Convective heat transfer characteristic of latent functionally thermal fluid in a flat tube

An experimental investigation on the convective heat transfer characteristic of 5wt%-20wt% latent functionally thermal fluid flowing in a flat tube is presented in this work. The influences of the mass flow rate and the mass fraction of microencapsulated phase change material (MPCM) on the heat transfer performance are conducted. The results of the experiment show that at the region of small flow rate, the heat transfer performance of latent functionally thermal fluid is better than that of water and increases with the increase of concentration of MPCM, while not as good as that of water near the entrance where the flow rate is high. Evaluated by the modified Nusselt number, the average heat transfer rate of 10wt% and 20wt% suspensions is improved by 6.7% and 16.2% respectively compared to that of water at the entrance region. The latent functionally thermal fluids are approximately Newtonian fluids and their viscosities fit well with the Vand model.