基于CFD技术的自动计量弧形闸门流动特性的研究

发布时间：2018-04-24 23:06

本文选题：弧形闸门 + VOF　；参考：《北方工业大学》2014年硕士论文

【摘要】：进口测控一体弧形闸门存在安装条件苛刻、价格昂贵、很难适应泥沙含量大的黄河水灌溉渠系等问题,迫切需要开发适合我国国情的测控一体弧形闸门。掌握过闸水流的水力特性,是成功开发测控一体弧形闸门的基础。本文基于流体动力学(Computational Fluid Dynamics, CFD)理论和Fluent软件模拟技术,对过闸水流的流动特性进行仿真分析。本文采用Pro-E软件建立弧形闸门计算域三维实体模型,应用Fluent的前处理软件Gambit划分网格,借助Fluent软件中的k-ε湍流模型、VOF水气二相流模型以及压力速度耦合方式,对不同闸前水位、闸门开度以及不同渠道结构时的30种工况,进行过闸水流的仿真模拟,得到水流的水气二相图、沿程水位图、速度矢量图以及渠底所受压力曲线等。仿真结果表明：对于目前应用的灌溉水渠,闸前水位在0.25m-1.5m之间保持某固定值不变时,当闸门开度在45°到84°之间逐渐增大,或闸门开度为45°-84°保持某固定值不变,闸前水位由1.5m到0.25m逐渐降低时,在闸门底部产生的涡旋逐渐减小；当闸前水位为1.5m,闸门开度由45°增加到84°时,闸后渠底所受压力的波动范围由22Pa增加到200Pa,闸后水流流速由2.97m/s降低到1.38m/s；当闸门开度为84°,闸前水位由1.5m降低到0.25m时,闸后水流流速由1.38m/s降低到1.29m/s。为减少闸门底部的泥沙堆积,降低过闸水流流速,提高水流流动的稳定性,提出在闸后1.5m处修建长、宽和深度分别为4.5m、1.81m和0.35m的消力池,并将闸后矩形渠长度增加为14.5m的改进方案,计算结果表明：该方案可使闸门底部的泥沙堆积在消力池中,降低泥沙堆积对闸门启闭造成的影响；过闸水流变得稳定,闸前与闸后水流流速分别比改进前降低了4.76%～12.12%与12.41%-59.76%；闸后水流对渠底的冲击力降低了30.15%；闸前与闸后渠底所受压力稳定的区域,分别为闸前0.7m～1.5m,闸后10m-12m,闸后压力波动幅度由改进前的大于1000Pa降低为40Pa,在此范围内安装压力传感器,有利于提高过闸水流流量的测量精度。通过与消力池深度分别为0.25m和0.45m的渠道修建方案进行对比,证明了该改进方案的合理性。采用CFD技术仿真分析过闸水流流态,对弧形闸门安装位置渠道的结构设计、压力传感器安装位置的选择,具有一定的理论指导意义。
[Abstract]:The imported integrated arc gate is difficult to adapt to the Yellow River irrigation canal system with high sediment content because of its harsh installation conditions and high price. Therefore, it is urgent to develop the integrated arc gate suitable for the situation of our country. Mastering the hydraulic characteristics of sluice flow is the foundation of successfully developing the integrated arc gate. Based on the theory of Computational Fluid Dynamics (CFDs) and Fluent software simulation technology, the flow characteristics of sluice flow are simulated and analyzed in this paper. In this paper, the three-dimensional solid model of arc gate is established by using Pro-E software, and the pre-processing software Gambit of Fluent is used to divide the grid. With the help of k- 蔚 turbulence model in Fluent software, the two-phase flow model of water and gas and the coupling mode of pressure and velocity, the water levels in front of different gates are analyzed. The gate opening and 30 working conditions of different channel structures are simulated, and the two phase diagram, water level diagram, velocity vector diagram and pressure curve at the bottom of the channel are obtained. The simulation results show that when the water level in front of sluice remains constant between 0.25m-1.5m and irrigation canal, the opening of gate increases gradually between 45 掳and 84 掳, or the opening of gate keeps a fixed value between 45 掳-84 掳. When the water level in front of the gate decreases from 1.5 m to 0.25 m, the vortex produced at the bottom of the gate decreases gradually, and when the water level in front of the gate is 1.5 m, the opening degree of the gate increases from 45 掳to 84 掳. The fluctuation range of the pressure at the bottom of the sluice is increased from 22Pa to 200Pa. the velocity of flow behind the sluice decreases from 2.97m/s to 1.38m / s, and when the opening of the gate is 84 掳and the water level before the sluice is reduced from 1.5m to 0.25 m, the flow velocity behind the sluice decreases from 1.38m/s to 1.29ms. In order to reduce the sediment accumulation at the bottom of the gate, reduce the flow velocity and improve the stability of the flow, a stilling tank with a length, width and depth of 1.81 m and 0.35 m is constructed at 1.5 m behind the gate, respectively, in order to reduce the sediment accumulation at the bottom of the gate, and to improve the stability of the flow flow. The improved scheme of increasing the length of the rectangular canal behind the gate to 14.5m shows that the scheme can make the sediment at the bottom of the gate accumulate in the stilling pool, reduce the influence of sediment accumulation on the gate opening and closing, and the flow through the gate becomes stable. The velocity of flow before and after the sluice is 4.7612% and 12.41% lower than that before the improvement, respectively; the impact force of the flow behind the sluice on the bottom of the channel is reduced by 30.15%; and the area where the pressure on the bottom of the canal before and after the sluice is stable, The pressure fluctuation amplitude is reduced from greater than 1000Pa to 40 Pa. the pressure sensor is installed in this range, which is helpful to improve the accuracy of flow flow measurement. Compared with the channel construction scheme with the depth of 0.25m and 0.45m respectively, the rationality of the improved scheme is proved. Using CFD technology to simulate and analyze the water flow state of the gate is of theoretical significance to the structural design of the installation channel of the arc gate and the selection of the installation position of the pressure sensor.
【学位授予单位】：北方工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV663.2

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