门槽旋涡及壁面压力特性

Vortex and wall pressure characteristics of hydraulic gate slots

平板闸门是水利水电工程中最为常用的一种水工建筑结构。由于水流经过门槽时,流态复杂,易产生空化空蚀破坏,从而影响闸门的安全运行。该文采用SST k-紊流模型对门槽的水力特性进行了研究,主要内容包括:不同来流条件下门槽宽深比对门槽内旋涡负压值和位置、门槽边壁负压值和位置的作用;门槽内旋涡负压与边壁负压的相关性;不同来流条件下,门槽的错距比及宽深比对下游一次和二次分离区负压的影响等。结果表明:来流流速对门槽内旋涡负压、边壁负压和下游分离区负压都有很强的作用;随着宽深比的增加,旋涡中心负压值呈先增加后下降趋势,在宽深比为1.5附近达到最大值;旋涡中心点位置与门槽的宽深比和流速相关,而门槽边壁负压点位置主要与其宽深比相关;门槽中心的旋涡负压与门槽内边壁负压之间有很强的线性相关性,斜率约为0.813;门槽下游斜坡的设置可以有效地改善一次分离区的负压;一次和二次分离区负压同时达到最小的错距比大致为0.03–0.04。

Plate gates are the widespread applied hydraulic structures in water conservancy and hydropower engineering. Cavitation occurs frequently due to the complex flow patterns in the gate slots. In this paper, SST k - ω turbulence model was used to simulate the flow of the gate slot in order to analyze the influence of hydraulic and geometric parameters on the vortex and wall pressure characteristics of the gate slot. The contents of the paper include that the effects of width-depth ratio （W/D） on the pressure and its position of both the vortex center and walls of the gate slot, the pressure correlation between the vortex center and walls, and the effects of W/D and offset-depth ratio （A/D） on the pressure of the first and second separatingzones downstream of the slot. The results show that the approach velocity of the coming flow directly dominates the pressures of the vortex and wall in the gate slot and the pressures of separating zone downstream of the gate slot, and show that with the increase of W/D the negative pressure of the vortex center in the slot increases at first, then decreases, and reaches the top value at about W/D = 1.5, the position of the vortex center was related to both W/D and flow velocity, while the position of negative pressure in the wall was only depend on W/D, the wall pressure value was closely related to that of the vortex center in linearity with the slope of 0.813, and the offset downstream of the slot has the better effect on modification of the pressure of the first separating zone, and when offset-depth ratio △/D value is about 0.03-0.04 the pressures on the first and second separating zones would get the minimum values at the same time.