Study of the melting performance of shell-and-tube latent heat thermal energy storage unit under the action of rotating finned tube

Compared to non-uniformly arranged fin, uniformly arranged fin can achieve better complete melting-solidification performance, but the uniform arrangement of fin does not perform well in the melting process. In order to strengthen the melting process when the fin is arranged uniformly, the method of rotating finned tube is proposed in this paper. The melting process of PCM under the action of rotating finned tube is numerically investigated. The domain-averaged synergy angle and thermal energy storage rate (TESR) index is introduced. The effect of rotational speed and the number of fins are analyzed. The results show that the rotating finned tube can enhance the convection of liquid PCM and reduce the domain-averaged synergy angle in the phase change region. Compared to static finned tube, rotating finned tube can reduce the total melting time by 30.3% at a rotational speed of 4 rpm. This paper recommends that the rotational speed of the finned tube should be no less than 2 rpm. The thermal energy storage rate (TESR) can be increased by 79.02% after raising the rotational speed of the finned tube from 0 rpm to 16 rpm. In addition, increasing the fin number allows the finned tube to start rotating at an earlier stage. When the fin number is increased from 4 to 10, the dimensionless start time of rotation is reduced by 36%.