Flow

关键词:  煤油凝胶  液滴破碎  雾化  高速摄像仪

Key words:  Gelled kerosene  Droplet breakup  Atomization  High-speed camera

摘要:

为了研究煤油凝胶液滴的二次雾化特性，以煤油凝胶和煤油为工质，利用高速摄像系统对均匀气体射流中的液滴变形破碎过程进行了记录测量，获得了不同We下液滴变形破碎的模态特征及转变We，研究了Oh对总破碎时间的影响和We对最大直径变形率的影响。结果表明:在试验工况范围内，煤油凝胶和煤油液滴都依次出现振荡、袋形、多模态破碎模态，但模态特征和转换We不尽相同。煤油液滴总破碎时间随 Oh的增加而增加，而煤油凝胶液滴总破碎时间随Oh的增加先增加后减小再增加。煤油液滴最大直径变形率随We的增加先增加后不变，而煤油凝胶液滴最大直径变形率随We的增加先增加后减小。基于试验数据，分别获得了煤油凝胶和煤油液滴的总破碎时间关于Oh，最大直径变形率关于We的拟合关系式。

Abstract:

In order to investigate the characteristic of gelled kerosene’s secondary atomization， a high speed camera was applied to record and measure the breakup of gelled kerosene and kerosene droplet in the uniform air jet flow. Morphology and transition We of the droplet， impact of Oh on total breakup time and We on the maximum dimensionless diameter deformation ratio were obtained. The results indicate that in the range of test conditions， gelled kerosene and kerosene droplet has the similar vibrational， bag and multimode breakup mode， but not the same at the morphology and transition We. The total breakup time of kerosene droplet increases with the increasing of Oh， while the time of gelled kerosene increases first， then decreases and finally increases again with the increasing of Oh. The maximum dimensionless diameter deformation ratio of kerosene droplet increases first and then does not change with the increasing of We， while the maximum dimensionless diameter deformation ratio of gelled kerosene droplet increases first and then decreases with the increasing of We. Based on the test data， correlations for gelled kerosene and kerosene droplet were proposed to predict the impact of Oh on total breakup time and We on the maximum dimensionless diameter deformation ratio.