Study on Particle Response to Local Fluid Velocity in a Gas Particle Turbulent Flow

Solid particle response to local gas velocity was discussed based on the simulation results of instantaneous velocities of three-dimensional backward-facing step gas particle turbulent flow. Gas flow was simulated by the method of large eddy simulation and particle motion was calculated by the Lagrangian particle tracking model. Instantaneous particle response to gas velocity in two different typical flow regions was discussed. Some factors, such as the waveform similarity function and time-averaged method were used for quantitatively studying particle response regularity based on the relationship between the gas velocity and particle velocity for different size particles. It is shown that the smaller the particle is, the smaller the waveform similarity function value is. The extent that particle velocities make response to gas flow velocities in different flow regions is also distinct. Moreover, for time-averaged results, the quantitative results that particle velocities depend on gas velocities are obviously different in the main flow region. These studies also provide some reference for researches of improving particle stochastic separated flow models for turbulent two-phase flow and for studies of two-way coupling problem for two-phase flow.