The difference in the amount of stormwater and sewage in a combined sewer system is significantly large in areas where heavy rainfall is concentrated. This leads to a low water level and slow flow velocity inside the pipes, which causes sedimentation and odor on non-rainy days. A complex cross-section module increases the flow velocity by creating a small waterway inside the pipe for sewage to flow on non-rainy days. While considering Manning’s equation, we applied the principle where the flow velocity is proportional to two-thirds of the power of the hydraulic radius. The flow velocity of a circular pipe with a diameter of 450 mm and the corresponding complex cross-section module was analyzed by applying Manning’s equation and numerical modeling to show the effects of the complex cross-section module. The tractive force was compared based on a lab-scale experiment. When all conditions were identical except for the cross-sectional shape, the average flow velocity of the complex cross-section module was 14% higher while the size of the transported sand grains was up to 0.5 mm larger. This increase in flow velocity can be even higher if the roughness coefficient of aging pipes can be decreased.

中文翻译：

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复合横断面模块降低合流管中沉积物的流动性能分析

在强降雨集中的地区，合流下水道系统的雨水和污水量差异显着。这导致管道内水位低和流速慢，在非雨天会导致沉淀和异味。一个复杂的横截面模块通过在管道内创建一个小水道来增加流速，让污水在非雨天流动。在考虑曼宁方程时，我们应用了流速与水力半径功率的三分之二成正比的原理。应用曼宁方程和数值模型分析了直径为450 mm的圆管和相应的复杂横截面模块的流速，以显示复杂横截面模块的影响。基于实验室规模的实验比较牵引力。当除横截面形状外的所有条件都相同时，复杂横截面模块的平均流速提高了 14%，而输送的砂粒尺寸最大可达 0.5 mm。如果可以降低老化管道的粗糙度系数，流速的增加甚至可以更高。