波形微通道流动沸腾换热特性的数值模拟  

Numerical simulation on flow boiling heat transfer characteristics in sinusoidal-wavy microchannel

作　　者：王迎慧[1] 皇甫启捷 WANG Yinghui;HUANGFU Qijie(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

出　　处：《江苏大学学报（自然科学版）》2019年第4期397-403,共7页Journal of Jiangsu University：Natural Science Edition

基　　金：国家自然科学基金资助项目(51276039)

摘　　要：提出一种壁面为正弦波形结构的微通道,应用VOF模型和用户自定义函数,着重对波形微通道内的流动沸腾换热过程进行数值模拟.对比波形微通道和平直微通道内的汽泡变化、流动沸腾换热效果和可靠性的差异,分析波形结构对微通道流动沸腾换热的影响.对比发现:波形结构可以促进汽泡脱离受热壁面,维持核态沸腾,避免局部干涸,保证汽液两相流动的可靠性.研究结果表明:增大波幅和减小波距均可强化波形微通道的沸腾换热;波幅扩大到4倍(从20μm增加到80μm),沸腾换热系数提高26.5%,流动阻力升高24.0%;波距缩小到1/4(由2.0 mm减少到0.5 mm),沸腾换热系数提高16.0%,流动阻力升高40.0%;波幅对沸腾换热系数的影响较大,而波距对流动阻力的影响较大,但过大的波幅和过小的波距会引起局部干涸,造成传热恶化,不利于可靠传热.The numerical simulation was performed to study the flow boiling heat transfer characteristics in the sinusoidal-wavy microchannel by volume of fluid(VOF)model and user-defined functions(UDF).The variation of bubbles behaviors,the effect of flow boiling heat transfer and the reliability in the horizontal straight microchannel were compared with those in the wavy microchannel,and the influences of wave structure on flow boiling heat transfer characteristics were analyzed.The comparisons show that the wave structure can promote bubbles detachment with maintained nucleate boiling and avoid local dryness of heating wall to ensure the reliability of vapor-liquid two-phase flow.The flow boiling heat transfer in the microchannel can be enhanced by increasing the wave amplitude or decreasing the pitch of waves.Increasing the wave amplitude by 4 times from 20μm to 80μm can increase the boiling heat transfer coefficient by 26.5%,and the pressure drop of the two-phase flow is increased by 24.0%in the meantime.While decreasing the pitch of waves by 4 times from 2.0 mm to 0.5 mm can increase the boiling heat transfer coefficient by 16.0%,and the pressure drop is increased about 40.0%.The wave amplitude has great influence on the flow boiling heat transfer coefficient,while the pitch of waves has great influence on the flow resistance.However,too big wave amplitude or too small pitch can result in heat transfer deterioration,which is not good for stable and reliable heat transfer in microchannel.

关 键 词：波形微通道 流动沸腾换热 汽泡 传热可靠性 数值模拟 

分 类 号：TK121[动力工程及工程热物理—工程热物理]