Mixed convectionMHD non-Newtonian fluid with entropy generation

Sadia Asad^*

• Majmaah University, Al Majma'ah, Saudi Arabia

Abstract: This article investigates the magnetohydrodynamic (MHD) mixed convection flow of a viscoelastic fluid with entropy generation. Magnetohydrodynamic (MHD) mixed convection with entropy generation observes fluid flow in which both buoyancy-driven and externally driven convection occur instantaneously in the effect of a magnetic field. This study focuses on thermodynamic irreversibility, extracted as entropy generation, within the system. This topic is significant in various engineering applications such as nuclear reactors and electronic cooling devices. Research in this area usually devotes analytical simulations to exploring how key parameters such as the curvature parameter, viscoelastic, magnetic, mixed convection and Brinkman number impact heat transfer and entropy generation. The viscoelastic behavior of the fluid is modeled using the Walter-B constitutive equation. The flow is induced by a stretching cylindrical surface, and viscous dissipation is incorporated into the energy equation. Scientists and engineers worldwide have shown growing interest in the flow with entropy generation due to their unique properties. automotive engineering, metal spinning, heat transfer and storage systems, power generation, and renewable energy. Among these, heat transfer plays a crucial role in determining the efficiency and quality of the final product. Appropriate similarity modifications are introduced to reducethe governing "partial differential equations" (PDEs) into a system of "ordinary differential equations" (ODEs). Analytical solutions are obtained for the resulting nonlinear flow and thermal equations by using Homotopy analysis method. Values for the "skin friction" coefficient and "local Nusselt" numbers are processed and reviewed. The physical behavior of key parameters is illustrated through graphs and supported with tabulated data. A notable aspect of this study is the detailed analysis of entropy generation. Observations indicate that the curvature and mixed convection parameters enhance both the flow and heat transfer rates near the cylinder surface. The viscoelastic parameter similarly influences both the temperature and velocity profiles. Entropy generation increases significantly with higher values of the magnetic field strength and Brinkman number, while it decreases with higher values of the temperature ratio parameter and the Weissenberg number. These parameters can thus be effectively used to control the ¸entropy g˛eneration process.