水利枢纽导流工程二维数值模拟

2D numerical simulation of hydro-junction diversion project

水利枢纽工程施工过程中,施工导流是影响工程进度及安全的关键和控制性工程。基于HydroInfo软件采用有限体积方法求解二维浅水方程,建立了二维施工导流模型。模型采用非结构化网格离散计算域,以方便拟合实际导流工程的复杂计算边界。为了验证模型精度,选取了明渠流算例进行数值模拟。通过水位计算值与解析解对比,验证了模型对于具有复杂地形的二维浅水流动的模拟能力。最后,应用该模型对某水利枢纽一期导流工程水流流场进行了模拟研究,对围堰施工前后的流场水力要素进行了对比分析,为复杂条件下水利枢纽施工导流工程设计及施工提供了新的技术措施。修建围堰后,造成围堰上游水位雍高;与之相反,下游水位降低;束窄河床内流速增大。通过分析计算结果,一期围堰能够满足在设计流量下的导流要求,保证基坑的安全。

Construction diversion is a key and control project that affects the progress and safety of the project during the construction of hydraulic project. A 2 D construction diversion model was established based on the 2 D shallow water equations solving by the finite volume method. The unstructured mesh was used to discretize the computational domain in order to fit the computational boundary of the complex practical diversion project. To validate the model, open channel flow was adopted to simulate. By comparing the calculated water level with the analytical solution, the ability of the model for 2 D shallow water flow with complex terrain was verified. Finally, the model was applied to simulate and analyze the flow field of a hydro-junction first stage diversion project. New technical method was provided for the design and construction of hydraulic diversion for big and complex hydro-junction project. The hydraulic parameters of the two flow fields were compared and analyzed. The water level in the channel upstream of the cofferdam increased after the cofferdam was built. On the contrary, the water level in the downstream channel decreased. The velocity in the narrow right-side channel increased. The first stage cofferdam can meet the diversion requirements under the design flow rate and ensure the safety of the foundation pit by analyzing the calculated results.