Natural convection and surface radiation heat transfer in a cavity with vertically oriented fins

Abstract

In this paper, the finite volume method is combined with the discrete ordinate method to study the natural convection coupled to surface radiation in a cooled square finned cavity. The fin array under consideration is made of N thin fins arranged in a single horizontal row. For better heat transfer performances, all these fins are oriented vertically inside the cavity and heated isothermally at 299K≤TH≤341K. The cavity is filled with air (Pr=0.71) and cooled by the side vertical walls maintained at a cold temperature TC=293K. The study investigates the effect of the Rayleigh number ranging from 103 to 107, the fins number 1≤N≤15 and the emissivity 0≤ε≤1. The results are reported in terms of streamlines, isotherms and the local and the average convective and radiative Nusselt numbers. The numerical work is carried out using an in-house CFD code written in FORTRAN. The obtained results show a considerable effect of the surface radiation on the flow structure in the cavity and the maximum rate of heat transfer is reached when the fins number exceeds 9.