Abstract Wastewater treatment plants use bubbly flows to promote grit removal from the plant’s influent. Computational fluid dynamics is an attractive tool to virtually prototype grit-chamber designs. This study assesses a two-phase unsteady Reynolds-averaged Euler-Euler (uRANS-EE) approach to predict bubble induced recirculatory flow in a laboratory tank of similar complexity to that expected in a full-scale grit-chamber. Numerical results are validated against a comprehensive experimental data set consisting of a 3D reconstruction of the flow field using a multi-plane stereoscopic particle image velocimetry technique, void fraction profiles using an optical probe and bubble rise-velocities using high-speed video. Depending on the combination of modeling parameters the predicted volumetric fluid flux returning towards the diffuser varied between 60 and 97% of the experimental flux. Predicted rise velocities exceeded measured values by a factor between 1.15 to 1.75 and near bed velocities were underpredicted by upwards of 25%. The principal 3D flow field features were predicted to a sufficient accuracy to support the use of the uRANS-EE approach for numerical grit-chamber prototyping.

中文翻译：

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评估 Euler-Euler 方法以使用 OpenFOAM 预测强 3D 气泡诱导的再循环流

摘要 污水处理厂使用气泡流来促进从工厂进水中去除砂砾。计算流体动力学是一种极具吸引力的工具，可用于模拟沉砂室设计的虚拟原型。本研究评估了两相非稳态雷诺平均欧拉 - 欧拉 (uRANS-EE) 方法，用于预测实验室水箱中气泡引起的再循环流，其复杂性与全尺寸沉砂池中预期的相似。数值结果针对综合实验数据集进行了验证，该数据集包括使用多平面立体粒子图像测速技术对流场进行 3D 重建、使用光学探头的空隙率剖面和使用高速视频的气泡上升速度。根据建模参数的组合，返回到扩散器的预测体积流体通量在实验通量的 60% 到 97% 之间变化。预测的上升速度比测量值高 1.15 到 1.75 倍，近床速度被低估了 25% 以上。主要的 3D 流场特征被预测到足够的精度，以支持使用 uRANS-EE 方法进行数值沉砂室原型设计。