城市排水管网明满交替非恒定流数学模型的研究

Study on free-surface-pressurized flow mathematical model for urban drainage networks

该文针对城市排水管网系统存在的明满流共存的计算难点,从一维水流的圣维南方程组的物理意义入手,推导了适用于有压管流的方程组表达形式,提出了当量宽度的概念和计算方法,修正了Preissmann窄缝假定方法中的窄缝宽度公式,将明渠和有压管道两种情况下的方程组写成统一的形式,实现了对明满过渡流的有效数值模拟。通过数学模拟,与经验数据和SWMM模型的对比验证,揭示了当量宽度法的合理性、可行性及其实际应用价值。

The hydraulic calculation of pipe network system, on which open channel flow and pressure conduit flow exist is a difficulty. In this paper, a general form of the Saint Venant equations is derived. A new method ＂the equivalent width＂, which is similar to Preissmann slot assumption in some ways, has been put forward. It is deduced to revise the width formula of Preissmann slot. The model for pressure flow and free surface flow in the drainage networks is built by the uniform governing equations and Preissmann fictitious slot. Through mathematical modeling, comparing with empirical data and SWMM model, the results show that the scheme is feasible and availabe.