Numerical analysis on mixing performance of logarithmic spiral impeller

Abstract

Mixing performance of the solid-liquid two phase system in a mixing tank equipped with a logarithmic spiral impeller is studied with fluid dynamics software FLUENT. Based on the kinetic theory of granular flow, the basic control equations of the E-E model are established. A multiple reference frame (MRF) method and the RNG k-ε turbulence model are chosen to simulate solid-liquid flow performance and results are compared with that of the four blade turbine (MK) and the six blade turbine (PY). Research shows that the logarithmic helicoidal impeller improves solid-liquid axial-flow performance, and the concentration, power consumption and the mixing time of it are better compared with the PY and MK impellers. For a wide range of mixing velocities, the concentration of the sludge particles is always lower in the upper position to impeller than in the lower position. With the increase of velocity, the power consumption raises gradually, the uniformity of solid particle distribution decreases and the mixing time reduces.