Design and performance evaluation of a novel electrohydrodynamically enhanced PCM heat sink

The present work introduces a novel approach to enhance the thermal performance of a phase change material (PCM) heat sink by integrating charge injection-induced electrohydrodynamic (EHD) flow. A detailed numerical investigation is performed to evaluate the effectiveness of the EHD-enhanced PCM heat sink. The solid–liquid phase change process is modeled using a stationary grid approach based on the enthalpy-porosity method. Based on the finite-volume method (FVM) within the OpenFOAM framework, a numerical solver is developed to solve the coupled system of equations governing fluid flow, heat transfer, melting, and electrostatics. The heat sink is exposed to a high heat power input of 10 W, and the resultant melting, flow, and heat transfer characteristics are studied. The numerical model considers the conjugate heat transfer in the electrodes and walls of the heat sink. The electric potential distribution in the heat sink walls is also considered. The induced electroconvective flow due to the applied electric field enhances flow velocity, alters flow structure, accelerates melting, and augments heat transfer. The heat dissipation mechanism in the EHD-assisted PCM heat sink is analyzed, and its thermal performance is evaluated in terms of heat dissipating capacity at varying applied voltages and orientations. The assistance of the EHD flow leads to a notable reduction in the total melting time. The heat sink exhibits equal performance irrespective of the orientation due to the presence of the electric field. Higher applied voltages result in higher heat dissipation capacity. A maximum of 61.45% increase in heat dissipating capacity is achieved for the parameter space considered herein. The increased heat dissipation capacity is almost ten times higher than the extra power required to generate the EHD flow. The results of this study underscore the viability and economic feasibility of EHD-assisted PCM heat sinks for effectively dissipating high-density heat fluxes.