大直径高温热管在高热流密度下的性能实验研究  

Performance of large-diameter high-temperature sodium heat pipes at high heat flux

作　　者：白玉潭 刘家驹 张平[1] Yutan Bai;Jiaju Liu;Ping Zhang(School of Mechanical and Electrical Engineering,Guilin University of Electronic Technology,Guilin 541004,China)

机构地区：[1]桂林电子科技大学机电工程学院,桂林541004

出　　处：《科学通报》2023年第2期271-281,共11页Chinese Science Bulletin

基　　金：国家自然科学基金(52076048)资助。

摘　　要：高温热管的启动性能和均温性能与其总传热量通常是两个相对立的性能表现,而大直径的高温热管由于其很高的总传热量,在高热流密度条件下具有广泛的发展潜力和应用前景.本文制备了大直径高温热管,研究了其在高热流密度条件下的启动性能、轴向和径向均温性以及等效热阻.结果表明:在高热流密度和自然对流条件下,高温热管能够在-45°~90°范围内正常启动,具有一定的抗重力特性.根据努森数得出蒸气流转变温度,并以此为基础将大直径高温热管启动过程划分为6个阶段,启动期间温度曲线形成4个温度“阶梯”.这6个阶段和4个温度“阶梯”在实验中均被观测到,由此归纳出了大直径高温热管典型的6阶段升温曲线.此外,该高温热管在高热流密度下表现出优异的启动性、均温性和低热阻特性,最小等效热阻可以达到0.02 K/W.实验发现,大直径高温热管径向温差最大可达50℃,但提高热流密度能够改善其径向均温性.High temperature heat pipes can achieve high-efficiency heat transfer from the heating side to the condensing side at temperatures up to 1000°C and above the order of 1 kW/cm^(2), which are high-efficiency passive heat transfer elements under high temperature conditions and widely used in aerospace, nuclear industry, solar power generation, and other fields.Under complex operating conditions, the start-up characteristics and temperature homogeneity are critical indicators for evaluating the heat transfer performance of high temperature heat pipes. According to previous research, the total heat transfer of high temperature heat pipes increases with the increase of their diameters. However, the start-up characteristics and temperature homogeneity performance of heat pipes are opposite to their total heat transfer performance. In an environment with high heat flux density, high temperature heat pipes with conventional diameters are disabled to quickly evacuate the heat owing to the size of the structure. Large-diameter high temperature heat pipes have the advantage of high total heat transfer, which gives them vast development potential and application prospects in the thermal evacuation environment with high heat flux density. Therefore, we use large-diameter sodium heat pipes to investigate their performance under high heat flux density conditions. In this paper, we compared the start-up performance of high temperature heat pipes with different inclination angles and heating heat flow densities, and analyzed their axial and radial temperature homogeneity and equivalent thermal resistance. The results show that the high temperature heat pipe can generally start at –45° to 90° under high heat flow density and natural convection. It also has a specific resistance to gravity.According to the Nusson number, the vapor state is divided into the free molecular flow, the molecular transition flow, and the continuous molecular flow. Based on this theory, the start-up process of large-diameter high temperature heat pipe

关 键 词：高温热管 高热流密度 大直径 启动性能 均温性 

分 类 号：TK172.4[动力工程及工程热物理—热能工程]