Thermal Lattice Boltzmann Analysis of Natural Convection Heat Transfer from Partially Open Cavities

In this research, the heat transfer natural convection from partially open cavities is evaluated with thermal lattice Boltzmann method. In this study different boundary conditions for all walls are investigated for example constant temperature, adiabatic walls and one heated walls for different open ratios. The study is carried out for a range of Rayleigh numbers and Prandtl number around 0.718 for air. The numerical simulation was conducted under different heat fluxes ranging from 0 to 480 W/m2 and opening ratio 0.4, 045 and 0.5. The purpose of this work was the steady state evaluation of the natural convection heat transfer inside the cavity under different boundary conditions by considering gravity effects. Finally, the effects of heat transfer on streamlines in partially open cavities are discussed. For this purpose, the equations of conservation of mass, momentum and energy were solved using different boundary conditions by thermal lattice Boltzmann method. In order to simulation use D2Q9 lattice for velocity and temperature distribution. Results are presented as well as the variation of average Nusselt number at the isothermal walls and compared with the established CFD tools using PHOENICS code referenced through literature. The results show the average Nusselt number of the isothermal walls was found to be dependent on the geometry of the vent of the cavity. For the top vented case, the average Nusselt number increases with increase of opening ratio. Also with the increase of the opening ratio, buoyancy driven flow is more effective inside the cavity, hence, good air circulation is observed. Also the average Nusselt number increase with increase of the heat flux.

کلیدواژه ها:

natural convection ، thermal lattice Boltzmann ، partially open cavities ، Nusselt number