Forced convective heat transfer of solar salt-based Al₂O₃ nanofluids using lattice Boltzmann method

Though solar salt has been used in concentrated solar plants, the small specific heat capacity and low thermal conductivity still set a limitation on further application. A combination with nanoparticles shows potential to overcome these disadvantages. In present work, a freeze-drying method was employed to formulate solar salt-based Al₂O₃ nanofluids to modify the effective thermal properties. The investigation of forced convective heat transfer was taken by a modified lattice Boltzmann method. The effect of Al₂O₃ nanoparticle mass fractions on both effective c_p and heat transfer performance was analyzed. Results indicate that within the nanoparticle mass fraction range (0–2.0%), c_p and heat transfer coefficient increase with the increase of nanoparticle mass fractions. With 2.0 wt% Al₂O₃, the enhancement on effective c_p, heat transfer coefficient and Nusselt are 12.33%, 7.26% and 3.52%, respectively. In the meantime, a comparison between simulation results and Shah-London correlation prediction was carried out and good agreement was obtained.