鼓泡塔内空气-醋酸体系流体力学参数的CFD-PBM耦合模型数值模拟

通过二维和三维CFD-PBM耦合模型对空气-醋酸体系中流体力学参数进行数值模拟,采用表面张力修正曳力模型与聚并模型,考察了醋酸浓度对鼓泡塔内气含率、气泡大小分布及轴向液速等参数的影响,与差压法、光纤探针和电阻层析成像技术（ERT）测量的实验数据进行了对比,并讨论分析了气含率和气泡直径等流体力学参数的模拟结果。结果表明,醋酸浓度在70%~80%（质量分数）范围内平均气含率存在最大值,且平均气含率的预测值在±10%误差内,三维模拟结果和ERT实验值吻合较好,说明修正后的模型在不同浓度醋酸体系中具有较好的预测性。     

气液并流向上填充鼓泡塔液体混合特性的研究

在内径为165 mm气液并流向上填充鼓泡塔中采用示踪法考查了表观气速、表观液速、液体黏度、填料大小等因素对液体轴向混合特性的影响。根据实验结果得出:Peclet准数随表观液速的增加而增大,轴向返混程度减小,而随表观气速或液相黏度的增加而Peclet准数略有减小,轴向混合程度增加。同时,填料的引入明显减少轴向混合程度,随着填料直径的增加,Peclet准数明显减少,轴向混合程度增大。根据实验结果,关联了实验范围内Peclet准数的计算式,为填充鼓泡塔反应器的设计与放大提供了一定的指导作用。     

电阻层析成像技术在气液(固)多相流动体系中的应用进展

Electrical resistance tomography (ERT) has been widely used in monitoring and measuring gas?liquid?(solid) multiphase flow systems as a fast, non-invasive, radiation-free, simple equipment compared to conventional methods and other tomographic modes. For the gas?liquid?(solid) multiphase flow system, the principle of ERT test was introduced, and the characteristics of ERT and other measurement technologies were analyzed in this work. The three important characteristics and process parameters (flow pattern identification, phase holdup, bubble size and distribution) of ERT were reviewed in detail. Problems to be solved in the application process of ERT technology in the gas?liquid systems were discussed (the standardization of flow pattern identification, the accuracy of identification process parameters, the equalization of time resolution and spatial resolution, etc.). Based on the development trend of ERT technology in the field of multi-phase flow parameter detection and its subsequent research directions, a model based on electrode array optimization, image reconstruction algorithm or 3D/4D field establishment was proposed, which combined the dynamic information and fluid dynamics numerical simulation of industrial process parameters. And ERT's rich flow field information can effectively verify the accuracy of mathematical simulation, real-time monitor and predict industrial processes, and effectively prevent or inhibit the uncertainty of chemical production process. At the same time, it was proposed to use the cross-knowledge between different disciplines to broaden the application fields of ERT, such as fluid mechanics in microscale equipment, biomedical testing diffusion properties of serum in dry tablets, online monitoring and analysis in the field of food processing, etc. As a visualization tool of fluid flow, ERT 2D and 3D real-time visualized flow information deepened the understanding of the complex characteristics of multi-phase flow, realized the purpose of optimizing operating conditions, improving efficiency, reducing costs and overall monitoring of production process, and promoted the application of ERT in chemical industry, petroleum, medicine, environmental monitoring, food processing, mineral flotation, material transportation and other fields.     

SEBS高黏度溶液气液鼓泡塔的流体力学研究

针对SBS加氢反应器开发与设计,以SEBS-1650己烷溶液为液相,采用差压法和床层塌落法研究了气液鼓泡塔中高黏度溶液的流体力学行为,考察了黏度对低表面张力溶液的气含率、大小气泡气含率、大小气泡上升速度和比表面积等因素的影响。结果表明,随黏度增加,大气泡增多,气含率明显降低,塔内流型处于湍流区;由床层塌落曲线确定鼓泡塔内存在三种类型的气泡：大气泡、小气泡及细小气泡,随黏度增加,小气泡与细小气泡逐渐减少;黏度对大小气泡的上升速度略有影响,比表面积随黏度增加而明显降低。根据实验结果给出了大小气泡气含率与平均气含率的计算公式。