温度对辐流式沉淀池水力特性影响的二维数值模拟

2D numerical simulation of the influence of temperature on the hydraulic characteristics in a radial flow sedimentation tank

选取Realizable k-ε湍流模型,在单纯考虑进水与池内水温度差异的条件下,对辐流式沉淀池内冬季与夏季不同时刻异重流的演变规律进行了二维数值模拟。结果表明:由于温度不同,夏季低温水进入池内产生下异重流,而冬季高温水进入池内产生上异重流;冬夏季存在由温差导致的异重流,导致沉淀池内产生较大的回流区;夏季沉淀池内逆时针旋流作用明显,冬季则形成较大的顺时针旋流,从而影响沉淀池的水流流态及污水处理效率。该研究结果可为提高辐流式沉淀池的污水处理效率提供理论支持。

The Realizable k-ε model is used for the 2D simulation of the property of density current by setting a temperature difference between the inlet water and the water in the tank in summer or in winter. The results show that: due to the temperature difference the low-temperature inflow produces the gravity flow in the bottom in summer, while the high-temperature inflow produces the gravity flow on the top in winter;the larger recirculation region in sedimentation tank is produced by the density current with temperature difference,the counterclockwise vortex obviously forms in summer while the clockwise vortex in winter, which influences the water flow property and the efficiency of wastewater treatment of the sedimentation tank. The results provide a theoretical support for improving the efficiency of the radial flow sedimentation tank of sewage treatment.