ENTROPY ANALYSIS FOR MHD FLOW OF CASSON FLUID IN AN ANNULAR DUCT PARTIALLY FILLED WITH POROUS MEDIUM WITH ASYMMETRIC CONVECTIVE COOLING: AN EXACT SOLUTION

The present study intends to analyze entropy production in MHD flow of Casson fluid in an annulus filled partially filled with a porous material. The outer and inner walls of the annulus are cooling convectively in an asymmetric manner. Heat transfer effects like radiation and heat source are incorporated. The problem is solved analytically, and the expressions for velocity and temperature distribution are obtained in terms of Bessel functions. Using these expressions entropy production is computed. Furthermore, the problem is solved numerically also, using the fifth-order exactness program (bvp5c) along with the shooting approach on MATLAB. A good match is observed between the numerical and exact solutions. The findings are also compared to the existing literature and found in agreement. The effects of numerous relevant parameters on temperature distribution, velocity distribution, and entropy production are presented graphically and discussed. It is concluded that the Grashof number and permeability of porous medium rises the pace of the flow, while the Reynolds number and Hartmann number reduce it. The impacts of the thermal Biot number (Bi1) and heat generation parameter are also found to upsurge the temperature field, while opposite effect is observed due to thermal Biot number (Bi2), radiation and thermal conductivity ratio (M). The researchers further concluded that the Biot number (Bi2), Reynolds number, and temperature difference parameter reduce the entropy profile, while scenario reversed due to the radiation parameter, Brinkman number, and heat generation parameter. The results of the study may find applications of practical importance in engineering fields such as designing heat exchangers, cooling processes, improving energy storage systems, etc.