Study on the solid–liquid suspension behavior in a tank stirred by the long-short blades impeller

Abstract

We investigated the solid–liquid suspension characteristics in the tank with a liquid height/tank diameter ratio of 1.5 stirred by a novel long-short blades (LSB) impeller by the Euler granular flow model coupled with the standard k–ε turbulence model. After validation of the local solid holdup by experiments, numerical predictions have been successfully used to explain the influences of impeller rotating speed, particle density, particle size, liquid viscosity and initial solid loading on the solid suspension behavior, i.e. smaller particles with lower density are more likely to be suspended evenly in the liquid with higher liquid viscosity. At a low impeller rotating speed (N), increase in N leads to an obvious improvement in the solid distribution homogeneity. Moreover, the proposed LSB impeller has obvious advantages in the uniform distribution of the solid particles compared with single Rushton turbine (RT), dual RT impellers or CBY hydrofoil impeller under the same power consumption.