穿孔旋流絮凝池的数值模拟研究

发布时间：2019-05-06 09:08

【摘要】：絮凝是净水处理的重要环节之一,絮凝效果的好坏直接关系着后续构筑物的处理效率。絮凝效果的好坏和絮凝池的水力条件有直接的关系,对絮凝池水力条件进行优化改进不仅可以提高絮凝处理效率,而且可以减少混凝剂的投加量,更有利于出水水质的提高。论文主要研究内容是给水处理工程中常用的穿孔旋流絮凝池,论文基于数值模拟方法模拟分析了穿孔旋流絮凝池的污泥斗高度、上层过水孔洞位置和加入网格板对穿孔旋流絮凝池水力条件的影响规律。通过使用湍动能k、湍动能耗散率、涡旋速度梯度G0作为絮凝效果评价指标,探究穿孔旋流絮凝池的最佳水力条件,进而优化穿孔旋流絮凝池的设计参数。通过对穿孔旋流絮凝池的模型进行数值模拟表明:穿孔旋流絮凝池污泥斗高度会影响絮凝处理效果,在保证穿孔旋流絮凝池其他结构尺寸相同的情况下,穿孔旋流絮凝池最优污泥斗高度值随着穿孔旋流絮凝池处理规模的增加而增加,并且变量不同,通过数值模拟得到的穿孔旋流絮凝池污泥斗高度最优值的变化趋势就会不同。在穿孔旋流絮凝池中,将上层过水孔洞设置在最高水位以下10cm的位置处,穿孔旋流絮凝池絮凝效果最好。在穿孔旋流絮凝池内加入网格板后,池内水流的湍动能和湍动能耗散率比不加网格板的穿孔旋流絮凝池高。本文的结果对穿孔旋流絮凝池的设计具有一定的实际指导意义和工程参考价值。
[Abstract]:Flocculation is one of the important links in the treatment of clean water, and the effect of flocculation is directly related to the treatment efficiency of subsequent structures. The effect of flocculation is directly related to the hydraulic condition of flocculation tank. Optimizing the hydraulic condition of flocculation tank can not only improve the efficiency of flocculation treatment, but also reduce the dosage of coagulant, which is more beneficial to the improvement of effluent water quality. The main content of this paper is the perforated swirl flocculation tank commonly used in the water treatment engineering. The sludge bucket height of the perforated swirl flocculation tank is simulated and analyzed based on the numerical simulation method. The influence of the position of the over-water holes in the upper layer and the grid plate on the hydraulic conditions of the perforated swirl flocculation tank. By using turbulent kinetic energy k, turbulent kinetic energy dissipation rate and vortex velocity gradient G0 as the evaluation index of flocculation effect, the optimum hydraulic conditions of perforated swirl flocculation tank are explored, and the design parameters of perforated swirl flocculation tank are optimized. Through the numerical simulation of the model of perforated swirl flocculation tank, it is shown that the sludge bucket height of perforated swirl flocculation tank will affect the flocculation treatment effect, and the other structure size of perforated swirl flocculation tank is the same under the condition that the other structure size of perforated swirl flocculation tank is the same. The optimal sludge bucket height value of perforated swirl flocculation tank increases with the increase of the treatment scale of perforated swirl flocculation tank, and the variation trend of the optimal sludge bucket height obtained by numerical simulation will be different with the increase of treatment scale of perforated swirl flocculating tank, and the variation trend of the optimal value of sludge bucket height of perforated swirl flocculation tank is different. In the perforated swirl flocculation tank, the hole in the upper layer is set below the highest water level at the position of 10cm, and the flocculation effect of the perforated swirl flocculation tank is the best. The turbulent kinetic energy and dissipation rate of turbulent kinetic energy in the perforated swirl flocculation tank are higher than those in the perforated swirl flocculation tank without grid plate. The results of this paper have some practical guiding significance and engineering reference value for the design of perforated swirl flocculation tank.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU991.2

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