复合吸液芯超薄微热管制造工艺及传热性能分析

发布时间：2018-03-21 13:29

本文选题：超薄微热管　切入点：复合吸液芯　出处：《华南理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着微电子、光电子领域不断朝着高性能化和高集成度的方向发展,电子芯片的功耗日益增加,特别是在电子设备整体结构轻薄化、紧凑化的发展趋势下,电子元器件的散热问题日益凸显。微热管作为一种高效相变传热元件,已被广泛应用于解决众多领域的热问题。但要在结构紧凑的电子设备上利用微热管散热,,必须开发出厚度更薄、体积更小且传热性能良好的超薄微热管。吸液芯结构是影响微热管传热性能最关键的因素之一,本文探究了三种适用于超薄微热管的复合吸液芯结构及其成形方法,包括了单弓形铜粉复合沟槽吸液芯、双弓形铜粉复合沟槽吸液芯和丝网复合沟槽吸液芯。制定了复合吸液芯超薄微热管的制造工艺路线,并确定了各工艺参数。本文实验制作了三种复合吸液芯结构的超薄微热管样品;利用扫描电子显微镜对样品的横截面、纵切面进行观测,观察复合吸液芯的复合烧结状态、挤压状态以及撕裂状态,探索压扁工艺对吸液芯结构最终成形所造成的影响,并结合传热性能实验结果分析吸液芯成形状态对传热性能的影响。本文基于微热管的传热极限理论推导各主要传热极限的计算方法,并通过代入复合吸液芯的结构参数以及工质的物性参数计算出超薄微热管主要传热极限的具体数值。发现三种复合吸液芯结构的超薄微热管主要受毛细极限的限制,55°C工作温度下,单弓形复合吸液芯结构样品的传热极限为12.5W,双弓形结构为15.4W,丝网结构为19.4W。本文搭建了实验平台,并对不同充液率下的三种复合吸液芯结构超薄微热管进行稳态性能和动态性能测试。先通过纵向对比,探索超薄微热管的最佳充液率;再横向对比不同吸液芯结构样品的传热性能,然后对比超薄微热管分别在正常工作下和烧干状态下的启动性能。通过红外热成像的手段探究超薄微热管的均温性能和吸液芯的毛细性能。实验表明:单弓形铜粉复合与双弓形铜粉复合结构的最佳充液率均为70%,丝网复合结构为80%,三种结构的传热极限功率分别为12 W、13 W和14 W,蒸发热阻呈现先减少后增加的趋势,而冷凝热阻相对稳定,基本维持在0.2 K/W以下。加热功率较低时,超薄微热管从启动到其稳定的时间大概为100秒;加热功率较高时,从启动到其温度出现烧干的时间大概为80秒。超薄微热管具有良好的均温性能,双弓形复合吸液芯的毛细性能最佳,丝网结构毛细性能最差。
[Abstract]:With the development of microelectronics and optoelectronics, the power consumption of electronic chips is increasing day by day, especially in the trend of thinning and compactness of the whole structure of electronic devices. The heat dissipation of electronic components is becoming more and more serious. As a kind of high efficiency phase change heat transfer element, microheat pipe, Has been widely used to solve thermal problems in many fields. But in order to use micro-heat pipes to dissipate heat on compact electronic devices, a thinner thickness must be developed. The structure of liquid absorbing core is one of the most important factors affecting the heat transfer performance of micro heat pipe. In this paper, three kinds of composite absorbent core structures and their forming methods suitable for ultra-thin micro heat pipe are studied. Including single bow copper powder composite groove suction core, double bow copper powder composite groove suction core and wire mesh composite groove suction core. In this paper, three kinds of ultra-thin micro-heat pipe samples with composite absorbent core structure are experimentally made, the cross section and longitudinal section of the sample are observed by scanning electron microscope, and the composite sintering state of the composite absorbent core is observed. To explore the effect of flattening process on the final forming of sucking core structure under extrusion and tearing conditions. Combined with the experimental results of heat transfer performance, the influence of the forming state of liquid absorbing core on the heat transfer performance is analyzed. Based on the heat transfer limit theory of micro-heat pipe, the calculation methods of each main heat transfer limit are deduced. The main heat transfer limit of ultra-thin micro-heat pipe is calculated by adding the structure parameters of composite absorbent core and the physical property parameter of working fluid. It is found that three kinds of ultra-thin micro-heat pipe with composite liquid absorbing core structure are mainly limited by capillary limit. At the operating temperature of 55 掳C, The heat transfer limit of the single arch composite absorbent core structure is 12.5 W, the double arch structure is 15.4W, and the wire mesh structure is 19.4W. the experimental platform is set up in this paper. The steady-state and dynamic properties of three kinds of ultra-thin micro-heat pipes with different liquid-absorbing core structures were tested. Firstly, the optimum liquid-filled rate of ultra-thin micro-heat pipes was explored by longitudinal comparison. Then the heat transfer performance of different absorbent core structure samples is compared laterally. Then, the starting performance of ultra-thin micro-heat pipe under normal operation and burning dry state was compared. The average temperature performance of ultra-thin micro-heat pipe and the capillary property of absorbent core were investigated by infrared thermal imaging. The results showed that: single bow copper. The optimum liquid-filled ratio of powder composite structure and double bow copper powder composite structure is both 70 and 80, and the heat transfer limit power of the three structures is 12 W / 13 W and 14 W respectively. The evaporation thermal resistance decreases first and then increases. However, the condensation thermal resistance is relatively stable, basically below 0.2 K / W. when the heating power is low, the time from starting to stabilizing the superthin micro-heat pipe is about 100 seconds, and when the heating power is high, The time from starting to drying at the temperature is about 80 seconds. The ultra-thin micro-heat pipe has good homogeneous temperature performance, the capillary property of double-arch composite absorbent core is the best, and the capillary property of wire mesh structure is the worst.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN605

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