Lattice Boltzmann method and large-eddy simulation for turbulent impinging jet cooling

In this paper, a large-eddy-based lattice Boltzmann model for energy equation is proposed to simulate the heat transfer phenomena of impinging jet flow. The hydrodynamic properties of two-dimensional turbulence are obtained by solving vorticity-stream function formulation with similar lattice Boltzmann model. The simulation results of a lid-driven flow and a backward-facing flow show the validity of the present model for a closed or an open flow field. For impinging jet flows, the cooling efficiency on the surface under constant-temperature or constant-heat-flux condition is investigated. The flow is found to be laminar or turbulent depending on not only the Reynolds number but also the ratio of jet-to-surface distance to jet exit width. In the laminar jet flow, stationary vortices formed near the surface reduce the thermal diffusibility, while the transient moving vortices remove the energy from hot surface rapidly. Therefore, the cooling efficiency of a turbulent jet flow is better than that of a laminar jet flow.