湍动能对高效沉淀池絮凝反应的影响分析及试验研究OA

Paddle mixers are widely used in coagulation processes,and by adjusting the placement an-gle of the blades,the water bodies in the sedimentation tank exhibits different flow structures.The mi-xing zone of a high-efficiency sedimentation tank was taken as the analysis object,and three different flow structure mixing modes were designed for the paddle mixers.Turbulent kinetic energy was selected as the evaluation index,and a technical method combining computational fluid dynamics software STAR-CCM+with model experimental research was used to seek the optimal mixing scheme.Among them,the placement angles of the upper and lower blades in scheme 1 were both the+45°,while the placement angles of the lower blades in scheme 2 and the upper blades in scheme 3 were both the-45°,respectively.Based on the comprehensive CFD calculation results and experimental data,the evaluation of water treatment effectiveness of them are consistent,and the turbulent kinetic energy in the rotating domain of the blade is relatively high.The turbulent kinetic energy gradually decreases in the stationary domain,which is far from the blade.The turbulent kinetic energy in the middle water body between the two blades is higher than that in the upper and lower water bodies.Under the same stirring speed,the average velocity of flow and turbulent kinetic energy in scheme 3 are the highest,but scheme 2 has the highest average turbulent kinetic energy value under the same power consumption.The experimental results show that the turbidity removal rate of all schemes reaches its highest value under the treatment capacity of 10 m3/h,while the stirring speed is 60 r/min.The re-moval effect of scheme 2 is significantly better than scheme 1.The removal efficiency of scheme 2 can reach the maximum,79.18％.The research results indicate that it is reasonable to select the turbulent kinetic energy value as the evaluation index to water treatment,either too small or too large turbulent kinetic energy will lead to poor effluent quality.Therefore,designing a reasonable mixing hydraulic component,optimizing the flow structure by controlling turbulent kinetic energy is of great significance for improving flocculation reaction and enhancing removal efficiency.