CFD优化管线式高剪切混合器停留时间分布

Optimization of residence time distribution of in-line high shear mixer by CFD

基于计算流体力学(CFD)的方法,采用Fluent软件,结合大涡模拟(LES)湍动模型和组分物料运输模型(SPE)对中试规格的管线式叶片-网孔型高剪切混合器的停留时间分布(RTD)进行预测,与实验结果相比,其误差在14%以内,说明此方法具有较高的可靠度。基于此方法,研究了定子开孔形式、腔室结构及定转子安装方式对停留时间分布的影响,使其适用于快速反应过程。结果表明:圆形、菱形、"S"形以及齿形4种不同开孔形式的定子,圆孔开孔定子效果最优;轴向长度缩短至与出口管径相同,蜗壳形状的腔室外壳,出口管与腔室相切时效果最优;定转子偏心安装能够改善其效果,但功耗增加。经过优化后的反应器具有广泛的应用,特别的是将其用于许多快速化学反应过程时,由于停留时间短、混合效果好,其混合性能明显优于许多传统的反应器。

In this paper,based on computational fluid dynamics（CFD）,the large eddy simulation model（LES）combined with species transport model（SPE）was successfully applied to predict the residence time distribution（RTD）of pilot plant in-line blade-screen high shear mixers（HSM）. The predicted RTDs were validated against experimental data and the relative errors were less than 14%. This method was used to explore the effect of structural parameters like geometry of the holes of stator,structure of chamber and installation method on RTD to apply to fast chemical reaction processes. The results showed that the stator with circular holes was better than that with teeth or rhombus or ＂S＂ shaped holes. HSM with a reduced axial length same as the outlet diameter,volute chamber and tangential outlet was the optimal form. The rotor was eccentricly installed to improve its effect with requirement of higher power. The optimized HSM had a wide number of applications especially for the fast chemical reaction processes because of its short residence time and excellent mixing performance.