内置翼片管式静态混合器混合效果的大涡模拟  

Large Eddy Simulation of Mixing Effect in the Tubular Static Mixer with Different Tab Structures

作　　者：张鸿雁[1] 陈晓春[1] 王元[2] 

机构地区：[1]西安建筑科技大学环境与市政工程学院,西安710055 [2]西安交通大学生态环境与现代农业工程中心,西安710049

出　　处：《西安交通大学学报》2005年第7期673-676,共4页Journal of Xi'an Jiaotong University

基　　金：国家自然科学基金重点资助项目(50138020);国家"十五"科技攻关重点资助项目(2004BA901A21).

摘　　要：采用大涡模拟方法对内置翼片管式静态混合器内部的流场和浓度场进行了研究,对比了3种不同结构尺寸的翼片的混合效果和沿混合器轴线的压力损失.数值模拟结果表明小翼片的压力损失最小(ξs=0.52),但混合效果最差;长翼片的混合效果略好于大翼片,但其压力损失仅为大翼片的67%(ξl=2.31,ξb=3.41).同时还发现,在长翼片背后可形成两个逆向旋转的大涡,使混合器中心区域速度梯度增大,剪切作用明显,湍流强度增强.该流场结构能有效地驱使混合器中心高浓度流体流向壁面,从而增大高浓度流体和低浓度流体的接触面积,改善混合条件,故长翼片是一种值得推广使用的翼片结构形式.Flow structure and concentration fields in the tubular static mixer with rows of tabs were investigated by means of large eddy simulation (LES). Flow mixing effect and static pressure distribution along the axis of the tubular static mixer with big tabs, small tabs, and long tabs were compared. The numerical results show that the mixer with small tabs exhibits the lowest resistance(ξs = 0.52) but the mixing effect is the worst. However, the mixer with long tabs has a better mixing effect and also a lower resistance down to 67% of that with big tabs(ξl = 2.31; ξb = 3.41). For the tubular static mixer with long tabs, two anticlockwise vortices are formed behind the tabs, resulting in larger velocity gradient, significant shear stress, and intensified turbulent intensity in the center of mixer. This flow structure induced by long tabs can efficiently drive the high concentration flow to move from center to the region near the wall of the mixer and thus greatly increase the contact area between the high concentration flow and the low concentration flow. It can be concluded that long tabs are good candidates to improve mixing effect in the tubular static mixer.

关 键 词：管式静态混合器 翼片 混合效果 大涡模拟 

分 类 号：TK123[动力工程及工程热物理—工程热物理] TQ051.7[动力工程及工程热物理—热能工程]