水工闸门垂直水动力计算方法

为了解决水工闸门在启闭过程中垂直水动力的计算方法问题,将垂直水动力分为闸门开启过程中的下吸力和关闭过程中的上托力。首先,在闸门开启过程中,闸门底缘水流的压力能会转化为动能,而在同一开度下流过闸孔的流量又是常量,这就造成了过水断面在闸门底缘处的收缩,流体与闸门底缘分离,当外界补气不充足时,在闸门底缘部位将形成一定真空度,这部分真空度则是造成下吸力的主要原因。其次,在闸门关闭过程中,闸门对水流的阻断以及闸门底缘对水流流向的改变是导致上托力产生的主要原因。最后,该文应用下吸力和上托力的作用原理并结合水流的能量和动量方程提出了闸门启闭过程中下吸力和上托力的计算方法。同时,利用经积石峡水电站试验数据验证后的数值模型进行仿真分析,结果表明:下吸力和上托力计算方法所得结果与仿真结果吻合较好。

CALCULATION METHOD FOR VERTICAL HYDRODYNAMIC FORCE OF HYDRAULIC GATE

In order to calculate the vertical hydrodynamic force of the hydraulic gate during gate opening and closing, the vertical hydrodynamic force is divided into the down-suction force during gate opening and the up-lift force during gate closing. During gate opening, the fluid pressure energy is converted into kinetic energy at the gate bottom edge, while the flow is constant with the same opening, which results in the contraction of the fluid cross-section at the gate bottom edge. Once the supplementary of the air is insufficient, the fluid is separate from the bottom edge of the gate, and then the vacuum forms, which causes the down-suction force. During gate closing, the gate blocks the fluid and changes the flow direction, resulting in the uplift force. Then based on the proposed mechanism of the down-suction force and the up-lift force, this paper employed the fluid energy and momentum equations to deduce the calculation formula of the down-suction force and the up-lift force. Finally the numerical model verified by Ji-Shi-Xia Hydropower test data is utilized to perform a simulation analysis, showing that the simulation results are in good agreement with the calculated down-suction force and up-lift force by the proposed formula.