Numerical Analysis of Heat Transfer and Entropy Generation for Natural Convection in a Quadrantal Cavity with Non-uniform Heating at the Bottom Wall

Abstract

We analyze the characteristics of thermal transport along with entropy generation in a quadrantal cavity, which is non-uniformly heated along the bottom boundary wall, the upright wall maintained at a constant temperature, while the arched wall being maintained adiabatic. The numerical experimentation is carried out for Rayleigh number (Ra) in the range of 103–106. The results are depicted through the distribution of streamline contour and isotherm contour within the enclosure, local heat transfer rate (Nu) along the bottom boundary wall and cold upright wall, and also average heat transfer rate. Further, the irreversibility characteristics are also presented in the form of distribution of local entropy generation due to heat transfer attributes and fluid friction attributes within the enclosure and the average Bejan number. The results reveal that Nu at the bottom wall follows a sinusoidal variation and primarily at lesser values of Ra chosen for the study, the means of heat transfer is conduction, while at higher Ra the mechanism is essentially convection. The study also enlightens the fact that at low Ra (=103), the irreversibility is essentially owing to heat transfer irreversibility (IHT) while at larger values of Ra (=105 as well 106) fluid friction irreversibility (IFF) is predominant over IHT. For an intermediate range of Ra, both IHT and IFF are comparable.