Minimization of entropy generation in natural convection using optimum isothermal heaters: CFD analysis

Designing thermal systems with minimum entropy generation and enhanced thermal performance is essential in engineering applications. An enclosed thermal system's performance can be optimised by the investigation of pertinent parameters on entropy generation. The present work focuses on the effect of heater location, Rayleigh number, and constant temperature boundary conditions on entropy generation in an air-filled square enclosure. A numerical model is developed by validating the available literature and analysing entropy generation due to heat transfer and fluid friction. The square enclosure is embedded with two isothermal heaters as a source of natural convection with equal strength and length. The total entropy generation due to heat transfer and fluid friction is estimated by changing the heater location within the enclosure at various Rayleigh numbers (10(3)-10(7)). The heat transfer and entropy generation about natural convection are presented in Nusselt number, Bejan number, isotherms, streamlines, and uniquely numbered entropy generation lines. At heater position L-d = 0.3L, heat transfer is enhanced for all Rayleigh numbers, despite recorded higher entropy. It is perceived that entropy generation due to both fluid friction and heat transfer is sensitive to the position of heaters and Rayleigh numbers. Finally, the optimal location of heaters is studied with the help of Bejan numbers.