【作者】 曹逸；

【导师】 毛忠贵；

【作者基本信息】 江南大学 ， 发酵工程， 2010， 硕士

【摘要】 本工作基于计算流体力学数值模拟对典型搅拌工业设备中的通气发酵罐和谷氨酸结晶罐进行研究,以期为相关的研究和生产提供数据和技术支持。论文第一部分以用于实验室聚赖氨酸发酵的5L通气搅拌生物反应器为研究对象,采用FLUENT(V6.3, Fluent Inc., USA)作为计算平台,首先考察了单桨叶在不同转速下和不同气速下的传质、混合、溶氧特征以及功率消耗。结果表明：单桨叶发酵罐难以满足实验室聚赖氨酸微生物发酵的需要。根据上述实验结果,对该罐进行了优化,增加桨叶数目和桨叶类型。研究由3种不同桨叶构成的4种组合方式(1、上下档位均为六叶直桨；2、上档位螺旋桨,下档位六叶直桨；3、上档位三折叶桨,下档位六叶直桨；4、上档位三折叶桨,下档位螺旋桨)对流场、剪切力、气含率和功率等的影响,并进行发酵实验验证。结果发现,2号罐有着最好发酵表现。这和CFD数值模拟得出2号罐综合表现最佳的结果相一致,证实了CFD数值模拟方法指导、优化微生物发酵的适用性。论文的第二部分对50m3谷氨酸结晶罐的结构进行优化。在保证混合效果的前提下,降低剪切力和功率,并节省能耗和保证产品高质。结果表明：(1)液面的高度,是否安放导流筒和其安放的位置,桨叶的不同以及桨径的变化都对标准浓度差σ有很重要的影响。(2)满足均匀悬浮状态,且剪切力最小,功率消耗最少的方案为D=350mm,N=240r·min-1。更多还原

【Abstract】 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.更多还原