泵站进水流速对2种进水方式的表面漩涡特性影响的研究

The Influence of Inlet Flow Rate on Surface Eddy in Pumping Stations

【目的】探究不同进水流速对泵站进水水流流态、漩涡的产生与发展变化规律的影响。【方法】结合泵站实际运行情况,采用NXUG10.0软件构建泵站封闭式进水流道水平进水和开敞式进水池垂直进水2种进水方式的进水物理模型及三维湍流数学模型,采用雷诺N-S方程、VOF模型和非定常的SST k-ω湍流模型。对2种进水方式下不同进水流速的进水流场分布和漩涡的产生、变化及分布规律进行了数值模拟。【结果】在满足泵站进水口临界淹没水深时,2种进水方式下的进水表面漩涡强度随着进水流速的增加逐渐增强,并对2种进水表面出现的漩涡类型与进水流速变化的区间进行了划分;封闭式进水流道水平进水流速在0.217~0.304、0.349~0.448、0.482~0.554、0.575~0.661 m/s时,漩涡类型分别为Ⅰ和Ⅱ型涡、Ⅲ和Ⅳ型涡、Ⅴ型涡、Ⅵ型涡;开敞式垂直进水流速在0.322~0.402、0.484、0.521~0.564m/s时,漩涡类型分别为Ⅲ和Ⅳ型涡、Ⅴ型涡、Ⅵ型涡,开敞式进水池垂直进水的水体中同时产生表面漩涡和水中漩涡;数值计算结果与试验结果基本吻合。【结论】对封闭式进水流道水平进水方式的泵站工程,进水流速不应大于0.349 m/s;对开敞式进水池垂直进水方式的泵站工程,进水流速不应大于0.322 m/s。

【Background and objective】The inflow water velocity controls water flow pattern in pumping stations.Turbulence accompanied by the generated vortices not only reduces pump operation but also causes cavitation,vibration, thereby compromising pump operation. The purpose of this paper is to study the influence of inlet water flow rate on flow pattern, generation and development of vortices in a real pump station.【Method】The NX UG10.0 software was used to construct the physical model for water intake in the pump;three-dimensional turbulence for the pump station, including the closed intake channel, horizontal intake and open intake pool, vertical intake, were described using the Reynolds’ equation, VOF model and unsteady SST k-ω model. The impact of the distribution of influent flow field and generation, change and distribution of the vortices at different influent velocities was simulated for two influent modes.【Result】When the critical submerged depth of the inlet was met, the vortex intensity at the inlet surface under the two inlet modes increased with the increase in the inlet flow rate, and the vortices appeared on the two inlet surfaces and the inlet water. When the horizontal inlet velocity in the closed inlet flow channel was 0.217~0.304, 0.349~0.448, 0.482~0.554, 0.575~0.661 m/s, their associated vortex type was Ⅰ-Ⅱ,Ⅲ-Ⅳ, Ⅴ and Ⅵ, respectively. When the open vertical inlet flow velocity was 0.322~0.402, 0.484, 0.521~0.564 m/s,their associated vortex type was Ⅲ, Ⅳ-Ⅴ and Ⅵ, respectively. Surface vortices were simultaneously generated in the water body of the open inlet pool with vertical water inlet and vortex in the water. The simulation results were consistent with experimental results. 【Conclusion】For pumping stations with closed inlet channel and horizontal inlet method, the inflow velocity should be less than 0.349 m/s for the open inlet pool. For pumping stations with vertical water intake, the influent flow rate should be less than 0.322 m/s.