气泡尺寸对一体化污水处理系统曝气过程中氧传质效率的影响机制研究

本研究通过计算流体动力学-群体平衡模型（CFD-PBM）耦合氧传质模型，揭示了初始气泡直径（d0=1–4 mm）对好氧池氧传质效率的非线性影响规律。研究发现d0=2 mm时兼具高氧传质系数（kLa=6×10?3 s?1）与溶解氧（DO）分布均匀性，为小型一体化污水处理系统（IWTS）的曝气优化提供了关键设计参数。

　　

Effect of bubble size on dissolved oxygen distribution

气泡尺寸对溶解氧分布的影响

Fig. 6(a) shows the DO distribution at 20 s under different d₀, revealing significant variations. As shown in Fig. 6(b) and (c), at d₀ = 1 mm, bubbles are more strongly affected by turbulence and viscosity, tending to aggregate along the central axis and form a narrow, dense bubble column. This restricts the disturbance range and circulation zone, leading to a more concentrated DO distribution with steeper spatial gradients. As a result, oxygen mainly concentrated along the bubble rising path.

图6(a)展示了不同初始气泡直径（d₀）条件下20秒时的溶解氧（DO）分布情况，呈现出显著差异。当d₀=1 mm时，气泡受湍流和黏性作用更明显，易沿中心轴聚集形成狭窄而密集的气泡柱。这限制了扰动范围和循环区域，导致DO分布高度集中且空间梯度陡峭，氧气主要富集在气泡上升路径附近。

Conclusion

结论

This study integrates CFD-PBM with an oxygen transfer model to systematically examine the impact of d₀ (1–4 mm) on oxygen transfer characteristics in an aerobic tank in a small-scale IWTS. Results reveal that DO distribution exhibits a clear dependence on d₀. And the effect of d₀ on k_L is considerably greater than that of the flow field. Specifically, a d₀ of 2 mm exhibited the best performance, with a high k_La (6×10^?3 s^?1), low aggregation probability (reduced by 17 %), and a more uniform

本研究通过耦合CFD-PBM与氧传质模型，系统分析了d₀（1–4 mm）对小型一体化污水处理系统（IWTS）好氧池氧传质特性的影响。结果表明：溶解氧（DO）分布明显依赖于d₀，且d₀对液相传质系数（k_L）的影响远大于流场作用。具体而言，d₀=2 mm时表现最佳，不仅具有高氧传质系数（k_La=6×10^?3 s^?1）和低气泡聚合概率（降低17%），还能实现更均匀的DO分布。