Dispersion and Flow Characteristics of Super-Hydrophobic Marshmallow-Like Gel Particles in CMC Solution for Latent Heat Transportation

Abstract

To utilize a super-hydrophobic tetradecane-adsorbed marshmallow-like gel as a phase-change material (PCM) as a carrier for latent heat transportation by mixing the gel particles with sodium carboxymethyl cellulose (CMC) solution, the dispersion characteristics and flow characteristics of a marshmallow-like gel slurry were investigated. To investigate the dispersion characteristics of the slurry, visual observation of the slurry under static conditions was performed while varying the concentration of CMC, and the apparent dispersion fraction was determined for quantifying dispersion characteristics. The apparent dispersion fraction stabilized within 2 h. At CMC concentrations of < 0.4, 0.6-2, and > 3 wt%, the apparent dispersion fraction increased, remained constant, and reached the complete dispersion state, respectively. At several concentrations, the viscosity of the liquid layer of the gel slurries was lower than that of the pure solution, coinciding with the range where the apparent dispersion fraction increased. Therefore, it was found that the adsorption of CMC onto the surface of marshmallow-like gel affects the dispersion characteristics of marshmallow-like gel slurry. To investigate flow characteristics, friction factor of CMC solution and marshmallow-like gel slurry against Reynolds number was measured. From the results, it was confirmed that the shear-thinning of the CMC solution affected the flow characteristics.