Numerical analysis of magnetohydrodynamic mixed convection for electronic thermal management: Coupling nano-encapsulated PCM with double-diffusive transport

This study numerically investigates the hydrothermal performance and entropy generation in a trapezoidal cavity filled with nano-encapsulated phase change material (NEPCM)-water mixture for electronic cooling under magnetohydrodynamic (MHD) and double-diffusive mixed convection. The governing equations were solved using the Galerkin finite element method. The novelty lies in exploring the coupled effects of MHD suppression and NEPCM thermal enhancement on integrated circuit (IC) cooling performance. Key parameters investigated include Reynolds number ( R e = 10 − 100 ), Richardson number ( R i = 0.1 − 7 ), Lewis number ( L e = 0.1 − 10 ), Hartmann number ( H a = 5 − 80 ), NEPCM volume fraction ( ϕ = 0.015 − 0.035 ), Stefan number ( S t e = 0.1 − 0.8 ), and fusion temperature ( θ f = 0.1 − 0.9 ). Results reveal that heat transfer enhancement reaches 192.77% at R e = 100 when R i increases from 0.1 to 7, with L e = 0.5 , N z = 2 , S t e = 0.1 , θ f = 0.5 , ϕ = 0.01 , and H a = 10 held constant), while NEPCM concentration increases the average Nusselt number ( N u a v ) by 33.77% when ϕ increases from 0.015 to 0.035 at R e = 50 , R i = 1 , L e = 0.5 , N z = 2 , S t e = 0.1 , θ _ f = 0.5 , a n d H a = 10 . However, magnetic field strength suppresses convection, reducing heat transfer. Mass transfer characteristics show strong Lewis number sensitivity but remain insensitive to phase change parameters. Entropy generation decreases with both NEPCM concentration and magnetic field strength. These findings provide optimization guidelines for designing energy-efficient electronic cooling systems utilizing NEPCM under magnetic field influence.