| The FlumeGate that our country has imported from abroad causes several problems during using the Gate, such as high installation requirement, very expensive and difficult to adapt to Yellow River water irrigation canal system with high silt content, so it is imperative to self develop Automatic Calculation Flow Radial Gate that suit to China’s national conditions. To master the hydraulic characteristics of water that flows though the gate is the basis to successfully develop Automatic Calculation Flow Radial Gate. We simulate and analysis the flow state of water that flow though radial gate based on Computational Fluid Dynamics theory and Fluent software simulation technology.The Radial Gate calculation domain three-dimensional entity model has been built by Pro-E, grid division has been finished by Gambit that is the preprocessing software of Fluent, then water that flow though the gate that include30kinds of conditions under different water level before the gate, different opening angle of the gate and different channel structure has been simulated by k-e turbulence model, VOF water and air two-phase flow model and pressure and velocity coupled manner in the Fluent software in order to get water and air two-phase diagram、 velocity vector diagram and canal bottom pressure curve and so on.According to simulation results, it is concluded that for the irrigation canal that is current in use, when the water level before the gate is keeping fixed value between0.25m and1.5m, while opening angle of the gate is gradually increasing from45°to84°, or when the opening angle of the gate is keeping fixed value between45°and84°, while water level before the gate is gradually decreasing from1.5m to0.25m, the vortex that generates under the gate is gradually decreasing. When the water level before the gate is1.5m, and the opening angle of the gate increases from45°to84°, the range of pressure surges after the gate has been increased from22Pa to200Pa, the flow velocity after the gate has been reduced from2.97m/s to1.38m/s. When the opening angle of the gate is84°, the water level before the gate has been reduced from1.5m to0.25m, the flow velocity after the gate has been reduced from1.38m/s to1.29m/s.In order to reduce the quantity of sediment under the gate, decrease flow rate of water that flow though radial gate and improve the stability of the water flow, the improvement project has been proposed that the stilling pool with4.5m length,1.81m width and0.35m deep has been built at a distance of1.5m from the gate and the length of rectangle channel after the gate has been increased to14.5m, the calculating results showed that after this project has been adopted, the sediment under the gate has been piled up in the stilling pool to reduced the effects of sediment accumulation on the opening and closing of the gate, water flows more smooth and the reduction of flow velocity before and after the gate are4.76%～12.12%and12.12%～12.41%respectively, the power of water impacts the bottom of the channel was reduced by30.15%, and the range of pressure surges at lower level at the bottom of gate installation area channel in the rectangle channel are0.7m～1.5m before the gate and10m～12m after the gate respectively, the range of pressure surges after the gate has been reduced from exceeded1000Pa to40Pa, installing pressure sensor in this range could increase measurement precision of flow rate. And the rationality of this improvement project has been proved by contrasting other channel building project with different stilling pool depth such as0.25m and0.45m.Simulating and analyzing flow state of water that flows though radial gate has definite theoretical direction sense to design the channel structure of radial gate installed position and to choose pressure sensor installation site. |
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