Lattice Boltzmann simulation of mixed convection of nanofluid with different heat sources in a double lid-driven cavity

In this study, mixed convection heat transfer of Al2O3/water nanofluid in a double lid-driven cubic cavity with different heat sources was numerically investigated. The lattice Boltzmann method (LBM) was developed to solve the governing equations. The effects of nanoparticle volume fraction, Reynolds number and Richardson number on heat transfer characteristics were examined. The results show that they have great effects on both velocity profiles and heat transfer performance. Additionally, the effects of different lid directions and heat sources on heat transfer were explored. It is found that the case of cold wall moving down and hot wall moving up double lid-driven cavity has the best heat transfer performance. Numerical results also indicate that different heat sources have significant impacts on both the local Nusselt number distribution on the hot wall and temperature field in the cavity. In order to improve the computation efficiency, the Open Multi-Processing (OpenMP) was employed for the parallelization of the proposed 3D LBM model. The phenomenon of super linear speedup was noted and discussed.