| Bio-Ethanol is a crucial renewable energy, and the study of thefermentation process and equipment are of important application value.The study of mixing and the design of fermentation reactors with theassistance of Computational Fluid Dynamics （CFD） method canovercome the deficiency of experience design methods and help with theinnovation of technology and development of the theory.The CFD and experimental methods are used to study the mixingphenomena in the reactor of the fermentation. This mixing was achievedby the combined actions of mechanical horizontal impellers, an externalrecycle flo and the gas-induced mixing by CO2-bubbles formed duringthe bio-reaction.The impellers created jet flow which affected the liquid at thebottom of the tank, the deposition of solids could be alleviated by thecone convex in the middle of the tank, and the power of the mixers wasreduced by10%after the optimization of the installation of the mixers.The experimental results of tracer response determined the relevantbubble characteristics and the induced liquid circulation flow: bubblesizes determined their rise velocities in swarms; whereas bubble volumeand associate wake in theory determined bubble-induced mixing.The recycle flow played an limited role of mixing while it was verycrucial in cooling of the mash.By comparing of the three actions, the rising bubbles played the keyrole in the mixing, then it follows the mechanical agitation, and theimpact of the recycle flow was the most limited. |
