带膨胀腔喷嘴制冷剂R134a闪蒸喷雾可视化研究  

Visualization of the Flashing Spray Generating by the Expansion-Chamber Nozzle using R134a

作　　者：周致富[1] 白飞龙 王锐[1] 钞睿 陈斌[1] 王国祥[1,2] 

机构地区：[1]西安交通大学动力工程多相流国家重点实验室,西安710049 [2]美国Akron大学机械工程系,akronoh443253903

出　　处：《工程热物理学报》2015年第12期2646-2650,共5页Journal of Engineering Thermophysics

基　　金：国家自然科学基金重点项目(No.51336006);陕西省国际科技合作重点项目(No.2013KW30-05);中央高校基本科研业务费专项基金项目

摘　　要：闪蒸喷雾由于存在特殊的气泡爆裂使得其在较小压力下即能够实现较好的雾化效果。为了探索制冷剂R134a的闪蒸喷雾机理,本文利用高速摄像机对直管石英玻璃喷嘴内部流型以及不同膨胀腔喷嘴的外部喷雾特性进行了可视化观察及量化比较。发现随喷雾压力增大,制冷剂R134a在直管喷嘴内部表现出对称空化、非对称空化和类弹状空化等不同的空化流型,其中对称空化流型对应的雾化锥角基本相同。膨胀腔型喷嘴达到较小喷雾锥角所对应的膨胀腔长径比为1：2~2：1,最佳外部喷雾锥角稳定在70°左右。Flashing spray could generate the desired fine atomization due to the bubble explosion at the nozzle exit at the low injection pressure.This paper presents an experimental study on both the internal flow and the spray pattern outside the nozzle tip so as to further understand the mechanism of the flashing spray.One straight tube nozzle made of the transparent quart glass and five expansion-chamber nozzles with different aspect ratio are employed.The result finds that the internal flow within the straight tube nozzle presents the symmetric cavitation flow,asymmetric cavitation flow and finally the slug cavitation flow with increasing the injection pressure.The spray angle almost remains constant for the slug cavitation flow.For the expansion-chamber nozzles,the spray angle maintains at the relatively smaller values as the aspect ratio of the length to the diameter of the expansion chamber ranges from 1：2 to 2：1,andthe optimal spray angle keeps fluctuating around 70°.

关 键 词：闪蒸喷雾 膨胀腔喷嘴 内部流型 喷雾锥角 

分 类 号：TK121[动力工程及工程热物理—工程热物理]