机械絮凝池内部流场数值模拟和絮凝效果分析

通过对机械絮凝池内不同进水流量和不同桨板转速的流场分别进行数值模拟,计算得到湍动能k和湍动耗散率ε等水力参数,并结合混凝实验分析水流对絮凝效果的影响。结果表明:湍动能k和湍动耗散率ε可以作为评价絮凝是否充分的标准;机械絮凝池最佳水力停留时间为18 min;平均k值为0.00613～0.00212 m2/s2,平均ε值为0.00869～0.00199 m2/s3时,机械絮凝池装置的絮凝效果比较理想。

Numerical simulation and coagulation of flow field for mechanical flocculation

The flow field in the flocculation reaction was numerically modeled by considering different flow rates and different paddle rotating speeds.Combined with the flocculation test,the turbulent kinetic energy k and turbulent dissipation rate ε and other hydraulic parameters that obtained by numerical simulation were used to study the effect of flow on flocculation.The numerical simulation and experimental observation indicate that the turbulent kinetic energy k and turbulent dissipation rate ε can be used as an indicator of flocculation efficiency.The best resident time is 18 min.When the average k value is 0.00613~0.00212 m2/s2,and the average ε value is 0.00869~0.00199 m2/s3,the flocculation efficiency of mechanical flocculation reaction is satisfactory.