Numerical Investigation of MHD Heat Transfer in a Nanofluid Trapezoidal Cavity with Embedded Square Heat Sources

This study presents a comprehensive numerical investigation of magnetohydrodynamic (MHD) heat transfer within a trapezoidal cavity filled with a Cu–H2O nanofluid and containing two symmetrically embedded square heat sources. The effects of varying nanoparticle volume fractions (ϕ = 0.01, 0.02, and 0.03), Hartmann number (Ha = 0, 30), and Rayleigh number (Ra = 103 - 106) were analyzed to assess flow and thermal behaviors. The governing equations for incompressible, laminar flow and heat transfer were solved using COMSOL Multiphysics under steady-state conditions. Velocity and temperature contours reveal that increasing Ra enhances convective heat transfer, with pronounced thermal gradients and stronger circulation cells. Conversely, higher Ha values suppress fluid motion due to the Lorentz force, reducing convective effects and promoting conduction. At higher nanoparticle concentrations, thermal conductivity improves, intensifying heat transfer despite magnetic damping. The sinusoidal upper wall and trapezoidal cavity shape introduce complex flow interactions, especially near the embedded heat sources. Velocity profiles show peak flow intensities around the heated regions, while temperature fields confirm improved thermal distribution with increasing ϕ. Results highlight the significant role of magnetization and nanoparticle concentration in optimizing heat transfer in nanofluid systems. The findings offer valuable insights for designing thermal systems such as electronic cooling devices and energy storage systems, where enhanced convective performance in confined geometries is essential.