Computational fluid dynamics simulation of different impeller combinations in bioreactor

The influence of 4 kinds of different impeller combination on flow patterns,oxygen mass transfer coefficient kLα,air volume fraction,gas holdup(volume fraction) and power in a gas-liquid bioreactor was studied under the same operating conditions(rotation rate of impellers 400 r/min,gas rate 0.86 vvm and operating temperature 15 ℃) using computational fluid dynamics(CFD) numerical simulation method.The research results show that the Model 1 which has the radial flow impellers at both the top and bottom sides can provide the highest capacity of kLα.Meanwhile,the Model 2 3 with the assembled axial flow impeller at the top and the radial follow impeller at the bottom,have a better ability to mix the liquid and disperse bubbles.Compared with other three models,the Model 4,with the axial flow impellers at both top and bottom sides has lower power consumption,approximately 0.2 W/L.