卷式膜组件中隔板网丝的优化

Optimal Design of Spacer Filament in Spiral-Wound Membrane Modules

利用流体力学的计算方法,以反渗透膜组件中的隔板网丝为研究对象,并在计算的过程中使用了有渗透率壁边界条件的数值模型,系统地研究了d/H值(隔板丝直径d与隔室高度H的比值)的改变对膜通道中的传质以及流体动力学方面的影响。研究结果表明,d/H值的改变对膜表面溶液浓度、水通量以及系统的压力降都有十分重要的影响。随着d/H值的增加,膜表面溶液浓度整体减小,水通量增加,但是当d/H值增大到0.4左右的时候,这两个量变化不再显著。而沿着通道中的压力降随d/H的增加,其增加速度明显变快。因此能量损失在允许的范围内,适当增加网丝直径是有利于增加溶质质量传递的。

Spacer filament in spiral membrane modules were explored by means of Computational Fluid Dynamics(CFD).A numerical model with the boundary condition of the permeation across the membrane was used.The effect of d/H(spacer filament diameter to spacer height radio)on mass transfer and flow in the channels of membrane modules systematically.The results showed the d/H change heavily affected the concentration at the membrane wall,water flux and system pressure drop.The concentration at the membrane wall decreased and water flux increased with d/H.When d/H was 0.4,the concentration at the membrane wall and water flux do not show large difference.However,pressure drop along the channel increases faster and faster with d/H.Therefore,increasing filament diameter is beneficial to the increase of solute mass transfer within the allowable range of energy loss.