Ricerc@Sapienza

Purpose–The purpose of this paper is to improve the lattice Boltzmann method’s ability to simulate amicroflow under constant heatflux. Design/methodology/approach–Develop the thermal lattice Boltzmann method based on doublepopulation of hydrodynamic and thermal distribution functions. Findings–The buoyancy forces, caused by gravity, can change the hydrodynamic properties of theflow.As a result, the gravity term was included in the Boltzmann equation as an external force, and the equationswere rewritten under new conditions.

Mixed convection heat transfer of air in a 2-D microchannel is investigated numerically by using lattice Boltzmann method. The effects of buoyancy forces on slip velocity and temperature profiles are presented while the microchannel side walls are under a constant heat flux boundary condition. Three states are considered as no gravity, Gr = 100 and Gr = 500. At each state, the value of Knudsen number is chosen as Kn = 0.005, Kn = 0.01 and Kn = 0.02 respectively; while Reynolds number and Prandtl number are kept fixed at Re = 1 and Pr = 0.7.