梯度润湿性表面增强超薄环路热管的研究

RESEARCH ON SURFACE WETTABILITY GRADIENT ENHANCED ULTRA-THIN LOOP HEAT PIPE

董佳佳

11849004

硕士

机械工程领域工程

祝渊

2020-05-28

2020-07-20

哈尔滨工业大学

深圳

电子行业正在不断地向前快速发展，根据市场需求，电子芯片也正在不断向着小型化、微型化发展，芯片的小型化、高性能化及高集成度导致了芯片的热流密度不断增加，与此同时电子设备的散热空间却不断变小，而工作温度是影响着芯片性能的重要因素，所以如何有效进行有限空间内的热管理是急需解决的关键问题。环路热管为相变式传热，由于其传热距离长、受重力影响小、热二极管、传热能力高等优点被认为是解决上述情况散热的有效方式。随着环路热管的缩小，其传热性能也受到了诸多方面的限制，其中重要限制之一为环路热管内部循环动力的限制，即环路热管内部吸液芯所提供的毛细吸力可能会出现不足的情况，为了增加环路热管中工作介质循环的动力，本文对环路热管内壁进行了表面处理，使得环路热管与固体表面润湿性相结合。将固体材料梯度润湿表面对液滴具有驱动性应用于环路热管，在气体通路中进行的疏水表面处理可以减小气体流动的热阻，在液体通路中进行的亲水梯度处理可以为液体提供驱动力，从而为环路热管内部循环增加动力。本文基于以上研究目的，对制备铜基梯度润湿性表面进行了研究。对不同反应下，铜基表面润湿性与反应时间进行了探究，最终结合提拉法及推注法制备出了对液滴有驱动作用的铜基梯度润湿表面。对环路热管的设计与焊接进行了研究。本文将环路热管设计成为了板状结构并将吸液芯设计为耙状结构。本文选择了泡沫铜作为制备吸液芯的材料，并对所制得的吸液芯进行了性能表征及测试，经过亲水处理后的吸液芯的毛细吸力值为2621.8 N/m^2；吸液芯制备完毕后，本文对铜的焊接进行了研究，从而选择了软钎焊对环路热管进行了焊接。本文提出并使用了一种全新的除气充液方式，此种除气充液方式可以对充液的量进行精确控制，且只需一次组装即可完成环路热管的除气及充液。环路热管经除气、充液及密封后，对环路热管进行了性能测试，主要对环路热管各点温度进行了采集、处理、分析，最终分析得出本文所制备的环路热管启动温度在43℃左右，经过表面处理的环路热管对比未经表面处理的环路热管性能有所提升：在加热功率为3.6 W时，其热阻减小了13.2%，经表面处理的环路热管的具有更好的均温性。

The electronics industry is developing rapidly. According to market demand, electronic chips are also developing towards miniaturization. The miniaturization, high performance and high integration of chips have led to the increasing heat flux density of chips. At the same time, the heat dissipation space of electronic equipment is getting smaller and smaller, the operating temperature is an important factor that affects the performance of the chip, so how to effectively carry out thermal management in a limited space is a key problem that needs to be solved urgently. The loop heat pipe is a phase-change heat transfer, Due to its advantages of long heat transfer distance, small influence by gravity, thermal diode, and high heat transfer capacity, it is considered to be an effective way to solve the above situation.As the loop heat pipe shrinks, its heat transfer performance is also limited by many aspects. One of the important limitations is the circulating power inside the loop heat pipe, that is, the capillary suction provided by the wick inside the loop heat pipe may be shortage, in order to increase the power of the working circulation in the loop heat pipe. We introduce wettability gradient in the design of loop heat pipe to provide an extra driving force for circulating the working fluid. The hydrophobic surface treatment in the gas path can reduce the thermal resistance of the gas flow, and the hydrophilic gradient treatment in the liquid path can provide the liquid driving force to increase the power for the internal circulation of the loop heat pipe.Based on the above research purposes, this paper studied the preparation of copper-based gradient wettability surface. Under different reactions, the wettability and reaction time of the copper-based surface were explored. Finally, the copper-based gradient wettability surface with driving effect on the droplets was prepared by combining the above reaction and lift method or injection method.The design and welding of the loop heat pipe were studied. In this paper, the loop heat pipe is designed as a plate structure and the wick is designed as a rake structure. In this paper, copper foam is selected as the material for preparing the wick, and the performance of the prepared wick is characterized and tested. The capillary suction value of the wick after hydrophilic treatment is 2621.8 N/m^2. After the preparation of the wick is completed, the copper welding is studied in this paper, and the soldering is selected to weld the loop heat pipe.A new degassing and filling method is proposed and used in this paper. This kind of degassing and filling method can accurately control the amount of filling, and only one assembly can complete the degassing and filling of the loop heat pipe. After the degassing, filling and sealing of the loop heat pipe, the performance test of the loop heat pipe was carried out. The temperature of each point of the loop heat pipe was collected, processed and analyzed. Finally, the loop heat pipe prepared in this paper was started when the temperature is around 43℃, the performance of the surface-treated loop heat pipe is improved compared with the surface-treated loop heat pipe; when the heating power is 3.6 W, the thermal resistance is reduced by 13.2%, and the surface-treated loop heat pipe has better temperature uniformity.

板状环路热管 梯度润湿表面 接触角 软钎焊 除气充液装置 传热特性

plate loop heat pipe gradient wetting surface contact angle soft soldering degassing and filling device the heat transfer characteristics

中文

联合培养

南方科技大学

董佳佳. 梯度润湿性表面增强超薄环路热管的研究[D]. 深圳. 哈尔滨工业大学,2020.