Investigation on characteristic of mass-flow in loop heat pipe with different working fluids under different load powers

doi:10.16085/j.issn.1000-6613.2019-1776

Abstract

Abstract:

The transient mass transfer of loop heat pipes (LHP) was studied to improve the simulation precision and enrich the experimental research methods for LHP. The mass flow rates of three LHPs with acetone, ethanol, and propylene as working fluids under different heating powers were investigated using a high-precision mass flowmeter. Results showed that at the start-up stage, when the heat load was 10W, the propylene LHP started up faster than that of the acetone and the temperature stability of two LHPs appeared lingeringly than the stability of mass flow; at steady state, with the increase of heat load, the average mass flow of LHP with different working fluids increased linearly, while the transient mass flow fluctuated continuously, and the fluctuation amplitudes decreased initially and then increased. The fluctuation amplitude of mass flow was jointly affected by the compressibility of vapor working medium and the heat applied on the capillary core. Through spectrum analysis, it was found that the fluctuation of liquid mass flow was also affected by the two-phase area of condenser. Under high heat loads, the heat load on the capillary core played a leading role, and the exacerbated fluctuation of vapor mass flow with large periodic variation was observed. The fluctuation frequency accelerated under a higher heat loads.

Key words: loop heat pipe, working fluid, heat load, mass flow rate, evaporation, flow, mass transfer

摘要：

为了进一步提高回路热管仿真精度并丰富回路热管实验研究方法，本文对回路热管瞬态传质进行实验研究。使用高精度质量流量计分别对以丙酮、乙醇、丙烯为工质的回路热管进行不同负载功率下的质量流量测量研究。结果表明：启动阶段，热负载10W时，丙烯回路比丙酮回路热管启动快，且两者的温度稳定均滞后于质量流量；稳定阶段，随着热负载功率增大，不同工质的回路热管的平均质量流量均线性增长，而瞬态质量流量则持续波动，其质量流量波动幅度均呈现先减小后增大的趋势。质量流量波动幅度会受到气体工质的可压缩性与作用在毛细芯内部上的热量的共同影响。通过频谱分析发现，液相质量流量波动还会受到冷凝器两相区的影响。高热负载下，作用在毛细芯内部上的热量占主导地位，质量流量波动加剧，同时出现周期性大幅波动，且其波动频率随着热负载增大而增大。

关键词: 回路热管, 工质, 热负载, 质量流量, 蒸发, 流动, 传质

CLC Number:

TK172.4

Chao LIU, Rongjian XIE, Deping DONG. Investigation on characteristic of mass-flow in loop heat pipe with different working fluids under different load powers[J]. Chemical Industry and Engineering Progress, 2020, 39(8): 2980-2988.

刘超, 谢荣建, 董德平. 不同工质回路热管负载功率变化下的质量流量特性[J]. 化工进展, 2020, 39(8): 2980-2988.

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