The flow and heat transfer characteristics of phase change emulsions (PCEs) in a circular tube have been investigated. The PCEs were heated under constant heat flux. The wall heat flux and mass fraction of the dispersed phase change material (PCM) particles were varied as experimental parameters. The PCEs showed Newtonian fluid behavior when the PCM mass fraction was less than 20 mass%. When the PCM mass fraction was 30 mass%, the PCE showed pseudoplastic fluid behavior. The Nusselt number of the PCEs is higher than that of the single-phase fluid because of latent heat absorption accompanying melting of the PCM particles. The heat transfer characteristics of the PCEs for melting PCM particles were also investigated using a numerical model, and the results were compared with the experimental results. The numerical results approximately agree with the experimental results when the PCM mass fraction is 20 or 30 mass%. (c) 2017 Elsevier Ltd. All rights reserved.