Abstract
In this paper, a numerical method is used to investigate the conjugate heat transfer of a phase change material (PCM) suspension in a circular tube under external cooling convection. The following parameters and ranges were considered: dimensionless tube wall thickness, t w (0–0.5); wall-to-fluid thermal conductivity ratio, k w f * (0.1–10); volumetric fraction of PCM particles, c v (0.1); Biot number, B i o (1); Stefan number, Ste (0.1); and Peclet number, Pe (1000). The results show that the wall thermal conductivity considerably affects the outer/inner wall temperature of the tube, the average temperature of the working fluid, and the volumetric liquid fraction of PCM particles. Thus, wall conduction effects must be properly accounted for to model heat transfer in a PCM suspension in tube flow.
Highlights
Fine solid-liquid phase-change material (PCM) particles can be dispersed in a carrier or suspended in a working fluid to form PCM slurries or suspensions
Polymer materials cover the PCM to create a barrier between the dispersed phase (PCM) and the dispersion medium that results in the suspension of PCM particles in the dispersion medium
The results showed that when the flow rate and the heat flux are in a proper range, the tube wall temperature along the heated section can be effectively suppressed with increasing mass fraction of the nano-PCM particles in the water-based phase-change nanofluid compared with that of the pure water
Summary
Fine solid-liquid phase-change material (PCM) particles can be dispersed in a carrier or suspended in a working fluid to form PCM slurries or suspensions. Polymer materials cover the PCM to create a barrier between the dispersed phase (PCM) and the dispersion medium (such as water and glycerol) that results in the suspension of PCM particles in the dispersion medium. The prepared PCM particles have a relatively fixed size and shape and relatively stable physical properties compared to particles prepared by other methods. These materials have the disadvantages of high cost, a difficult manufacturing process, reduced heat transfer efficiency from the polymer surface coating, and expansion and cracking after repeated heating. The addition of appropriate emulsifiers reduces the surface tension between the dispersed phase and the dispersion medium to produce a stable emulsion of PCM particles uniformly suspended in the dispersion medium
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