Hydrodynamics Analysis on Fluid Flow through Spiral Wound Membrane Modules

• Main Authors: Yu-Ling Li, 李雨霖
• Other Authors: Kuo-Lun Tung
• Format: Others
• Language: zh-TW
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/79466064323304805195

碩士 === 中原大學 === 化學工程研究所 === 90 === Effect of spacer design on fluid flow and separation efficiency in a spiral-wound module was conducted using computational fluid dynamic (CFD) technique. The spacer serves both as mechanical stabilizer for channel geometry and turbulence promoters for reducing polarization phenomena near the membrane surface. The turbulence promotion is based upon the flow around the woven threads of the spacer. Previously, several factors affect the pressure drop and mass transfer in a spacer-filled spiral-wound module have been studied based upon flat channel module. However, the curvature of the spacer varies along the spiral flow path. No any effort has been placed on the effects of curvature of the spacer and membrane permeability in the spiral-wound modules on the pressure drop, shear rate and separation efficiency through the curved module. Purposes of this study were emphasized on the effects of curvature of the spacer, fiber arrangement and membrane permeability in the spiral-wound modules on the pressure drop, shear rate and separation efficiency through the modules. Results showed that increase of the curvature of the spacer will result in increases of both the pressure drop and shear rate. On the other hand, the curved spacer in a spiral wound module causes unequal strain rate at inner and outer membrane surfaces. Such unequal shear rates at the inner and outer surfaces would be expected to have an adverse impact on the membrane module performance because of different fouling characteristics for adjacent membrane leaves. Results showed that decreasing of the diameter of outer fiber or increasing of the permeability of inner membrane can improve this adverse impact.