Double diffusive mixed convection and entropy generation analysis of NEPCM-water mixture in a π-shaped cavity
Ahmed M. Hassan, Mohammed Azeez Alomari, Abdellatif M. Sadeq, Faris Alqurashi, Mujtaba A. Flayyih
Abstract
Thermal systems utilizing nano-encapsulated phase change materials (NEPCMs) in complex geometries offer promising solutions for efficient energy storage and management under electromagnetic control. This study aims to investigate double-diffusive mixed convection and entropy generation in a π-shaped cavity with wavy lid containing NEPCM-water mixture subjected to a transverse magnetic field. The mathematical model employs the Boussinesq approximation for density variations while disregarding viscous dissipation and chemical interactions. Governing equations are solved using finite element analysis with Galerkin's method across wide parametric ranges of Reynolds (25–100), Richardson (0.1–10), Lewis (1–5), Stefan (0.1–0.9) numbers, fusion temperature (0.1–0.9), NEPCM concentration (0.01–0.04), and Hartmann number (0–80). Results demonstrate that Reynolds and Richardson numbers significantly enhance heat and mass transfer (up to 204 % increase in Nusselt number), while magnetic fields substantially suppress convective transport (60.5 % reduction in Nusselt number). NEPCM concentration improves thermal performance by 39.3 % with minimal effect on mass transfer. Entropy generation analysis reveals that thermal irreversibilities dominate, with both magnetic field strength and NEPCM concentration reducing system irreversibilities. These findings provide critical insights for optimizing thermal energy storage systems with electromagnetic regulation in applications ranging from solar collectors to electronic cooling solutions.