Influence of transient heat flux on boiling flow pattern in a straight microchannel applied in concentrator photovoltaic systems
Influence of transient heat flux on boiling flow pattern in a straight microchannel applied in concentrator photovoltaic systems
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瞬态热通量对聚光光伏系统直微通道沸腾流型的影响
DOI：
10.1016/j.ijheatmasstransfer.2022.122792
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Ning Mao
中科院分区：
文献类型：
--
作者：
Hao Yu;Jiaojiao Zhuang;Tongling Li;Wenfei Li;Tianbiao He;Ning Mao
聚光光伏（CPV）由于高辐射强度而导致的过热成为阻碍其提高光电效率的关键挑战。为促进CPV的应用，高效散热成为关键技术。同时，微通道流动沸腾作为一种最有前途的高通量设备的强化冷却方法，近年来受到了越来越多的关注。然而，CPV的热流密度波动和不均匀性可能会对用于冷却CPV的微通道沸腾带来挑战。因此，通过对流动沸腾的数值模拟，研究了微通道内去离子水的瞬态流动和相变现象。分析了不同热流突然增加对流动沸腾两相流流型的影响。结果表明，不同的热流密度增加导致不同的流型演变，热流密度突然增加导致流型严重变化，特别是细长受限气泡的波动，可能演变为环状流甚至干涸。气相体积分数显示出高得多的生长速率。当热流密度从97.96 kW/m2增加到580 kW/m2时，最大汽相体积分数从0.104增加到0.8064，干区气泡长度从小于0.3 mm增加到1.5 mm，相变迅速。通过对压力降和蒸汽体积分数变化的分析，将受到突然热流后的时间分为初始期、快速发展期和准稳定期3个阶段。随着热流密度从97.96 kW/m2增加到580 kW/m2，快速发展期的持续时间从0.03 s增加到0.066 s，压降增量明显增大，从2.43 kPa增加到14.51 kPa，微通道内气相体积分数增量从3.3倍增加到25.6倍。表明更强烈的沸腾，以及更高的热通量增加对相变的更深的影响。准稳定段压降波动强度明显增大，由0.025增大到0.193，说明热流密度增加越大，流动沸腾不稳定性越高，应加以控制。
Concentrated photovoltaic (CPV) overheating due to the high radiation intensity became the critical challenge to preventing its benefits in advancing the photoelectric efficiency. To promote the application of CPV, efficient heat dissipation becomes the key technology. Meanwhile, microchannel flow boiling, as one of the most promising solution to advance cooling of high-flux equipment, has attracted increasing attentions in recent years. However, the fluctuating and non-uniform heat fluxes of CPVs may lead to challenges to microchannel boiling for cooling CPV. Therefore, the transient flow and phase change phenomenon in a microchannel with deionized (DI) water was studied through a numerical modeling on flow boiling. The effects of different sudden heat flux increases on flow boiling two-phase flow pattern were analyzed. It was found that different heat flux increase resulted to different flow pattern evolutions, a much higher sudden increase in heat flux leaded to serious variation of flow pattern, especially the fluctuation of elongated restricted bubbles, which may evolve to annular flow or even dry-out. The vapor phase volume fraction showed a much higher growth rate. When the heat flux increase was raised from 97.96 kW/m2to 580 kW/m2, the maximum vapor phase volume fraction was increased from 0.104 to 0.8064, and the bubble length increased from smaller than 0.3 mm to 1.5 mm in the dry zone, indicating rapid phase change. Based on analysis on pressure drop and vapor volume fraction variation, the period after receiving sudden heat flux was divided into three stages: initial period, rapid development period, and quasi-stable period. With the rising of heat flux increase from 97.96 to 580 kW/m2, the duration of rapid development period was increased from 0.03 s to 0.066 s, the pressure drop increase was obviously enlarged, from 2.43 kPa to 14.51 kPa, and the vapor phase volume fraction increase in the microchannel was raised by 3.3 times to 25.6 times, indicating more intensive boiling, and deeper effect of higher heat flux increase on the phase change. In addition, the fluctuation intensity of pressure drop in the quasi-stable period was obviously increased from 0.025 to 0.193, demonstrating the advancement in flow boiling instability under higher heat flux increase, which should be controlled.
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影响因子：
11.2
作者：
A. Radwan;S. Ookawara;Mahmoud A. Ahmed
通讯作者：
A. Radwan;S. Ookawara;Mahmoud A. Ahmed
DOI：
10.1299/jsmemagazine.37.206_367
发表时间：
1966-12
期刊：
Journal of the Society of Mechanical Engineers, Japan
影响因子：
--
作者：
S. Nukiyama
通讯作者：
S. Nukiyama
影响因子：
4.1
作者：
BRACKBILL, JU;KOTHE, DB;ZEMACH, C
通讯作者：
ZEMACH, C
可变流体热性质对矩形微通道流动和传热的影响
DOI：
--
发表时间：
2008
期刊：
影响因子：
--
作者：
H. Yun;Lin Cheng;Lq Wang
通讯作者：
Lq Wang
应用于高聚光光伏热混合系统的两相流微通道散热器的研制
DOI：
--
发表时间：
2020
期刊：
影响因子：
--
作者：
党 超鋲; 洪 思慧;党 超鋲;党 超鋲;Chaobin Dang
通讯作者：
Chaobin Dang