Modulations on turbulent characteristics by dispersed particles in gas–solid jets

Abstract

A direct numerical simulation technique combined with a two-way coupling method was developed to study a gas–solid turbulent jet with a moderately high Reynolds number. The flow was weakly compressible and spatially developing. A high-resolution solver was performed for the gas phase flow-field and the Lagrangian method was used to trace particles. The modulations on flow structures and other turbulent characteristics by particles at different Stokes numbers were investigated. It is found that the particles at Stokes numbers of 0.01 and 50 can advance the development of the large-scale vortex structures and make the turbulence intensity profiles wider and lower, but the particles at a Stokes number of 1 delay the evolution of the large-scale vortex structures and decrease the turbulence intensities. The jet velocity half-width and the decay of the streamwise mean velocity in the jet centreline are reduced by all particles, in which particles at a Stokes number of 0.01 result in a larger reduction of the velocity half-width and particles at a Stokes number of 1 lead to a larger reduction of the streamwise mean velocity decay. All particles decrease the vorticity thickness, but increase the fluid momentum thickness. In addition, the two-way coupled particle distribution is more uniform than that of the one-way coupled case.