Magneto‐Thermal Assessment of Ferrofluid Flow in Corrugated Porous Domain With Rotating Cylinder for Nuclear Systems

This research presents a novel approach by combining magnetohydrodynamic (MHD) flow with ohmic heating to investigate the conjugate mixed convective transport of ferrofluid in a discretely heated, smooth/wavy‐walled, square‐shaped porous compartment featuring a clockwise spinning cylindrical body positioned at various locations. It aims to maximize heat transfer efficiency and minimize entropy production. Numerical solutions are obtained using the Galerkin finite element weighted residual method to solve the two‐dimensional Navier–Stokes and heat energy equations. The parametric variations include Grashof number (10 6 ≤ Gr ≤ 10 8 ), Reynolds number (10 3 ≤ Re ≤ 10 4 ), and Hartmann number (31.62 ≤ Ha ≤ 100), dimensionless cylinder diameter (0.2 ≤ D ≤ 0.4), dimensionless cylinder vertical position (0.25 ≤ Y c ≤ 0.75), and dimensionless heater strip size (0.25 ≤ d h ≤ 0.75). The results are quantitatively expressed through the Nusselt number ( Nu ) of the hot wall, the mean fluid temperature, the overall entropy production, and the thermal performance criterion ( TPC ). Extensive analysis reveals that a transition from a conduction‐dominated region to a convection‐dominated region occurs at Gr = 3 × 10 7 , Re = 5477.23, and Ha = 74. Notably, the maximum values of Gr , Re , and Ha at d h = 0.25, D = 0.2, and Y c = 0.75 result in a 36.84% increase in the Nusselt number and a 64.89% reduction in TPC compared to those at d h = 0.75, thereby indicating optimal conditions. In contrast, the largest heater size yields the poorest performance, with a 26.93% drop in Nu and a 265.22% increase in TPC . Insights into the MHD mixed convective flow with a ferrofluid‐filled copper powder porous medium within a corrugated cavity at higher Grashof numbers contribute to a novel and deeper understanding of velocity and temperature distributions, heat transfer, and irreversibility, which mimics a nuclear reactor fuel channel and fluid‐chilling blankets.