栅条式微涡除浊技术流场数值模拟

针对铁路隧道施工废水的高精度高效率除浊需求，采用在旋流式澄清池的旋流反应区中加入栅条式微涡发生器的方式来提升设备混凝除浊效率。采用数值模拟手段分析了旋流场内加入栅条前后流场内与混凝有关的特征参数变化，并采用水力实验进行效果验证。结果表明，加入栅条后，混凝流场初始段的湍动动能及湍耗散明显提升，较之空池条件下分别提升19.24%、155.59%。这种变化利于混凝反应初期，药剂的充分分散，增加颗粒的初始碰撞概率。同时，栅条引入后，增加了流场内的涡旋尺度分布范围，利于流场内不同尺度颗粒完成涡旋絮凝。在原水浊度1 000 NTU的条件下，带有栅条的反应器最终上清液出水浊度达37.4 NTU，絮体分形维数可达1.71，较之空池情况下有明显提升。本研究结果可为微涡旋絮凝技术用于隧道废水处理提供参考。

Numerical simulation of flow field in grid micro-vortex for turbidity removal technology

According to requirements of high efficiency turbidity removal in construction wastewater of railway tunnel, spoiler grids were added in the swirling flow field to improve the efficiency of colloidal particle flocculation. Numerical simulations were used to analyze the changes of coagulation-related characteristic parameters in the swirling flow field with grids or not, and hydraulic tests were used to verify the effect. The results showed that the turbulent kinetic energy and turbulent dissipation in the initial section of the swirling flow field were significantly improved by 19.24% and 155.59%, respectively, compared grids with non-grids condition. This change facilitated the full dispersion of the flocculant and increased the initial collision probability of the particles at the early stage of coagulation reaction. Meanwhile, the increase of the vortex average scale range could facilitate the vortex flocculation formation of particles in different scales in the swirling flow field. Under the condition of raw water turbidity of 1000 NTU, the supernatant turbidity of the reactor with grids reached 37.4 NTU and the floc fractal dimension reached 1.71, which was a significant improvement compared with the case without grids. The results of this study can provide references for efficient turbidity removal technology for tunnel wastewater.