Numerical flow visualization of fully-developed turbulence channel flow laden with particles of binary sizes

Particle-laden flows are widely appeared in many engineering practices and environmental phenomena, such as cyclone separator, powder classifier, pneumatic conveying, fluidized beds, pollution diffusion and dust storms, etc. In addition, the non-invasive diagnostic technologies of experimental fluid mechanics for the measurement of fluid velocity are mostly made of the seeding (or foreign) particles instead of fluid itself, such as particle image velocimetry, laser Doppler velocimetry, etc., and are also directly related to the phenomena of particle-laden flows. Thus, in the measurements of turbulent flow quantities of the two-phase flows even laden with mono size of particles by using the non-invasive optical diagnostic technologies, there still exist two sizes of particles in the flow field. One is the originally loaded particles, while the other is the seeding particles which are typically in the order of magnitude of 10⁰ m in size. Detailed interferences on turbulent dispersion motion between the large and small particles are hard to be studied experimentally. Modelling simulations which consider four-way coupling mechanisms and rough-wall effect are performed in a fully developed turbulent channel flows laden with mono-size particles together with and without seeding particles were performed in this study. It is found that the input of seeding particles with a typical number density in the flow does not affect the predictions of the turbulent properties of particles.