NUMERICAL ANALYSIS OF ENTROPY CONTROLLED NATURAL CONVECTION IN FIN ATTACHED SQUARE ENCLOSURE
The present work is intended to study the variation of heat transfer and entropy generation in a natural convective square enclosure consists of two different fins rectangular and tapered geometries. The finite volume method based commercial software FLUENT is used to perform simulations. After successful validation of results against published results for natural convection in a cavity filled with air, simulations are carried out on rectangular fin embedded square enclosure filled with air for analyzing the effect various parameters on heat transfer as well as local entropy generation. Further, simulations are extended for taper fin. The position of fin is varied for various fin lengths along vertical direction in the enclosure to predict the optimum performance interms of average Nusselt number, heat transfer and entropy generation. The two dimensional, steady and laminar convective heat transfer conditions are considered for present analysis neglecting effect of thermal contact resistance between the wall and fin. In the present analysis the performance is measured in terms of average Nusselt number considering the Rayleigh number ranging from 103 to 106 for heat transfer parameter and dimensionless fin length from 0.4L to 0.8L, dimensionless fin position from 0.1L to 0.9L considered as geometric parameters.
The effect of Rayleigh number (Ra), fin position (H), fin length (Ld) on Nusselt number (Nu) for two fin geometries has been plotted. The enhancement of heat transfer in the case of tapered fin observed to be 32.25% which is better than cavity with rectangular fin and no fin cases. The value of maximum heat transfer for both cases is observed at low Rayleigh number Ra=103 and fin length Ld=0.8L at H=0.5L fin position.