Ω型凹槽微通道内的汽泡行为及流动沸腾特性  

Bubble behavior and flow boiling characteristics in microchannels withΩ-grooves

作　　者：王迎慧[1] 张亮[1] WANG Yinghui;ZHANG Liang(School of Energy and Power Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China)

机构地区：[1]江苏大学能源与动力工程学院,江苏镇江212013

出　　处：《江苏大学学报（自然科学版）》2020年第4期405-410,共6页Journal of Jiangsu University：Natural Science Edition

基　　金：国家自然科学基金资助项目(51576091)。

摘　　要：针对Ω型凹槽微通道内流动沸腾,运用VOF(volume of fluid)模型和用户自定义函数,对微通道内发生的一系列汽泡行为进行了数值模拟.结合Ω型凹槽微通道内汽泡成核生长、聚并、脱离的动态演变过程,分析Ω型凹槽微通道流动沸腾换热的特点.结果表明:与平直微通道相比,Ω型凹槽微通道内的汽泡行为较为不同,汽泡脱离周期缩短,主流区温度降低,汽泡与受热壁面之间存在液体薄层,有助于提升流动沸腾换热的稳定性、可靠性;不同的凹槽结构(凹槽深度H、凹腔直径D)强化传热效果不同;H=50μm,D=80μm的Ω型凹槽微通道,其换热系数最高;H=30μm,D=50μm的凹槽微通道则对应最低的换热系数;凹腔直径对微通道内的压降影响较为明显,较大的凹腔直径对应较高的压力损失.To investigate the flow boiling inΩ-grooved microchannels,the volume of fluid(VOF)model and the user-defined functions were used to numerically simulate a series of bubble behavior in the microchannels.Combined with the dynamic evolution process of bubble nucleation,coalescence and detachment in theΩ-grooved microchannels,the characteristics of flow boiling heat transfer were analyzed.The results show that compared with the straight microchannels,the bubble evolution behavior inΩ-grooved microchannels appears quite different.Besides higher frequency of bubble detachment,the temperature of liquid in the main stream is lower,and there exists thin liquid film between bubbles and heated wall.These features can improve the stability and reliability of flow boiling heat transfer in microchannels to a certain extent.The groove structures with different groove depth H and cavity diameter D have effects on the heat transfer enhancement.TheΩ-grooved microchannel with H of 50μm and D of 80μm shows the highest heat transfer coefficient,while the lowest heat transfer coefficient emerges in theΩ-grooved microchannel with H of 30μm and D of 50μm.The diameter ofΩ-groove has significant effect on the pressure drop in the microchannels,and the larger diameter corresponds to higher pressure loss.

关 键 词：Ω型凹槽 微通道 流动沸腾 汽泡 数值模拟 

分 类 号：TK124[动力工程及工程热物理—工程热物理]