CFD simulation of mixing and power consumption in a tank with a low impeller clearance

High power consumption may be required to achieve a good mixing in a stirred tank system, and this is a major economic factor in the design of many industrial processes. Computational fluid dynamics (CFD) techniques were employed to study the effect of the impeller clearance on mixing and power consumption in a Rushton turbine stirred tank. The sliding grid (SG) and multiple frame of reference (MFR) approaches have been employed. Tracer-mixing studies, with conductivity meter and decolourization methods were employed to determine macro scale mixing time. The influence of the grid size, temporal and spatial discretisation schemes on mixing time was investigated. The simulation results were compared with experimental data obtained using a laser Doppler velocimeter (LDV). A comparison between the standard and a lower impeller clearance showed that a lower homogenization energy can be...