不同开度下平面闸门水动力特性数值分析

Numerical Analysis of Hydrodynamic Force in Different Opening of the Plate Gate

建立不同开度下平面闸门流体计算域,采用VOF模型和标准的k~ε模型进行三维数值模拟,获得闸门周围的流速、压力、湍动能分布变化规律。结果表明：速度场中闸后产生不同大小的漩涡,且随时间的增加向下游逐渐扩散,闸门开度与其所形成的涡径成反比。在一定条件下,闸门开度越小,涡结构直径越大,容易造成闸门下游泥沙的堆积;湍动能随着闸门开度增大而减小,影响闸门底部及下游水流流态,使局部水流出现漩涡和分离;当闸门开度为0.1m时出现最小压力值且上下游压力差最大。使闸门底部过流面积增大,过闸水流流速降低,可以减弱水流对渠道底部冲刷与破坏,且闸门前后所受压力比较平稳,不易遭受空蚀破坏,有利于闸门安全运行。

Established a fluid computational domain in different opening of the plate gate, 3D numerical simulation was. carried out by using VOF model and standard k - εmodel to obtain some distribution regularity of the flow velocity, pressure and turbulence kinetic energy near the gate. The results show that there are different sizes of vortexes in the velocity field, which spread to the downstream and increase with time gradually, the gate opening is inversely proportional to the diameter of its produced vortex after the gate. Under some conditions, the smaller the gate opening is, the greater the diameter of the vortex structure is, it＇s easy to bring about the accumulation of sediment downstream. Turbulent kinetic energy decreases with increase of the gate opening and makes an impact on water flow pattern at the bottom of the gate and the downstream, which result in formation of some vortexes and separation locally in water flow. When the gate opening is 0.1m, the pressure value is the smallest, the upstream and downstream pressure difference is the largest. So appropriate increase of the plate gate opening increases the overflowing area at the bottom of the gate and reduces the gate water flow rate, which can weaken the scour and damage the flow caused to the bottom of channel, meanwhile the pressure before and after the gate is more stable, it is not easy to damage it by cavitation and is conducive to the safe operation of the gate.