Effect of Wick Characteristics on the Thermal Performance of the Miniature Loop Heat Pipe
Effect of Wick Characteristics on the Thermal Performance of the Miniature Loop Heat Pipe
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DOI：
10.1115/1.3109994
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发表时间：
2009-08-01
影响因子：
--
通讯作者：
Mochizuki, Masataka
中科院分区：
文献类型：
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作者：
Singh, Randeep;Akbarzadeh, Aliakbar;Mochizuki, Masataka
基于微型回路热管（LHP）的两相传热装置由于其高热流管理能力和以最小的温度损失进行长距离传热，可以为紧凑型电子设备提供非常有前途的冷却解决方案。本文讨论了吸液芯特性对微型液体热泵传热特性的影响。小型模型的LHP与盘形蒸发器，10 mm厚和30 mm盘直径，设计使用铜密封容器和水作为工作流体，这是最可接受的组合在电子冷却应用。在调查中，芯结构具有不同的物理性能，包括导热性，孔隙半径，孔隙率和渗透性和不同的结构拓扑结构，包括单孔或双孔蒸发面被使用。通过实验观察到，铜芯能够提供比镍芯上级的热性能，特别是对于低至中等的热负荷，这是由于它们的低导热电阻。使用单孔铜芯，最大蒸发器传热系数（h（ev））为26，270 W/m（2）K，蒸发器热阻（R-ev）为0.06-0.10 ° C/W。对于单孔镍芯，相应的值为20，700 W/m（2）K（h（ev））和0.08-0.21 ℃/W（R-ev）。具有较小孔径、高孔隙率和高渗透率的毛细管结构由于足够的毛细管泵送能力、从蒸发器到补偿室的低热泄漏和用于热交换的较大表面积与体积比而显示出更好的传热特性。除此之外，双孔铜吸液芯结构显示出比单孔铜吸液芯高得多的83，787 W/m（2）K的传热系数，这是由于吸液芯壁界面处的蒸发传热得到改善以及液体和蒸气流动孔分离。本工作是能够分类的重要性，毛细性能的改善的热特性的微型环路热管。
Two phase heat transfer devices based on the miniature version of loop heat pipe (LHP) can provide very promising cooling solutions for the compact electronic devices due to their high heat flux management capability and long distance heat transfer with minimal temperature losses. This paper discusses the effect of the wick properties on the heat transfer characteristics of the miniature LHP. The miniature model of the LHP with disk-shaped evaporator, 10 mm thick and 30 mm disk diameter, was designed using copper containment vessel and water as the working fluid, which is the most acceptable combination in electronic cooling applications. In the investigation, wick structures with different physical properties including thermal conductivity, pore radius, porosity, and permeability and with different structural topology including monoporous or biporous evaporating face were used. It was experimentally observed that copper wicks are able to provide superior thermal performance than nickel wicks, particularly for low to moderate heat loads due to their low heat conducting resistance. With monoporous copper wick, maximum evaporator heat transfer coefficient (h(ev)) of 26,270 W/m(2) K and evaporator thermal resistance (R-ev) of 0.06-0.10 degrees C/W were achieved. For monoporous nickel wick, the corresponding values were 20,700 W/m(2) K for h(ev) and 0.08-0.21 degrees C/W for R-ev. Capillary structure with smaller pore size, high porosity, and high permeability showed better heat transfer characteristics due to sufficient capillary pumping capability, low heat leaks from evaporator to compensation chamber and larger surface area to volume ratio for heat exchange. In addition to this, biporous copper wick structure showed much higher heat transfer coefficient of 83,787 W/m(2) K than monoporous copper wick due to improved evaporative heat transfer at wick wall interface and separated liquid and vapor flow pores. The present work was able to classify the importance of the wick properties in the improvement of the thermal characteristics for miniature loop heat pipes.