Melting performance enhancement of phase change material with magnetic particles under rotating magnetic field. (June 2021) - Fan, Yubin
Highlights: A rotating magnetic field is introduced to accelerate the melting of PCM. The increment of average heat storage rate is in the range of 20–30%. Solid-liquid interface with particles under magnetic field trend to be vertical. Increasing rotational speed and particle fraction benefit to the melting process. Abstract: Low thermal conductivity of phase change materials (PCMs) has a negative influence on heat transfer rate which severely restricts the performance of latent thermal energy storage system. Unlike conventional methods that are paid attention to conduction enhancement, a method to accelerate PCM melting based on convection intensification is proposed in this paper. Magnetic particles dispersed in liquid PCM move circumferentially in heat reservoir with the effect of rotating magnetic field, leading to the forced convection in liquid PCM. Consequently, the melting process of solid PCM is accelerated. An experimental set-up of dodecanol melting in a side-heated cylinder is constructed to evaluate the effectiveness of the proposed method. Heat transfer characteristics of PCM are investigated in terms of solid-liquid interface, heat storage rate, and temperature distribution. Results show that through the proposed method total melting time could be reduced by 22.9% when rotational speed is 20 r·min −1, particles fraction is 1.0 wt%, and heating temperature is 35 °C, respectively. Besides, solid-liquid interface tends to be vertical due to the forced convection under magnetic field. Meanwhile, it is beneficial to improve the melting performance within the range of experiments by increasing magnetic field rotational speed and particles fraction.