Control of the melting process in a rectangular energy storage chamber filled with phase change material in the presence of an oscillating and rotating cylinder

Abstract

In the present research, the efficacy of rotating and oscillating cylinders on the melting process in a rectangular chamber has been investigated numerically. Porosity-enthalpy model has been used to model the melting process. The effect of the radius, location, rotational and oscillating speed (amplitude and frequency) of the cylinder, the presence of different arrangements of the cylinder and the temperature changes of the active boundary on the liquifying process have been investigated. As the cylinder has an oscillating motion, the dynamic mesh is employed. The phase change material (PCM) is Lauric acid. The consequences reveal that the existence of the cylinder betters the rate of the melting process, and the best melting process occurs at R = 0.3, and the time required for the complete liquifying of the PCM for this state is lessened by 12.84 % compared to the state with R = 0.01. The rotating cylinder reduces the PCM liquifying rate, so that by selecting the rotational speed of −3 and + 10 rad/s, the average melting fraction of PCM has decreased by 7.96 and 8.67 %, respectively, compared to the fixed cylinder state. The oscillating movement of the cylinder improves the liquifying rate. Increasing the oscillation range and frequency will decrease and increase the liquifying rate, respectively. The temperature changes of the active boundary with time have improved the melting process compared to the constant temperature state. In the cases where the average Nusselt number increases, the melting rate has decreased. Among the arrangements considered for the cylinder arrangement, the best melting performance has been observed when two cylinders are placed horizontally in the chamber.