非均匀矩形产热体对流传热构形设计

Constructal Design of a Non-uniform Heat Generating Body Cooled by Convection

针对电子器件非均匀发热问题,建立考虑流体流动和传热的三维非均匀矩形产热体模型,以综合考虑(火积)耗散率和耗功率的复合函数为优化目标,基于有限元方法对冷却流道直径和宽高比进行优化,得到矩形单元体在不同产热分布条件下的最优构形。结果表明:综合考虑传热性能和压降损失的复合函数对无量纲流道直径存在极值;当单元体个数从10增加到30时,复合函数的最小值减小了 16.7%;以双自由度对矩形非均匀产热体开展构形设计可进一步提升对流传热的综合性能;提升矩形产热体内部产热的均匀性有益于降低传热过程中的(火积)耗散率,设计人员以综合衡量(火积)耗散率和耗功率的复合函数为优化目标时应尽量将发热元件均匀布置在矩形产热体内。

Regarding the non-uniform heat generating phenomenon of real electronic devices,a three-dimensional non-uniform rectangular heat generating model simultaneously revealing fluid flow and heat transfer characteristics is established.Taking a complex function composed of the entransy dissipation rate and pump power as the performance indicator,the diameter of cooling channels and aspect ratio of the construct are optimized by utilizing the finite element method.On this basis,the optimal constructs of rectangular element are obtained in cases of various heat generating premises.In this paper,the obtained results show that the complex function features an extreme value for the dimensionless cooling channel diameter.The minimum value of the complex function slumps by16.7%as the number of elements increases from 10 to 30.Inspired by constructal law,the overall thermo-fluid performance can be elevated as releasing the constant aspect ratio constraint of the element.Increasing the uniformity of internal heat generation can attribute to reducing the entransy dissipation rate.Oriented to industrial applications,heat generating devices should be equidistantly placed over the electronic components as driven by the complex function composed of the entransy dissipation rate and pump power.