A numerical study on the migration of a neutrally buoyant particle in a Poiseuille flow with thermal convection

Abstract

The migration of a neutrally buoyant particle in a Poiseuille flow with thermal convection is investigated with the double-population lattice Boltzmann method. Compared with the isothermal case, the migration of the particle is notably affected by thermal convection. Five competing mechanisms are responsible for the lateral migration of the particle, i.e., wall repulsion due to lubrication, inertial lift related to shear slip, a lift due to particle rotation, a lift due to the curvature of the undisturbed velocity profile and a lift induced by thermal convection. Within the parameter range examined (Gr<2000,Rec<200), a critical Grashof number Grc is identified, beyond which the equilibrium position is insensitive to the initial position. Furthermore, a power law dependence of the critical Grashof number Grc on the channel Reynolds number Rec is discovered. In addition, with the channel Reynolds number Rec increasing, the forced flow relative to the particle is becoming stronger, leading to a declining effect of thermal convection.