Numerical simulation of the high Reynolds number slit nozzle gas-particle jet using subgrid-scale coupling large eddy simulation

Large eddy simulation (LES) model in which the effect of the particle exist ence on subgrid-scale flows have been taken into account is proposed. The k inetic energy of the subgrid-scale flow to obtain a turbulent viscosity coe fficient of the subgrid-scale flow in the LES has been calculated in assumi ng that the interaction terms between the gas and particles, the turbulent production term and the viscous dissipation term were balanced with each ot her in the kinetic energy equation of the subgrid-scale turbulent flow. Usi ng this model, three-dimensional Navier-Stokes equations and the Lagrangian particle motion equations are simultaneously solved to describe the high R eynolds number (Re = 10(4)) gas-particle jet flow and the effect of particl e existence on it. The calculated results of air and particle turbulent cha racteristics which are mean velocity, turbulent intensity and Reynolds stre ss distributions are in good agreement with experimental data measured by a laser Doppler velocimeter. The existence of particles usually reduces the grid-scale turbulence in the high Reynolds number developed turbulent jet. On the other hand, the parti cle existence which is some kind of flow disturbance produces grid-scale fl uctuations in the initial and the transitional regions of the jet and then it increases the air turbulent intensity. When particle size is much smalle r than the grid size, the particle existence reduces the subgrid-scale turb ulence. However, when the product of the particle relative velocity and the particle concentration gradient is very large, the particle existence is a ble to increase the subgrid-scale turbulence. (C) 2001 Published by Elsevie r Science Ltd.