弧形闸门前漩涡影响因素研究

Study on influential factors of vortex in front of radial gate

为研究弧形闸门局部开启时引起闸门前发生的吸气漩涡影响因素,取某泄洪闸的其中一孔为研究对象,采用比尺为1∶20的水工模型进行了相关试验研究和理论分析。研究结果表明,闸前吸气漩涡的产生与闸前水深、闸门开度、来流环量以及表面张力和黏性力有关。通过试验观测和理论分析得到,闸前漩涡存在上、下两个临界淹没水深。当闸前水深在临界淹没水深上下限之间时有吸气漩涡发生。弧形闸门局部开启时,开度越大,闸门进水口的宽高比越小,吸气漩涡越强;来流的边界条件引进的环量作用越明显,漩涡越强;当雷诺数Re≥4.4×10~4,韦伯数We≥(104~208)时,可以忽略黏性力和表面张力对试验的影响。最后,通过理论分析建立了只考虑闸门进水口的宽高比和环量数的临界淹没水深公式。

In order to study the influential factors of the air-core vortex occurs in front of the gate caused by partial opening of radial gate,the relevant experimental study and theoretical analysis are made with the 1 ∶ 20 hydraulic model by taking one of the orifices of a sluice gate as the study objective. The study result shows that the occurrence of the air-core vortex in front of the gate is related to the water depth,opening of gate,circulation of inflow,surface tension and viscous force in front of the gate. It is obtained from the experimental observation and theoretical analysis concerned that there are two critical submergence depths（ the upper and the lower） for the vortex in front of the gate. When the water depth in front of the gate is between the upper and lower limits of the two critical submergence depths,the air-core vortex occurs. When the radial gate is partly opened,the larger the opening is,the smaller the aspect ratio of the inlet of the gate is to be and the stronger the air-core vortex is to be,while the more obvious the circulation effect from the boundary condition of the inflow is,the stronger the vortex is to be. When the Reynolds number Re ≥4. 4 × 104 and the Weber number We ≥（ 104 ~ 208）,the effects of viscous force and surface tension on the experiment can be neglected. Finally,a critical submergence depth formula,for which only the aspect ratio of the gate inlet and the number of the circulation are considered,is established through the theoretical analysis concerned.