Abstract: Based on the Euler - Euler two-fluid model and population balance model, using MRF (multiple reference frame) method, the flow field of the rushton turbine stirred reactor and airfoil axial flow stirred reactor in fermentation tank is analyzed by Fluent. The information of the oxygen content and the size of bubble in the tank is obtained. The simulation results show that the axial flow produced by the airfoil axial flow stirred reactor and the radial flow produced by the rushton turbine stirred reactor interact with each other. The oxygen distribution is relatively uniform. There is an oxygen concentration near the mixing shaft and heat exchanger tube. The overall gas holdup is reached to 2.22%. The stirring power of the fermentation tank calculated by the simulation is 117.81 kW. The results of computational fluid dynamics (CFD) on fermentors are of industrial application value. The theoretical method used in the research has certain theoretical significance in solving the problems.

Key words: amino acid fermentation, Euler model, multiple reference frame, gas holdup, population balance model