Numerical flow characteristics of microencapsulated phase change slurry flowing in a helically coiled tube for thermal energy storage

As a new heat transfer medium, microencapsulated phase change slurry (MPCS) has better heat transfer performance than water. The MPCS consists of microencapsulated phase change materials (MPCM) particles and carrier fluid (water). Many experiments and numerical simulations have been carried out on its heat transfer characteristics, but few focused on its flow characteristics. In this work, a numerical model of the MPCS flowing in a two-turn helically coiled tube under constant wall heat flux was established. The numerical simulation results showed that inlet velocity was the most important factor affecting pressure drop and pumping power consumption of the MPCS. Except the inlet velocity, the mass fraction was the major factor affecting the flow characteristics of the MPCS. The latent heat and wall heat flux had little effects on the flow characteristics of the MPCS. In addition, the possible motion trajectories of MPCM particles were calculated by using Discrete Phase Model (DPM) model, and the motion state of MPCM particles was visually displayed. (c) 2021 Elsevier Ltd. All rights reserved.