文氏管中低温流体汽蚀过程可视化实验研究  

Visualization experiment of cavitating flow of cryogenic fluid in venturi tube

作　　者：赵东方[1] 朱佳凯[1] 徐璐[1] 余柳[1] 张小斌[1] 陈建业[1] 王宇辰[1] 

机构地区：[1]浙江大学制冷与低温研究所,浙江省制冷与低温技术重点实验室,杭州310027

出　　处：《低温工程》2015年第6期56-61,共6页Cryogenics

基　　金：国家自然科学基金(N51276157);浙江省杰出青年基金(R15E060001)资助

摘　　要：搭建了一套液氮可视化汽蚀试验台,借助高速摄像机观察了液氮汽蚀文氏管云状汽蚀的非稳态特性。给出了云状汽蚀在不同时刻的汽蚀结构,发现不同于水汽蚀有清晰的气液界面,液氮汽蚀呈两相混合云雾状。云状汽蚀表现为高度的不稳定性,除了尾部汽蚀在二次射流和湍流作用下周期性脱落外,中心汽蚀区还在二次射流作用下做上下周期性摆动。发现二次射流为非轴对称分布,对二次射流导致汽蚀区脱离壁面及摆动机理进行了分析。同时发现汽蚀的非稳态特性导致压力和流量相应非稳态波动,压力在空间波动导致了汽蚀溃灭区气相含量在空间上也呈现大小周期性排列。A visualization experimental device for cavitating flow of liquid nitrogen in Venturi tube was built. The non-steady characteristics of cloud cavitation were captured using a high-speed camera. Cloud cavitation structure at different time was presented. It was found that liquid nitrogen cavitation appears as mist flow,which was different from the water cavitation with clear gas-liquid interface. Cloud cavitation shows highly instability. Periodic shedding in tail cavitation caused by the turbulence and reentrant jet as well as the periodical swing in central cavitation zone resulted from the reentrant jet were observed. The experiments reveal that the reentrant jet is a non-axisymmetric flow and the mechanism of cavitation shedding and swing were analyzed. The pressure and flow rate synchronously fluctuate with the motion of cavitation,and the pressure fluctuate causes the gas phase fraction to distribute periodically in space in the cavitation collapse zone.

关 键 词：液氮 汽蚀 实验 可视化 低温 

分 类 号：TB663[一般工业技术—制冷工程]