Flow and sedimentation characteristics of silica hard-shell microcapsule slurries treated with additives. (October 2019) - Suzuki, Hiroshi
Highlights: Flow characteristics of silica hard-shell microcapsules with phase change materials have been improves with surfactants. Combination additives of surfactants and of poly vinyl alcohol well depress the sedimentation of microcapsules with PCM. The addition of poly vinyl alcohol does not disturb drag-reducing effect of the surfactants. Abstract: The sedimentation and flow characteristics of micro-encapsulated phase change materials have been investigated. As a phase change material, trimethylolethane clathrate hydrate having 218 kJ kg −1 of latent heat was used and encapsulated in silica hard-shell microcapsules, which size distribution has two peak at 15 µm and 59 µm. A cationic surfactant, oleylbishydroxyethylmethylammonium chloride with a counter-ion, sodium salicylate was used as drag reducing additives and poly vinyl alcohol was used as a stabilizer. From the results, it was found that the combination additive prevents effectively the microcapsule sedimentation. The drag reduction was also observed to occur in the high Reynolds number region. Thus, the present additive was concluded to be promising for the latent heat transportation by use of silica hard-shell microcapsules containing phase change materials.