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针对T形肋片,分别以基于(火积)耗散的当量热阻最小化和最大热阻最小化为目标,采用二维传热模型和有限元数值计算方法进行了构形优化,分析了全局参数a(综合了对流换热系数、肋片占据的总面积及其热导率)和肋片占比ф对当量热阻最小值和最大热阻最小值及其对应最优结构的影响,比较了两个目标下优化结果的异同.研究表明,两种优化目标下的最佳构形差异较大.以当量热阻最小为目标的优化比以最大热阻最小为目标的优化,能够显著降低肋片体内的传热平均温差.增大a和增大ф均可同时改善局部热点工作状况和整体平均传热性能.但是,增大a和增大ф对当量热阻最小和最大热阻最小两个目标的改善程度不一样;并且对任意一个目标,a和ф分别产生的影响也是不一样的.总体上,对应当量热阻最小值的T形肋比对应最大热阻最小值的T形肋要高得多;两种优化目标下,主干比分支的部分均要厚,但当量热阻最小化时两部分肋厚相对接近些;主干扁平、分支细长的T形肋有利于降低最大热阻.
Aiming at the T-shaped fins, the minimization of the equivalent thermal resistance and the minimization of the maximum thermal resistance based on the dissipation of heat are respectively considered. The two-dimensional heat transfer model and the finite element method are used to optimize the configuration. The effects of global parameters a (combining the convective heat transfer coefficient, the total area occupied by the fins and their thermal conductivity) and the ratio of fins ф to the minimum equivalent thermal resistance and the maximum thermal resistance and their corresponding optimal structures, The similarities and differences between the two optimization results are compared.The results show that the optimal configurations under the two optimization objectives are quite different.The optimization aimed at minimizing the equivalent thermal resistance is better than the one with the largest maximum thermal resistance, Reduce the heat transfer average temperature difference between the fins body.A and a increase ф can improve the working conditions of local hot spots and the overall average heat transfer performance.However, increasing a and increasing ф for the equivalent thermal resistance minimum and maximum thermal resistance The improvement of the minimum two goals is not the same; and for any one target, a and ф have different effects respectively.In general, the T-shaped rib corresponding to the minimum equivalent thermal resistance is smaller than the corresponding maximum thermal resistance T-shaped ribs are much higher; two optimization goals , They are thicker than the portion of the trunk branch, but two equivalents minimize thermal resistance is relatively close to some portion of the rib thickness; trunk flat, T-shaped branches of the elongated ribs help to reduce the maximum resistance.