Laminar Flow Heat Transfer Characteristics of Phase Change Emulsion in a Circular Tube

Abstract

In the present study, the heat transfer characteristics of a phase change emulsion (PCE) were investigated experimentally to use it as one of the high functional thermal media. The wall heat flux, mass fraction of phase change materials and particle phases were chosen as factors which effect on the heat transfer characteristics of PCE. The particle phases were divided into three cases that solid phase, liquid phase and melting. Two kinds of phase change materials (PCM), n-hexadecane and n octadecane were used as the dispersed phase of PCE. The experiments were carried out in a laminar flow region. The results showed the local Nusselt number of PCE in cases of PCM particles were in solid or liquid phases roughly agreed to the empirical values which were calculated by an empirical equation for the single phase flow. On the other hand, when PCM particles were melting, the local Nusselt number of PCE became 1.3 – 1.8 times higher than the empirical value. Furthermore, the results of PCE with 20 mass% PCM roughly agreed to numerical values obtained by solving the energy equation for a steady two dimensional developed flow in a circular duct applying FDM.