文档介绍：2005 Fluent 中国用户大会论文集
LES of Mixing Time in a Stirred Tank with a Rushton Turbine
MIN Jian, GAO Zheng-ming and SHI Li-tian (闵健,高正明,施力田)
School of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China
Abstract The mixing process in a stirred tank of m diameter with a Rushton turbine was numerically simulated by using
computational fluid dynamics (CFD) package . Large eddy simulations (LES) with Smagorinsky-Lilly subgrid
scale model puted to simulate mixing process, the turbulent flow field and mixing time. The impeller was modeled
using the sliding mesh model. The hybrid meshes method was chosen to divide the whole calculated region into two parts, one
compassed impeller using the unstructured grids, and the other was the bulk of tank using the structured grids. Based on the
response curve of tracer, the mixing time predicted by LES was in a better agreement with the experimental than the traditional
Reynolds-averaged Navier-Stokes (RANS) approach. The results show that LES is a good approach to investigate unsteady
and quasi-periodic behavior of the turbulent flows in stirred tanks.
Keywords LES, Smagorinsky-Lilly subgrid scale model, mixing time, Rushton turbine
INTRODUCTION
The mixing time, θm, is the time required to mix the added secondary fluid with the contents of the vessel
until a