长距离无压引水隧洞水气两相流数值模拟

建立了长距离无压引水隧洞水气两相流耦合VOF法的三维标准k-e紊流模型，近壁面采用考虑糙率影响的壁面函数，采用PISO(Pressure-Implicit with Splitting of Operators)算法求解非稳态的水气两相流流场。应用计算流体力学CFD(Computational Fluid Dynamics)软件STAR-CD对某长距离无压引水隧洞水气两相流进行了模拟。结果表明长距离无压引水隧洞在隧洞进口处出现水流扰动区，在主支洞交汇处出现水流漩涡区，在隧洞出口处出现水流突变区；分析了隧洞沿程过水面积及气流量的变化规律，结果表明01支洞和02支洞补气不明显，03支洞补气明显；对某水库放水兼放空洞水深实测数据进行了验证对比，模拟结果与实验基本吻合。

Numerical simulation of water-air two-phase flow in long distance free flow tunnel

A three-dimensional standard k-e model coupled with the Volume of Fluid (VOF) method was established; the method of Wall functions which consider the impact on the walls of rough was used near the wall, and the PLIC procedure was employed to reconstruct the interface. The simulations were performed by the fluid dynamics code STAR-CD. A long distance free flow diversion tunnel was used as a case. According to the result of numerical simulation, water flow disturbance zone appeared in the tunnel inlet, vortex zone appeared in the crossing, and water flow mutation zone appeared in the tunnel outlet. The law of cross section area and the air flow along the way was analyzed. The results showed that the effect of air supply was not obvious on 01branch tunnel and 02 branch tunnel, but obvious on 03 branch tunnel. The simulated results were well in agreement with the experimental work.