The rotary energy recovery device (RERD) is widely equipped in desalination to reduce the system energy consumption. In this study, the fluid dynamics and mixing performance of a typical structure RERD and a visualization apparatus of a RERD (V-RERD) had been compared by simulation. The effects of rotating components on fluid dynamics and mixing had been researched. Simulation results indicated that a swirling flow can be observed from flow fields in the device duct. In the RERD case, the swirling flow changed its rotating direction in the center of the duct, while in the V-RERD case, its rotating direction was unchanged. Then, a swirling number Sn was applied to characterize the degree of swirl intensity, and its formation mechanism in RERD had been discussed. In addition, the criterion was adopted to visualize the three-dimensional flow structures and identify vortex structures in the duct. The evolution of vortices in the working process had been investigated. It was found that vortices significantly affected the mixing performance, and the detached vortex could lead to high turbulence and mixing in the duct. Suppressing the vortex shedding may reduce the flow turbulence and gain a lower volumetric mixing rate.

中文翻译：

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回转式能量回收装置管道内流动与混合的模拟研究

旋转式能量回收装置（RERD）广泛应用于海水淡化，以降低系统能耗。在这项研究中，通过模拟比较了典型结构 RERD 和可视化装置 RERD (V-RERD) 的流体动力学和混合性能。研究了旋转部件对流体动力学和混合的影响。仿真结果表明，从装置管道中的流场中可以观察到旋流。在RERD情况下，旋流在管道中心改变了其旋转方向，而在V-RERD情况下，其旋转方向不变。然后，应用旋流数Sn来表征旋流强度，并讨论了其在RERD中的形成机制。此外，该准则用于可视化三维流动结构并识别管道中的涡流结构。研究了工作过程中涡流的演变规律。研究发现，涡流对混合性能有显着影响，分离的涡流会导致管道内产生高湍流和混合。抑制涡流脱落可以减少流动湍流并获得较低的体积混合率。