Making improvements to feed spacers of spiral-wound membrane (SWM) modules of reverse osmosis (RO) is a necessary step towards a wider application of these modules. This study sets out to evaluate the performance of six commercial feed spacers by comparing their actual velocity profiles and their pressure drop. Velocity profiles are obtained from Particle Image Velocimetry (PIV). Comparing images from PIV with corresponding friction losses revealed that the transition from steady to unsteady flow occurs at the moment when the incline of the friction factor changes from steep to slight. From the two types of spacers used, zigzag spacers showed a better distribution of flow than the cavity spacers did, but at the cost of higher pressure drop. The flow was in a straight line from inlet to outlet with zigzag spacers only at low Reynolds numbers and with cavity spacers for the entire studied range of Reynolds numbers. Additionally, results showed that hydraulic conditions in channels with cavity spacers are mainly affected by geometric characteristics of transverse filaments. The results from this study can be used to understand the effects of spacer geometry on the hydraulic conditions inside the feed channel and as a validation tool for computational modeling.

改进反渗透（RO）螺旋缠绕膜（SWM）模块的进料垫片是迈向这些模块更广泛应用的必要步骤。这项研究着手通过比较六种商用进料垫片的实际速度曲线和压降来评估其性能。速度轮廓是从“粒子图像测速”（PIV）获得的。将来自PIV的图像与相应的摩擦损失进行比较后发现，当摩擦系数的倾斜度从陡峭变化到轻微变化时，就会发生从稳定流到非稳定流的过渡。从所使用的两种类型的间隔件来看，之字形间隔件显示出比空腔间隔件更好的流量分布，但代价是压力降更高。流动是从入口到出口的一条直线，仅在低雷诺数下使用之字形垫片，而在整个研究的雷诺数范围内使用腔垫片。此外，结果表明，带有腔体隔片的通道中的水力条件主要受横向细丝的几何特性影响。这项研究的结果可用于了解垫片几何形状对进料通道内部水力条件的影响，并可作为计算模型的验证工具。