In this study, a perforated baffle design is proposed to improve mixing in contact tanks. Turbulent flow through the perforated baffle is studied at the perforation hole scale. The contribution of jets emerging from the perforations to the mixing process is evaluated in terms of standard mixing indexes for various perforation parameters, such as the solidity ratio and hole diameter. Based on numerical simulation results, the two sets of perforated baffles that yielded the highest performance were manufactured from polycarbonate and tracer studies were conducted on a laboratory model. Comparison of numerical and experimental results demonstrates that the numerical model developed is reliable in simulating the flow through the perforated baffles and the associated mixing level in the contact tank. Numerical simulations indicate that the jet flow structure through the perforated baffle penetrates to the recirculation zones in the neighboring chambers and turns the dead zones into active mixing zones. Furthermore, large scale turbulent eddies shed by the perforations contribute to the mixing process in the chambers of the tank. With the use of the perforated baffle design, it is shown that the hydraulic efficiency of the tank can be improved from average to superior according to the baffling factor, and the associated mixing in the proposed design can be improved by 31% according to the Morrill index.

中文翻译：

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用于改善接触罐混合的穿孔挡板设计

在这项研究中，提出了一种穿孔挡板设计来改善接触罐中的混合。在穿孔尺度上研究通过穿孔挡板的湍流。射孔射流对混合过程的贡献是根据各种射孔参数的标准混合指数来评估的，例如密实度和孔径。根据数值模拟结果，性能最高的两组穿孔挡板由聚碳酸酯制成，并在实验室模型上进行了示踪研究。数值和实验结果的比较表明，所开发的数值模型在模拟通过多孔挡板的流动和接触罐中相关的混合水平方面是可靠的。数值模拟表明，射流结构通过穿孔挡板穿透到相邻室中的再循环区，并将死区变成活跃的混合区。此外，由穿孔产生的大规模湍流涡流有助于罐室中的混合过程。使用穿孔挡板设计，表明根据挡板系数可以将罐的水力效率从平均提高到卓越，并且根据 Morrill 的研究，所提出的设计中的相关混合可以提高 31%指数。由穿孔产生的大规模湍流涡流有助于罐室中的混合过程。使用穿孔挡板设计，表明根据挡板系数可以将罐的水力效率从平均提高到卓越，并且根据 Morrill 的研究，所提出的设计中的相关混合可以提高 31%指数。穿孔产生的大规模湍流涡流有助于罐室中的混合过程。使用穿孔挡板设计，表明根据挡板系数可以将罐的水力效率从平均提高到卓越，并且根据 Morrill 的研究，所提出的设计中的相关混合可以提高 31%指数。