Energy storage and thermal management using a micropolar nano-encapsulated phase-change material in a vented cavity

This numerical investigation optimizes coupled heat and mass transfer in advanced thermal management systems. Thermosolutal mixed convection of a magnetized micropolar suspension containing nano-encapsulated phase change materials, NEPCMs, is analyzed in a vented cavity with an adiabatic cylindrical obstacle. The work uniquely integrates double-diffusive convection, specifically Soret and Dufour effects, thermal radiation via the Rosseland approximation, and magnetohydrodynamics within a single framework. The governing equations are solved using the finite element method to quantify the individual and combined impacts of key dimensionless parameters on transport characteristics. A systematic numerical simulation strategy is adopted by varying the cylinder radius from the absence of an obstacle ( R = 0 ) to larger configurations ( R = 0 . 15 –0.3), Richardson number ( R i = 1 –10), Reynolds number ( R e = 10 –200), nanoparticle volume fraction ( ϕ = 0 . 01 –0.05), micropolar parameter ( Γ = 0 . 1 –2.0) and buoyancy ratio ( N r = 1 –20), enabling a comprehensive assessment of both geometric and flow-induced effects on thermal and solutal performance. The results indicate that thermal radiation is the dominant heat transfer mechanism, producing an enhancement of approximately 56.5% in the average Nusselt number, while causing only a marginal change in mass transfer. Micropolar effects significantly improve overall transport, increasing the average Nusselt and Sherwood numbers by about 12.7% and 20.6%, respectively. In contrast, the Dufour effect reduces heat transfer by nearly 19%, whereas the Soret effect weakens mass transfer by approximately 21% within the investigated parameter ranges. These findings demonstrate that heat and mass transfer in magnetized NEPCM-based micropolar systems can be effectively tailored through a careful balance of radiation, microrotation, and cross-diffusive mechanisms, providing quantitatively reliable design guidelines for compact heat exchangers and modular thermal energy storage applications.