Performance and optimum design analysis of longitudinal and pin fins with simultaneous heat and mass transfer: Unified and comparative investigations

In the present paper, the thermal analysis and optimization of longitudinal and pin fins of uniform thickness subject to fully wet, partially wet and fully dry surface conditions are carried out analytically, and also a comparative study is made between the longitudinal and pin fin for a wide range of design parameters. From the results, a significant effect on the temperature distribution in the fin and the fin efficiency with the variations in moist air psychometric conditions is noticed. For partially wet fins, the length of the wet–dry interface depends on the relative humidity RH, fin parameter Zd and geometry of the fin. From the results, it can also be highlighted that for the same thermo-geometric and psychometric parameters, a longitudinal fin gives higher efficiency than the corresponding pin fin irrespective of surface conditions. Next, a generalized scheme for optimization has been demonstrated in such a way that either heat transfer duty or fin volume can be taken as a constraint selected as per design requirement. From the optimization results, it can be pointed out that the optimum design of both the longitudinal and pin fin under the partially wet surface condition is only possible for a narrow range of relative humidity whereas for the fully wet surface, a wide range is noticed. Finally, design curves have been established for a wide range of thermo-psychometric parameters, which may be helpful to a designer for estimation of the optimum design variables of a fin with a minimum effort.