Turbulence Properties of Solid-Liquid Flow in the Near-Wall Region of a Stirred Tank

The experiment was performed in a flat-bottomed cubic tank and equipped with a down-pumping 3-blade CBY propeller, investigating solid-liquid two-phase flow in the near-wall region by using 2D-PIV technique. Flow fields with ten different volumetric particle concentrations were investigated, including the single-phase flow. Because measurement is taken in the plane which is 2 mm from the wall, and root-mean-square velocity in the radial dimension could be omitted compared to the other two dimensions, flow field is considered to be two-dimensional. The mean velocity, turbulent kinetic energy and turbulent dissipation rate and their relationship with particle concentration were obtained and examined in this work. The increasing particle concentration decreases the flow mean velocity but increases the turbulent dissipation rate, while the turbulent kinetic energy (TKE) presents a complicated trend. When the particle concentration is below 0.9%, as in most previous studies did, TKE is attenuated; when the concentration grows up to 4%, TKE increases as well.