Meshless numerical analysis of natural MHD convection in a zigzag trapezoidal cavity filled with nanofluid

Abstract

In this study, the magnetohydrodynamic natural convection heat transfer and flow behavior in a trapezoidal cavity with a partially heated zigzagged sidewall filled with nanofluid are numerically analyzed. A magnetic field is applied across the sidewall to investigate its impact on the thermal and hydrodynamic characteristics. The research explores the influence of critical parameters, including the Rayleigh number , nanoparticle volume fraction, number of zigzags on the sidewall, Hartmann number , and magnetic field inclination. The governing equations are solved using the RBF-FD meshless method , offering a flexible and accurate framework for modeling complex cavity geometries. The model’s accuracy is validated through comparisons with results reported in existing literature. The results indicate that increasing the number of zigzags improves flow uniformity but significantly reduces heat transfer due to increased flow resistance and the disruption of convection currents . This reduction is further intensified by the application of a magnetic field. For a nanofluid with a concentration of ϕ = 0 . 01 , the average Nusselt number decreases by 40% as the Hartmann number increases to 60. However, this reduction can be mitigated by adjusting the inclination angle γ , with an improvement of approximately 17% in the average Nusselt number observed when | γ | increases from 0° to 60°. Additionally, higher nanoparticle concentrations slightly enhance heat transfer. A comparison of Cu -water and Al 2 O 3 -water nanofluids reveals consistent thermal behavior between these two types of nanoparticles. These findings provide insights for optimizing nanofluid performance under magnetic field conditions and highlight the flexibility and accuracy of the meshless method for simulating magnetohydrodynamic heat transfer, particularly in unconventional cavity configurations.

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