Y形肋片[火积]耗散率最小构形优化

Constructal Entransy Dissipation Rate Minimization for Y-Shaped Assembly of Fins

结合(火积)耗散极值原理和构形理论,以基于(火积)耗散率的当量热阻最小化为目标,采用解析解法对Y形肋片进行了构形优化,分析了复合参数a(关于对流换热系数、肋片的包络面积及其热导率的简单函数)和肋片占比φ_1对Y形肋片优化的影响,并比较Y形和T形肋片的整体传热性能的优劣。结果表明,增大a和增大φ_1可降低肋片的无量纲当量热阻,改善其整体传热性能。总体积和肋片材料的体积都相同时,Y形肋片无量纲当量热阻要比T形肋片的无量纲当量热阻小很多。也就是说,Y形肋片优于T形肋片,更能提高系统的整体传热性能。

The constructal optimization for Y-shaped assembly of fins with the minimization of mean thermal resistance defined based on entransy dissipation rate is conducted by combining entransy dissipation extremum principle and constructal theory and adoping analytical method. The influences of the complex parameter, α, which is a simple function of the heat transfer coefficient of fin over all the exposed surfaces, the cross-sectional flow area of the assembly and its thermal conductivity, and the fraction of fin material, Ф1, on the heat conductance performance of the assembly of fins are analyzed, and the heat conductance performances between Y-shaped and T-shaped assemblies of fins are compared. The results show that the mean thermal resistance of the assembly is smaller as both a and Ф1 increase, and thus the heat conductance performance is improved. The mean thermal resistance of Y-shaped assembly is much smaller than that of T-shaped assembly when their total volume and their volume of fin materials are both equal. That is to say, Y-shaped assembly is better than T-shaped assembly and improves the heat conductance performance more.