Application Of Computational Fluid Dynamics Simulation For Typical Stirred Equipment Of Fermentation Industry

On the basis of Computational Fluid Dynamics (CFD) simulation, fermentation tank ventilation and glutamic acid crystallizer out of typical stirred industrial equipments are investigated to provide related researches and production with data and technical support.In the first section, using FLUENT (V6.3, Fluent Inc., USA) as computational tool, mass transfer, mixing, features of dissolved oxygen and power consumption of single blade were studied under the condition of different rotation speed and gas speed. Results showed that single blade tank was difficult to meet the need ofε-poly-L-lysine fermentation at laboratory.According to above results, the tank was optimized by increasing the number of impeller and changing the type of impeller. The effect that 4 kinds of combination were studied (1. the up and down were both six-straight-blade-turbine,2. the up was propeller and the down was six-straight-blade-turbine,3. the up was triple bladed paddler and the down was six-straight-blade-turbine,4. the up was triple bladed paddler and the down was propeller) of 3 different paddles gave to flow distribution, shear force and power consumption, which confirmed with fermentation. It indicated that No.2 tank showed the best fermentation result, which complied with the CFD simulation result. Therefore, the CFD simulation was available to guide and optimize fermentation of filamentous microorganism and other types of fermentation.In the second section, the structure of 50m3 crystallizing tank was optimized. On condition of ensuring the mixing effect, reducing shear force and power consumption resulted in high production quality and low energy consumption. It showed that:(1) The height of liquid level, whether the aid of draft tube was present or not, and wherever the draft tube was placed, the differences of paddles and the modification of diameter of paddles all affected standard concentration deviation (σ).(2) Whileσ<0.2 the uniform suspension status was realized, on the condition that D=350mm and N=240r·min-1, and the minimum average shear force and the minimum power.