多层桨搅拌槽内的微观混合特性

在直径0.476 m的多层桨搅拌槽内，采用平行竞争反应工作体系，就不同的多层桨型组合、进料时间、搅拌转速及进料位置对产物分布的影响规律进行了系统的实验研究，并采用涡旋卷吸模型就加料位置等操作条件对产物分布的影响进行了模拟计算，模拟值与实验值吻合. 结果表明，对于多层桨搅拌体系，在液面处加料时产物分布主要由上层桨的桨型决定，底层桨的排出流区加料时主要由底层桨的桨型及功率决定. 卷吸模型能够较好地描述搅拌槽内的微观混合过程.

Micromixing Characteristics in a Stirred Tank with Multiple Impellers

The product distribution of competitive reactions in an agitated reactor is significantly affected by micromixing. A pair of competitive parallel test reactions were used to investigate the micromixing in a stirred tank of 0.476 m diameter with multiple impellers. One triple 3-narrow blade hydrofoil CBY impeller agitator and combination of one 6-hollow blade disk turbine HD-6 as bottom impeller with two CBY impellers were used in the experiments. The effects of feeding time, impeller speed, feeding location and agitator type on product distribution were systematically studied. For the multiple impeller systems, the product distribution is dominated by the impeller closest to the feeding location. The simplified micromixing model, the engulfment model, was used to predict the product distributions of triple CBY impellers. Good agreement can be found between the results predicted by the engulfment model and the experimental data. The results are of importance to the optimum design of multiple impeller industrial stirred reactors for fast complex reactions.