化工学报Issue(z1)：66-70,5.DOI:10.11949/j.issn.0438-1157.20170462
多微通道内两相流动阻力特性及气泡行为
Characteristics of two-phase flow resistance and bubble behavior in microchannels
摘要
Abstract
The characteristics of two-phase flow resistance and bubble behavior had been experimentally investigated in a microchannel heat sink containing 14 parallel 0.15 mm× 0.25 mm rectangular microchannels with hydraulic diameter of Dh=187.5 μm by using deionized water as working fluid.The experimental results revealed that vapor phase gradually increase with the increase of heat flux under constant inlet temperature and mass flux,leading to the increase of pressure drop in parallel multiple microchannel.When keeping the heat flux and inlet temperature constant,the pressure drop exhibited a trend of first decrease and then increase with the increase of mass flux.In addition,the lowest point in the curve of pressure drop vs mass flux (Δpexp vs G) is considered to be the starting point of the static flow instability (namely,OFI point).The characteristics of four different bubble behavior are studied by basing on the help of visual image and bubble dynamics theory.It is found that due to the effects of the interaction of buoyancy and flow inertia force,the bubble was rapidly cleared at the initial stage of bubble nucleation.When the bubble size is approximately equal to the height of the channel,the bubble enter the local confined growth phase,leading to the increase of viscous resistance between the bubble and the surface of wall.And under the influence of heat flux,the bubble continues to grow and is limited in the width direction,so that the bubble's growth was completely confined both at height and width direction.Thereafter,the bubble gradually grew and elongated as well as flowed downstream.Moreover,when the surface tension is insufficient to maintain the liquid bridge between two adjacent bubble,the liquid bridge broke and resulted in bubbles merging.It is more interesting that due to the influence of the downstream bubble reversal flow and the flow inertia force,The upstream bubble is gradually compressed,leading to the velocity of the bubble tail lower than that of the bubble head.Finally,by using the current pressure drop data to verify the prediction accuracy of Kim & Mudawar correlation,it is found that the Kim & Mudawar correlation can only predict the variation trend of pressure drop,but can not predict the pressure drop value.关键词
微通道/两相流/可视化/压降/OFI点/气泡/动力学Key words
microchannels/two-phase flow/visualization/pressure drop/OFI point/bubble/dynamics分类
能源科技引用本文复制引用
严润刚,潘良明,何辉,黄豪杰,李鹏斐..多微通道内两相流动阻力特性及气泡行为[J].化工学报,2017,(z1):66-70,5.基金项目
国家自然科学基金面上项目(51376201,51676020).supported by the National Natural Science Foundation of China (51376201,51676020). （51376201,51676020）
