The vortex settling chamber is an efficient and economical type of sediment extracting device. To obtain comprehensive information about the flow characteristics in vortex settling chamber, and to explore its working mechanism, the large eddy simulation model and VOF (volume of fluid) method were applied to simulate water-air two-phase flow in vortex settling chamber. The calculated results of average velocity were in good agreement with experimental data measured by Laser Doppler Velocimeter (LDV). The simulation results gave some new understanding on the three-dimensional velocity distribution. Based on the calculation secondary flow was found clearly and it was critical for transporting and removing sediment efficiently in vortex settling chambers.
