Numerical Study on Hydraulic Performance of Composite Spacers Based on Structural Coupling for Spiral-Wound Membrane Elements

Constructing composite structures is an important approach to overcoming the performance bottlenecks of single-type spacers and improving the hydraulic performance of spiral-wound membranes. Based on investigations of column, helical, and perforated spacers, two composite configurations were designed in this study: column-perforated and helical-perforated spacers. Numerical simulations were conducted to analyze the flow field, shear stress, and pressure drop characteristics. The results show that column-perforated spacers eliminate dead zones through perforation-induced microjets, enhance flow uniformity and reduce pressure drop, realizing the synergistic optimization of mass transfer and energy consumption. Helical-perforated spacers improve shear uniformity while retaining the advantage of vortex induction, among which the HP-1 configuration shows the best matching performance and more stable flow. Both composite spacers exhibit excellent performance in dead zone mitigation, shear homogenization, and energy consumption control, providing support for the structural design of spiral-wound membrane elements.