基于(火积)理论的“+”形高导热构形通道实验研究

基于构形理论和■理论,对"+"形高导热通道的方形构造体开展导热实验研究,并对不同优化目标和不同高导热通道布置形式下的构造体导热性能进行比较.结果表明:对于"+"形高导热通道的方形构造体,实验和数值计算所得到的构造体最高温度点均位于"+"形高导热通道两分支之间,实验和数值计算所得到的构造体平均温差和■耗散率的误差均在可接受范围内,这从定性和定量的角度证明了导热构形优化结果的正确性.与"H"形高导热通道的方形构造体相比,构造体内高导热通道采用一级"+"形布置使得其导热■耗散率得到降低.■耗散率最小的一级"+"形高导热通道构造体最优构形与最大温差最小的构造体最优构形相比,前者的导热■耗散率降低了5.98%,但最大温差提高了3.57%.最大温差最小目标有助于提高构造体的热安全性,■耗散率最小目标有助于提高构造体的整体导热性能.在保证热安全性能的前提下,实际微电子器件设计中可采用■耗散率最小的构造体最优构形以提高其整体导热性能.

Experimental study on “+” shaped high conductivity constructal channels based on entransy theory

Based on constructal theory and entransy theory, an experimental study on “+” shaped high conductivity channels in a square body is carried out. Heat conduction performance comparisons of the bodies based on different optimization objectives and different layouts of the high conductivity channels are performed. In the experiment, the materials of the square body and high conductivity channel are epoxy resin and brass, respectively; the brass channel is embedded in the square body. Two square heating boards, closed at the upper and lower sides of the square body, are used to uniformly heat itself. The internal heat generation of the square body is approximately simulated by this method. The square body is placed in a thermal insulation box to reduce the heat dissipation caused by heat convection. The heat generated by the heating boards is absorbed by the outside refrigerator device. A measurement window is set at the front side of the thermal insulation box. The temperature field of the square body is measured by the infrared thermal imager. The peak temperature, average temperature difference, and entransy dissipation rate of the body can be calculated by the measured results, respectively. Experimental results are compared to those obtained by numerical calculations; the results show that for the “+” shaped high conductivity channels in a square body, the maximum temperatures are located between the two branches of the “+” shaped high conductivity channels for both experimental result and numerical calculation. The errors in the average temperature and entransy dissipation rate of the body based on the experimental result and numerical calculations are within the acceptable range. The two results verify their validity of the heat conduction constructal optimization. Compared the square body with “H” shaped high conductivity channel, the entransy dissipation rate of the body caused by heat conduction is reduced by adopting the first order “+” shaped high conductivity channel. Compared with the optimal constructs of the first order “+” shaped high conductivity channels based on the minimizations of entransy dissipation rate and maximum temperature difference, the entransy dissipation rate caused by heat conduction of the former construct is reduced by 5.98%, but the maximum temperature difference is increased by 3.57%. The aim of maximum temperature difference minimization helps to improve the thermal safety of a body, while that of the entransy dissipation rate helps to improve the global heat conduction performance of a body. When the thermal safety is permitted, the optimal construct based on entransy dissipation rate minimization can be adopted in the design of practical electronic device to improve its global heat conduction performance.