Thermodynamic Analysis of Unsteady MHD Mixed Convection in a Radiating and Reacting Nanofluid Flow Through a Porous Medium Filled Inclined Cylindrical Annulus

This study presents a detailed thermodynamic investigation of unsteady hydromagnetic mixed convection flow of a nanofluid within a concentric inclined cylindrical annulus filled with a porous medium. The system experiences thermal radiation and surface cooling at the outer cylinder, while velocity slip is imposed at the inner cylinder boundary. The nanofluid model incorporates the effects of Brownian motion and thermophoresis to accurately describe microscale heat and mass transfer phenomena. An external magnetic field and the inclination of the annulus induce anisotropic behavior, significantly influencing both flow dynamics and thermal transport. The governing equations for momentum, energy, and nanoparticle concentration are formulated using the Boussinesq approximation and numerically solved via the shooting method coupled with the Runge-Kutta-Fehlberg (RKF45) integration technique, under appropriate boundary conditions. A comprehensive parametric analysis is conducted to evaluate the impacts of magnetic field strength, thermal radiation, slip coefficient, thermal and solutal Grashof numbers, thermophoretic and Brownian diffusion parameters, Biot number, Darcy and Forchheimer numbers, and inclination angle on velocity, temperature, and concentration fields. Additionally, variations in skin friction, Nusselt and Sherwood numbers, entropy generation rate, and Bejan number are examined. The results reveal the complex interdependence of thermal radiation, porous medium resistance, and nanoparticle transport mechanisms on entropy generation and thermal system performance. These findings provide critical guidance for the design and optimization of advanced thermal management systems utilizing nanofluids in porous geometries.