Thermal Performance Evaluation of Heat-Generating Fluid in MHD-Influenced Wavy Trapezoidal Cavity with Heated Solid Square Block

This research presents a comprehensive thermal performance evaluation of a heat-generating fluid within a magnetohydrodynamic (MHD)-influenced wavy trapezoidal cavity containing a centrally positioned heated solid square block. The study systematically explores the effects of varying Rayleigh number (Ra), Hartmann number (Ha), and internal heat generation coefficient (Δ) on natural convection, flow structure, and thermal transport inside the cavity. Numerical simulations were carried out for a wide range of parameters: Ra (10³–10⁵), Ha (0, 10, 20), and Δ (0, 5, 10). Streamline analysis demonstrates that as Δ increases, the flow circulation becomes more vigorous and buoyancy-driven, resulting in intensified and asymmetric vortex formations around the heated block. However, increasing Ha exerts a damping influence, suppressing fluid motion and limiting the strength of recirculating vortices. Isotherm analysis reveals that heat generation causes tighter and more distorted temperature contours, indicating higher thermal gradients and stronger convective effects. In contrast, a higher Hartmann number smooths out the isotherms, indicating reduced thermal mixing and dominant conduction. The average Nusselt number decreases consistently with increasing Ha and Δ, illustrating that magnetic suppression and internal heat generation reduce the wall heat transfer rate. The highest thermal performance is observed for low Ha and Δ, while the lowest is found at high Ha and Δ combinations. The study concludes that while internal heat generation enhances internal fluid circulation, it lowers overall thermal efficiency under stronger magnetic field conditions. These findings offer insights into optimizing thermal management systems where internal heating and electromagnetic fields are present.