采用叶片与圆盘错流膜过滤黑液中木质素时剪切速度数值模拟研究

Numerical Simulation of the Shear Velocity in Filtering Black Liquor Lignin with Blade and Disk Cross-flow Membrane

动态错流过滤利用叶片或圆盘等旋转附件的高剪切力是确保可持续的高通量进行连续操作的理想物理条件。对比旋转叶片和圆盘在截留黑液中木质素时在膜表面引起的剪切速度,转速800r/min时在膜表面引起的剪切速度明显大于300r/min时的,叶片作为旋转附件比圆盘在膜表面形成的剪切速度更大。与此同时,在转速300r/min、膜的径向距离R>35mm时,旋转叶片在膜表面形成的剪切速度大于旋转圆盘的;膜的径向距离R≤35mm时,旋转圆盘在膜表面形成的剪切速度大于旋转叶片的。

In dynamic cross-flow filtration,the high shear force of rotating attachments such as blades or disks can ensure a sustainable high flux for the continuous operation.In this paper,the shear velocity caused by rotating blades and disks on the film surface when lignin was trapped from black liquor was compared to show that,the shear velocity caused by rotating blades and disks at 800r/min on the film surface is significantly greater than that caused at 300r/min,meanwhile,the blade as a rotating attachment has a higher shear rate than the disk on the membrane surface;and when the radial distance of the film is R>35mm at 300r/min,the shear speed of the rotating blade on the film surface is greater than that of the rotating disk;when the radial distance of the membrane is R≤35mm,the shear velocity formed by the rotating disk on the membrane surface is greater than that of the rotating blade.