竖井旋流段流速及压强分布特性

Velocity and Pressure Distribution Characteristics of Vortex Drop Shaft

为了揭示竖井旋流泄洪洞旋流段流速及压强特性,基于Fluent软件,采用RNG k-ε湍流模型和VOF法,对某一竖井旋流泄洪洞进行了数值模拟,并将部分试验结果与模拟结果进行对比。根据模拟结果分析得出:旋流段壁面压强上大下小,空腔压强下大上小。近壁轴向流速沿程增大,在竖井段增率减小,而径向流速极小可忽略。涡室及渐变段旋流总流速在气水界面最大,沿径向平缓减小,随水层变薄其分布渐趋均匀。空腔气体运动无序,气水界面区域流速梯度最大。断面上旋流切向流速分布为组合涡分布,尤其在涡室及渐变段分布特征明显。

In order to reveal the characteristics of the velocity and pressure in the vortex drop shaft,a numerical simulation based on RNG k⁃εturbulence model and VOF method was carried out for a vortex drop shaft spillway,and some test results were compared with simulation results.The results reveal that the upper part of the wall pressure of the swirling flow in vortex drop shaft is larger than that of the lower part,while the cavity pressure is the opposite.The axial velocity near the wall basically increases along the shaft,but the increase rate decreases in the vertical shaft.Additionally,the radial velocity is extremely small and can be ignored.The total flow velocity of vortex chamber and gradi⁃ent section is the largest at the air-water interface,which decreases gently along the radial direction,but its distribution becomes more uni⁃form as the water layer becomes thinner.The cavity gas moves disorderly,with the largest velocity gradient near the air⁃water interface.The tangential velocity distribution of the rotational flow can be regarded as the combined vortex distribution,especially obvious in the vortex chamber and the gradient section.