Abstract In actual practical situations, the evaporator fins of refrigeration and air-conditioning apparatuses may operate under dry, fully wet or partially wet conditions. Thus in the present study, the optimum design of an array of constructal fork shaped fins operating under partially wet conditions has been determined by using a linear variation of the humidity ratio of saturated air with the corresponding fin surface temperature. The point of separation between the dry and wet portions may be located either in the stem or branch part of the fin and hence, two cases having different governing equations and boundary conditions are analysed in the current study. The optimisation study is done by maximising the total heat transfer rate of the fin array and un-finned surface and the constraints are imposed in such a way that fin material limitations, minimum fin gap requirements as well as space limitations in the radial direction are taken into account. For obtaining the optimum condition, a swarm based meta heuristic algorithm called Firefly algorithm has been employed. Arrays of fork-shaped fin having two and three numbers of branches are analysed in the present study and a comparative study is done with the rectangular fin array. For more compact evaporators, it would be more preferable to select the fin array that results in larger optimum heat transfer rate as well as that having a smaller total length of each fin. An important finding is that the array of fork–shaped fins with two branches give higher optimum heat transfer rate than that from the rectangular fin array in all the cases of different operating conditions. However, no advantage with respect to either higher optimum heat transfer rate or smaller fin length is obtained when the number of branches of fork shaped fins is increased from two to three.

中文翻译：

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叉形结构翅片阵列设计是干燥、部分潮湿和完全潮湿条件下传热和传质增强的更好替代方案

摘要 在实际应用中，制冷和空调设备的蒸发器翅片可以在干燥、全湿或半湿条件下运行。因此，在本研究中，通过使用饱和空气湿度比与相应翅片表面温度的线性变化来确定在部分潮湿条件下运行的构造叉形翅片阵列的最佳设计。干湿部分之间的分离点可能位于翅片的茎部或分支部分，因此，在当前的研究中分析了具有不同控制方程和边界条件的两种情况。优化研究是通过最大化翅片阵列和非翅片表面的总传热率来完成的，并以翅片材料限制、最小翅片间隙要求以及径向空间限制的方式施加约束考虑到。为了获得最佳条件，采用了称为萤火虫算法的基于群的元启发式算法。本研究分析了具有两个和三个分支的叉形鳍阵列，并与矩形鳍阵列进行了比较研究。对于更紧凑的蒸发器，更优选选择导致更大的最佳传热率以及每个翅片的总长度更小的翅片阵列。一个重要的发现是，在所有不同操作条件的情况下，具有两个分支的叉形翅片阵列比矩形翅片阵列提供更高的最佳传热率。然而，当叉形翅片的分支数量从两个增加到三个时，没有获得更高的最佳传热率或更小的翅片长度方面的优势。