平原河网地区不同类型农村小管径排水管道数值模拟

农村污水未经处理直接排放导致农村环境受到污染，目前我国大部分农村缺乏完善的污水收集系统，已经铺设排水系统的农村大多存在管网设计与农村排水特点不符、管网建设资金过大等问题。为了解决上述问题，建议在农村建设小管径排水系统进行污水收集，针对平原、丘陵及山区3种类型的农村排水管网的水力学特性进行了探讨，选取其中的管段进行了数值模拟。结果表明：弯管部分压力变化趋势与速度变化趋势相反，弯管处湍动能较大；平原和丘陵的管道设计充满度为0.3~0.9，设计流速为0.7~0.9 m·s⁻¹，山区的管道设计充满度为0.1~0.3，设计流速约为1 m·s⁻¹。上述研究丰富了对小管径排水系统管道内部流态的认识，可为更合理的农村排水管网设计及风险位点的预测提供参考。

Numerical simulation of different types of rural drainage pipeline with small diameter in plain river network area

The discharge of rural sewage without effective treatment leads to the pollution of the rural environment. At present, most rural areas in China lack a complete sewage collection system. In rural areas where sewer systems have been laid, there were some problems such as the design of the pipe network not matching the characteristics of rural drainage, and too high construction funding of sewer systems. In order to solve these problems, the construction of sewer system with small diameter in rural area for sewage collection was proposed. The hydraulic characteristics for the rural sewer systems in the plains, hilly area and mountain area were explored, and the pipe segments were selected for numerical simulation. The results showed that the pressure change trend of part of the elbow was opposite to the velocity change trend, and the turbulent kinetic energy at the elbow was large; the design fullness of pipe in plain and hilly area was 0.3~0.9, and the design flow velocity was 0.7~0.9 m·s−1. The design fullness of pipe in mountain area was 0.1~0.3, and the design flow velocity was about 1 m·s−1. Research above enriched the understanding of the flow patterns of sewer systems with small diameter and provided a reference basis for more reasonable design of rural sewers and prediction of sites where risk will appear.