催化剂颗粒在弯道与渐扩管组合管系内的运动分布特征

李相鹏，洪滔，高增梁

(浙江工业大学 机械工程学院，浙江 杭州，310032)

摘 要：采用数值模拟方法对弯道与渐扩管相连的管道内气固两相流运动分布特性进行研究。主要分析弯道和渐扩段气相流场分布特征及气相回流卷吸作用下颗粒运动分布特性，研究沿出口水平管段二次流结构发展变化及其对颗粒分布及沉降的影响。针对不同入口速度下，水平管内气流速度、截面平均二次流速度和颗粒质量浓度分布规律进行研究分析。研究结果表明：沿弯道后的水平管道，二次流速度很快下降；二次流对颗粒的卷吸搬运作用，降低颗粒在管道截面的局部聚集浓度；当入口气流速度为4 m/s或更小时，水平管内上升二次流速度较小，颗粒沉降现象明显；当速度增大到6 m/s，水平管截面颗粒质量浓度分布较均匀。

关键词：催化剂颗粒；气固两相流；弯道；渐扩管；数值模拟

Motion and distribution of catalyst particles in pipe system combined with elbow and diverging tube

LI Xiang-peng, HONG Tao, GAO Zeng-liang

(College of Mechanical Engineering, Zhejiang University of Technology, Hangzhou 310032, China)

Abstract:Numerical simulation method was employed to study the gas-solid two-phase flow in pipe system combined with elbow and diverging tube. The gas flow fields and particles distribution induced by the dragging effect of recirculation flow in elbow and diverging tube were analyzed, and the lateral secondary flow evolution and its influences on the particle distribution and saltation along horizontal pipe were studied. Further study was focused on the distribution features of gas flow fields, area-averaged secondary flow velocity and particle concentration in horizontal pipe at different inlet velocity. The results show that lateral secondary flow velocity decreases rapidly along the horizontal pipe; local particle concentration can be lowered due to the transportation effect of secondary flow; as the gas inlet velocity equals 4 m/s or less, secondary flow velocity formed in the horizontal pipe is low and the particles deposit gradually; as gas inlet velocity increases to 6 m/s, the cross-sectional particle distribution in horizontal pipe becomes even.

Key words:catalyst particles; gas-solid two-phase flow; elbow; diverging tube; numerical simulation