Heat Transfer Characteristics of Upper/Lower Surface Heating of Microcapsule Slurry in a Horizontal Duct

Abstract

This study presents the heat transfer characteristics of combined convection with forced convection and natural convection of microcapsule slurry that is a mixture of water and microcapsule which contains latent heat storage material. As a results, average heat transfer coefficient increases slightly by phase change, because of the effect of the latent heat of microcapsule in upper surface heating condition. In the lower surface heating condition, the local heat transfer coefficient on the upstream side increases by the phase change. The average Nusselt number have almost same value and tendency regardless of the increase of modified Reynolds number. This is because natural convection have a greater effect on the combined convection. Rayleigh number increases by phase change. It can be thought that promote heat transfer caused by the greater effect of natural convection due to density difference from phase change, rather than the effect of latent heat by phase change.