水厂清水池的水力特性模拟与结构优化

Hydraulic Characteristic Simulation and Structural Optimization for Clear Water Reservoir of WTP

以某水厂清水池为案例,构建7种不同结构的清水池几何模型进行CFD模拟,对比水力效率和粒子扩散特征。结果表明,清水池前段流态接近混流,后段逐渐均匀,近似平稳推流模式。进口第一个廊道区,导流板背水面和弯道拐角区域易出现回流、大面积循环流等水力状态。增加导流板数目,延长导流板长度,将进出水口设置在进出水廊道宽边中间位置可使清水池更接近理想推流状态。此外,当进水流速为1.2 m/s和2 m/s时,导流板垂直布置的清水池模型因其廊道数更多,比平行布置时的水力效率评价指标值T10/T分别提升23%和13%。CFD模拟显示,实际工程中用于池体稳定的结构柱会显著影响清水池流场流线和消毒剂粒子停留时间,当进水流速为1.2 m/s和2 m/s时,结构柱的存在会使T10/T分别提升31%和38%,但同时会引起流线的纵向扰动,是影响清水池水力条件的重要因素。研究成果可以为水厂清水池的设计优化提供参考借鉴。

Characteristic of flow patterns and particle diffusion of clear water reservoir with 7 different structures was studied by numerical modeling and CFD simulation.The results indicated that the flow pattern in the first section of clear water reservoir was close to the mixed flow,and the flow in the rear section was gradually uniform,which was approximately a plug flow pattern.At the entrance of the first corridor,back-water surface of guide plate and corner area of the curve were prone to backflow,large area of circulating flow and other hydraulic states.Increasing the number of guide plates,extending the length of guide plates,and setting the inlet and outlet in the center of the corridor could effectively improve hydraulic efficiency of clear water reservoir.Due to its more corridors,vertical arrangement of guide plates had higher hydraulic efficiency than parallel arrangement,and its hydraulic efficiency index T10/T value increased by 23%and 13%when the inflow velocity was 1.2 m/s and 2 m/s,respectively.CFD simulation showed that structural columns used for pool stability would significantly affect flow streamline and disinfectant particle residence time,and increased T10/T val-ue by 31%and 38%when the inflow velocity was 1.2 m/s and 2 m/s,respectively.Meanwhile,structural column could cause longitudinal disturbances and it was one of important factors affect the hydraulic efficiency of clear water reservoir.The results can provide reference for the design and optimization of clear water reservoir in water treatment plants(WTP).