Thermal-hydraulic analysis for alumina/water nanofluid inside a mini-channel heat sink with latent heat cooling ceiling-An experimental study

In this paper, an experimental investigation is carried out to evaluate the heat dissipation performance of the parallel mini-channel heat sink with the latent heat cooling ceiling. The heat sink is under the influence of an isothermal heating from the below. To enhance the cooling capacity of the system, the alumina/water nanofluid with various mass fractions of nanoparticles is considered as the working fluid. A micro-encapsulated phase change material layer is installed on the ceiling of the heat sink to cool down the fluid along the length of the heat sink. The experiments are performed for different values of mass fraction of nanoparticles, Reynolds number, mean temperature of bottom wall, inlet temperature of fluid, and mean temperature of cooling upper plate. The effects of these parameters on the friction factor, the mean Nusselt numbers dependent on the inlet and bulk temperatures difference, and the coefficient of performance are investigated. The experimental results indicate that the inlet temperature of the nanofluid has negligible effects on the friction factor for the base fluid Reynolds numbers of 483 and 968. However, the friction factor decreases as the inlet temperature increases for the base fluid Reynolds number of 161. The mean Nusselt numbers dependent on the inlet and bulk temperatures difference decrease by using a working fluid with the higher inlet temperature. The coefficient of performance increases with increasing the mean temperature of bottom wall from 50 degrees C to 55 degrees C. Finally, the mean temperature of cooling upper plate has negligible influences on the coefficient of performance.