摘要
为探究低温风洞中液氮液滴的破碎特性并阐明其破碎机理,基于耦合水平集流体体积函数(CLSVOF)方法,采用自适应局部网格加密技术,构建了二维液氮液滴破碎模型,对比了液氮液滴与常温液滴的形态演变规律,计算分析了韦伯数(We)对液氮液滴形态、变形系数及时间特性的影响规律。模拟结果表明:液氮液滴的We高于常温液滴,且更容易发生变形和破碎;随着We的增大,液氮液滴依次发生袋状破碎、多模式破碎和剪切破碎;液滴迎风面和背风面的压差均随时间呈现先增大后减小的规律,发生转变的原因是袋状结构形成或边缘液滴颗粒脱落;不同液氮液滴破碎模式下,变形系数的变化规律差异明显;液氮液滴无量纲初始破碎时间随We的增大而减小,在0<We<100时,临界变形系数维持在2.6附近。研究结果可为低温风洞中液氮喷雾冷却系统的优化提供理论依据。
To explore the breakup characteristics of liquid nitrogen droplets in a cryogenic wind tunnel and determine the underlying mechanism,a two-dimensional liquid nitrogen droplet breakup model is established adopting the coupled level-set and volume of fluid(CLSVOF)method and adaptive local mesh refinement technology.The morphological evolution patterns of liquid nitrogen droplets and normal temperature droplets are compared,and the effects of We on the morphology,deformation coefficient and temporal features of liquid nitrogen droplets are analyzed.The results show that compared with normal temperature droplets,liquid nitrogen droplets have a higher We,which makes them more prone to deformation and fragmentation.As the We increases,the droplets sequentially undergo bag breakup,multimode breakup and shear breakup.For the three different breakup modes,the pressure difference between windward and leeward sides of the liquid nitrogen droplet increases first and then decreases with time.This is attributed to the formation of bag structures or the separation of droplets from the edge.Under different breakup modes of liquid nitrogen droplets,the pattern of deformation coefficient is distinctly different.The dimensionless initial breakup time of the droplet decreases with the increase of We.In the range of 0<We<100,the critical deformation coefficient is maintained around 2.6.This study can provide a theoretical basis for the optimization of liquid nitrogen spray cooling system in cryogenic wind tunnel.
作者
苗庆硕
魏震
陈佳军
张海洋
钟富豪
郑勉
刘秀芳
MIAO Qingshuo;WEI Zhen;CHEN Jiajun;ZHANG Haiyang;ZHONG Fuhao;ZHENG Mian;LIU Xiufang(School of Energy and Power Engineering,Xi’an Jiaotong University,Xi’an 710049,China;Facility Design and Instrumentation Institute,China Aerodynamics Research and Development Center,Mianyang,Sichuan 621000,China)
出处
《西安交通大学学报》
EI
CAS
CSCD
北大核心
2024年第2期91-99,共9页
Journal of Xi'an Jiaotong University
基金
国家自然科学基金资助项目(52076164)
国家科技重大专项资助项目(J2019-Ⅲ-0010-0054)
结冰与防除冰重点实验室开放课题资助项目(IADL20220107)。
关键词
低温风洞
液氮液滴
破碎特性
破碎模式
变形系数
cryogenic wind tunnel
liquid nitrogen droplets
breakup characteristics
breakup modes
deformation coefficient
作者简介
苗庆硕(1999-),男,硕士生;通信作者:刘秀芳,女,副教授,博士生导师。
