洞内曲线阶梯连接段水流压强特性数值计算

Numerical simulation on the pressure characteristics of the flow over curve-floor stepped tunnel

该文采用水气两相流Mixture模型,结合Realizable k-紊流模型对曲线阶梯连接段水流进行了三维紊流数值计算,得到了阶梯底板及边墙的压强分布规律。计算结果表明,曲线阶梯底板水平面压强沿步长方向呈倒"S"曲线分布,底板竖直面呈"C"字型分布,计算值和试验值变化规律和数值吻合。在斜面阶梯段,底板压强在横向上分布均匀;在水平阶梯段,底板压强在横向上分布不均匀,每个水平阶梯0.8倍步长处横向上存在两个高压中心。在阶梯凹角处存在负压,第二个水平阶梯(16#阶梯)负压值最大。每个阶梯边墙上存在一个高压中心和一个低压中心,高压中心在0.8倍阶梯步长底板处,低压中心在阶梯凹角的漩涡中心位置。由于进口流速大,阶梯前设置突扩突跌掺气设施,阶梯布置不同,该阶梯消能工的压强特性存在三维特性。

The air-water two-phase flow Mixture model and the Realizable κ-ε turbulence model is applied to simulate the flow over curve-floor stepped tunnel, and the pressure distributions of the step＇s bottom and side wall are obtained. The simulation results show that the pressure distribution along the length direction of the step＇s horizontal plane is inverted ＂S＂ curve and pressure distribution at vertical plane showed a ＂C＂ shape change. The variation and value of calculated and experimental are very close. Pressure in the transverse direction has a uniform distribution at the inclined step segment, but notuniform at the horizontal step segment, there are two high pressure centers at each horizontal step＇s 0.8 times length of the step. There exists negative pressure at concave comer of the step, the maximum negative value is at the second level step （16# step）. There are a high-pressure center and a low-pressure center at each step side wall, the high-pressure center is at the bottom and 0.8 times length of the step and the low-pressure center is at the center of the swirl. The pressure of this stepped energy dissipater has three-dimensional characteristics because of the high inlet velocity, the aerated setting with sudden enlargement and sudden falling and the different step arrangement.