斜管沉淀池结构参数优化的理论分析

Theory analysis on the configuration parameters' optimization of inclined settling tank

研究认为斜管沉淀池的结构参数(管径d、管长l、倾角θ)和控制参数(表面负荷q、管内流速)影响沉淀效率。分析了进入斜管内絮体的运动轨迹,并借助姚氏特征参数推求设计参数对临界沉速u0的影响情况;同时,对沿斜管内壁下滑的絮团进行受力分析,求取其对结构参数的最低要求。结果表明,u0与表面负荷q成正比,且存在满足絮团下滑条件的最大q;综合考虑絮体沉降和絮团下滑,不同q下存在较优管径d;考虑管长方向上的比临界沉速,斜管长度l可以选择为1.2～1.4m;q相同时,斜管倾角为35°～60°能基本满足絮团下滑的要求。

The configuration parameters of inclined tube package （including diameter, length, and obliquity of inclined tube elements） in sedimentation tank are main factors influencing the sedimentation efficiency of flocs. In this study, the trace curve of floe moving in the inclined tube is calculated. Based on Yao＇s theory formula, the influence of some parameters on critical velocity u0 is analyzed. At the same time, imposed total forces on flocs are studied to find the minimum requirement of parameters. Results show that u0 presents direct proportion to surface load q; there is a max q to fulfill flocs sliding condition. An optimal diameter of inclined tube is needed for high efficiency of floe sedimentation and floes gliding. Considering the specific critical settling velocity along the longitude of the inclined tube, a reasonable length in range of 1.2 to 1.4 m should be convenient. With the same surface load q, to meet floes sliding conditions, the optimal obliquity of inclined tube 0 would be 35° to 60°.