Heat transfer inside cooling system based on phase change material with alumina nanoparticles

The present study is devoted to numerical investigation of heat and mass transfer inside finned heat sink filled with nano-enhanced n-octadecane. Hydrodynamic equations were formulated using the transformed variables such as stream function and vorticity and solved in melt region with moving boundary. The unsteady melting process with convection heat transfer was formulated taking into account porous insertion between the solid fraction and liquid fraction. The complex investigation of governing parameters influences such as volume fraction of nanoparticles, finning length and intensity of heat generation inside the heat source on the heat and mass transfer was carried out. The impact of each parameter on the temperature distributions and the liquid volume fraction versus time was shown. The melting intensity at the simultaneous increase in thermal conductivity and viscosity at different loads was studied. Tit was found that addition of nanoparticles accelerates the melting process at the initial stage of melting due to the heat conduction in the solid and liquid phase change material (PCM). However, with time the convective mechanism of heat transfer develops in melt. The melting rate in pure paraffin is higher than the one for the nano-enhanced PCM. Using nano-enhanced PCM the efficiency of heat transfer is achieved with the growth of the radiator fins length. The addition of nanoparticles increases the melting rate at the time stages when the heat conduction predominates over the convective mode. Some optimal volumetric concentrations, in terms of minimum melting time, are also detected.