Microbubbles emission flow boiling in a microchannel and minichannel
Microbubbles emission flow boiling in a microchannel and minichannel
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DOI：
10.1115/icmm2004-2385
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发表时间：
2004
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影响因子：
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通讯作者：
M. Tange;Maki Yuasa;S. Takagi;M. Shoji
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文献类型：
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作者：
M. Tange;Maki Yuasa;S. Takagi;M. Shoji
本文报道了微通道和小通道内微泡喷射沸腾（MEB）的实验研究结果。MEB是在高过冷度、高热流密度条件下的一种沸腾现象。为了了解微沸腾的机理和过程，首先进行了过冷条件下细金属丝上的池沸腾实验。在不同的过冷度条件下，进行了过冷沸腾实验。通过照相观测，研究了气泡直径的分布及其与过冷度的关系。为了更好地了解MEB的过程，并找到MEB的初始过冷，沸腾的声音记录和分析。发现30 ~ 40 K是MEB在细丝上的起始过冷度。在微通道和小通道内的微沸腾实验中，由于过冷流动沸腾时液体温度在较短的长度内升高，因此特别关注沸腾行为的纵向转变。根据实验数据得到了不同通道高度下的沸腾曲线，并测量了整个通道的压降。在微通道中，环形流从下游到上游冲刷整个通道，压降波动较大;而在微通道中，流型分为上游泡状流和下游环形流两个区域。Copyright © 2004 by ASME
This paper reports the results of experimental investigations on microbubbles emission boiling (MEB) in a microchannel and minichannel. MEB is a boiling phenomenon under high subcool and high heat flux condition. To understand the mechanisms and processes of MEB, pool boiling on a thin wire under subcooled condition was firstly performed. Under various subcooling condition, the experiments of subcool boiling were performed. From photographic observation, distributions of bubble diameters and their dependence on subcooling were investigated. To achieve better understanding of the process of MEB and to find the incipient subcooling of MEB, a sound of ebullition was recorded and analyzed. It was found that 30 to 40 K are the incipient subcooling of MEB on the thin wire. In the experiment of MEB in microchannel and minichannel, the special attention was paid to longitudinal transition of boiling behavior, since bulk liquid temperature increases in short length in case of subcooled flow boiling. Boiling curves for various channel height were obtained from experimental data, and pressure drop through whole channel was measured. In a minichannel, annular flow flushed out the whole channel from the downstream to the upstream and the pressure drop fluctuates, while in a microchannel, flow pattern was divided into two regions: bubbly flow in upstream and annular flow in downstream.Copyright © 2004 by ASME