Convective heat transfer characters of nanoparticle enhanced latent functionally thermal fluid

The latent heat of the microencapsulated phase change material (MPCM) increases the effective thermal capacity of latent functionally thermal fluid. However, researchers found that the heat transfer performance of such fluids was diminished due to the reduction of the low thermal conductivity of MPCM. For this reason, the nanoparticle enhanced latent functionally thermal fluids were formulated and the heat transfer behaviors of these fluids in a vertical circular tube at the laminar regime were conducted. The result showed that slurries containing 0.5% TiO₂ nanoparticles by mass and 5%–20% MPCM by mass exhibited improved heat transfer rates in comparison with the conventional latent functionally thermal fluid and that the enhancement increased with the increasing MPCM concentration and up to 18.9% of the dimensionless wall temperature was reduced. Supported by the National Natural Science Foundation of China (Grant No. 50076020)