Organic phase change materials melting with electrohydrodynamics (EHD): Numerical simulation and experimental validation

Electrohydrodynamics (EHD), as an active heat transfer enhancement technique, would dynamically manipulate the performance of latent heat thermal storage (LHTS) system. In this paper, the melting characteristics of octadecane with EHD were simultaneously investigated by numerical simulation and experiments. A numerical model based on the finite volume method was developed to solve the Poisson-Nernst-Planck equation, Navier–Stokes equation, and energy equation. The solid-liquid interface position, charge density distribution, velocity field, and liquid fraction were reported. The accuracy of the numerical model was evaluated by the experimental results. For the case of melting without EHD, the numerical results agree well with the experimental results. The relative error between the simulation and experiment is less than 20.0% for the case of melting with EHD. The melting time would be significantly saved with the increasing applied voltage magnitude and inner electrode temperature. The melting time with EHD would be reduced by 13.6 times compared to the natural melting case. The flow in the liquid phase is chaotic and the Coulomb force is dominant than the dielectric force and the buoyancy. In addition, the influence of electrode arrangement on the melting behavior is studied. The melting can be decreased by 1.26 to 1.84 times by adopting four electrodes compared to melting under the configuration of a single electrode with the same cross-section. The proposed numerical model provides a reference for designing and predicting LHTS performance with EHD.