Numerical analysis of MHD combined convection for enhanced CPU cooling in NEPCM-filled a trapezoidal cavity

<p dir="ltr">This study investigates the cooling of a central processing unit (CPU) using a nano-encapsulated phase change material (NEPCM)-water mixture in a trapezoidal cavity with rotating cylinders and baffles. A numerical model based on the finite element method (FEM) is employed to solve the governing equations. The system is subjected to a sinusoidal temperature profile from the CPU and a constant magnetic field. Key parameters examined include Reynolds number (<i>Re</i>: 10–100), Richardson number (<i>Ri</i>: 0.1–10), Hartmann number (<i>Ha</i>: 5–80), NEPCM volume fraction (<i>ϕ</i>: 0.015–0.035), Lewis number (<i>Le</i>: 0.1–10), buoyancy ratio (<i>Nz</i>: 1–5), NEPCM fusion temperature (<i>θ</i> f : 0.1–0.9), and Stefan number (<i>Ste</i>: 0.1–0.9). Results show that increasing <i>Re</i> and <i>Ri </i>significantly enhances heat and mass transfer, with the average Nusselt number (<i>Nu</i>_<em>av</em>) increasing by up to 80.5 % and average Sherwood number (<i>Sh</i>_<em>av</em>) by up to 147.9 %. The magnetic field suppresses convection, reducing <i>Nu</i>_<em>av</em> by 12.7 % and <i>Sh</i>_<em>av</em> by 39.5 % as Ha increases. Increasing <i>ϕ</i> improves heat transfer (<i>Nu</i>_<em>av</em> up by 32.5 %) with minimal effect on mass transfer. Le strongly influences mass transfer, with <i>Sh</i>_<em>av</em> increasing by 284.6 % as Le increases. The NEPCM fusion temperature exhibits a non-monotonic effect on <i>Nu</i>_<em>av</em> , with an optimal value at <i>θ</i>_f = 0.5. In conclusion, the study reveals complex interactions between parameters, with <i>Re, Ri</i>, and <i>Le</i> having the most significant impacts on system performance. These findings provide valuable insights for optimizing CPU cooling systems using NEPCM-water mixtures and magnetohydrodynamic (MHD) effects.</p><h2>Other Information</h2><p dir="ltr">Published in: International Communications in Heat and Mass Transfer<br>License: <a href="http://creativecommons.org/licenses/by/4.0/" target="_blank">http://creativecommons.org/licenses/by/4.0/</a><br>See article on publisher's website: <a href="https://dx.doi.org/10.1016/j.icheatmasstransfer.2024.108343" target="_blank">https://dx.doi.org/10.1016/j.icheatmasstransfer.2024.108343</a></p>