Computational fluid dynamics simulation of a stirred tank reactor

Abstract

Stirred tank reactors are used routinely in chemical processing industries. Mixing and dispersion in such reactors depends on the geometry of the reactor and impeller. In addition, CFD simulations are an important tool for characterizing flow and turbulence. Towards this end, the flow field inside a stirred tank reactor is simulated by means of ANSYS Fluent CFD package. Computational geometry and mesh are generated in ANSYS. Simulations are conducted using the Multiple Rotating Frame (MRF) technique in conjunction with the k-∊ turbulence model. MRF is a computationally efficient technique, however the solution may depend on the size of the inner domain near the impeller. Therefore, it is important to validate the technique by comparison with the experimental data. In this work, the model is implemented in ANSYS Fluent and the simulated velocity profiles are assessed against the experimental profiles available in the literature. The simulations do describe the overall features of the flow well, however some discrepancies are noted. Suggestions for extending this work for proper evaluation of the MRF technique and various turbulence models are given. Once properly validated, the technique can be used for realistic evaluation of the effect of reactor and impeller geometry on mixing and turbulence.