Effect of combined natural convection and non-gray gas radiation on entropy generation in a circular enclosure with partial heating

Abstract

This article reports a numerical analysis of combined natural convection and non-gray gas radiation within a cylindrical enclosure, isothermally heated and cooled on various arc lengths of the sidewall. Three active zone locations are studied in this article. The first heating section extends quarter the perimeter of the cavity, the second spreads across one-half of the cylinder, and the third one is made of three-quarters of the sidewall. The participating media are considered as emissive, absorbent, and non-scattering. The radiative transfer equation is resolved using the Ray-Tracing method associated to the Statistical Narrow Band–correlated K model. The effect of heater size and its location on heat transfer, fluid flow, and entropy generation are presented and discussed in this work. The results show that the optimum heater size is obtained for three-quarters heated enclosure. It was also found that choosing a heat source centered at the top of the enclosure provides the best heat transfer performance.