Experimental study on compact plate loop heat pipe

doi:10.11949/0438-1157.20201452

Abstract

Abstract:

Loop heat pipes (LHP) have great application prospects in the cooling of electronic elements duo to their compactness and high efficiency. This paper designed a compact LHP with capillary core flat-over evaporator and investigated its start-up and heat transfer performance under various conditions experimentally. The results show that a higher heating power and higher refrigerant charge are beneficial with the LHP starts up stably, while it happens oscillation during the start-up process with low heat load and charge ratio. As for the heat transfer performance, there is an optimal refrigerant filling ratio corresponding to the heat load where the LHP shows the best cooling performance. The optimal filling ratio is small when the heat load is relatively low, and the performance will be better if the refrigerant charge is relatively large under a condition with high heat load.

Key words: compact, flat-over evaporator, loop heat pipe, heat transfer, evaporation, porous media

摘要：

环路热管因其紧凑、高效等优势在电子元件冷却方面十分具有应用前景。实验研究了一种紧凑型平板环路热管在不同工况下的启动特性和传热特性。结果显示部分低加热功率和充液率下的启动出现振荡，高加热功率和较高充液率有利于环路热管平稳启动。总结了温度振荡现象出现的工况范围。传热特性方面，存在一个最优充液率使热管散热性能最佳，这个最优充液率与散热负荷有关。低负荷时，最优充液率较低；高负荷时，最优充液率较高。

关键词: 紧凑型, 平板蒸发器, 环路热管, 传热, 蒸发, 多孔介质

CLC Number:

TK 172.4

TIAN Yaling, ZHANG Hainan, XU Hongbo, TIAN Changqing. Experimental study on compact plate loop heat pipe[J]. CIESC Journal, 2021, 72(6): 3288-3295.

田亚玲, 张海南, 徐洪波, 田长青. 紧凑型平板环路热管实验研究[J]. 化工学报, 2021, 72(6): 3288-3295.

Figures/Tables 8

Fig.1 Compact loop heat pipe experimental system

Table 1 The specification of the measuring instruments

物理量	测量仪器	量程	精度
体积	注射泵	0~25 ml	± 0.1 ml
温度	T型热电偶	-270~400℃	± 0.5℃
电压	BP6020T	0~300 W	± 0.05%
电流	BP6020T	0~5 A	± 0.1%

Fig.2 Start-up characteristics of heat pipe for plate evaporator loop under different heating power

Fig.3 Start-up characteristics of heat pipe of plate evaporator loop under different filling rate conditions

Fig.4 Operation temperature of the loop heat pipe under various heating capacity

Fig.5 The stabilization condition under different filling ratios with various heating loads

Fig.6 Heat transfer characteristics of the loop heat pipe under different liquid filling rates condition

Fig.7 Relationship between thermal resistance and thermal load under different liquid filling rates

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