为研究偏工况下贯流式水轮机叶顶间隙内部流动特征，以某水电站实际运行的水轮机为研究对象，基于SST k-ω湍流模型，研究水轮机在流量为308.538 m3/s，间隙值为10 mm时叶顶间隙内部流场的压力和速度矢量分布以及叶顶间隙内的轴向速度和湍动能分布特性。研究结果表明：在工况3条件下，间隙为10 mm时，在叶片工作面和背面之间大压差的作用下，各个截面均出现了不同程度的流动分离和旋涡运动。从进水边到出水边，湍流强度逐渐降低，叶顶间隙中部受湍流影响较大，沿水流流动方向，各个截面轴向速度分布情况相似，在径向系数r*为0.995~0.997之间时，轴向速度从工作面到背面速度绝对值逐渐增大；在径向系数r*为0.997~1范围内，速度绝对值逐渐降低；在径向系数r*为0.997附近出现了流动分离现象，导致流动状态恶化，湍流能量损失增加，水轮机稳定性下降。

In order to study the internal flow in the tip clearance of a tubular turbine under off design condition,the actual running turbine of a certain hydropower station was taken as the researoh object,based on the SST k-ωturbulence model,when the flow rate is 308.538 m3/s and the clearance value is 10mm, the pressure and velocity vector distribution, axial velocity and turbulent kinetic energy distribution in the tip clearance of the turbine are studied.The results showed that:When the flow rate is 308.538 m3/s and the clearance is 10 mm,different degrees of flow separation and vortex motion occurred in each section because of the action of large pressure difference between the working face and the back side of blade.From the inlet to the outlet,the turbulence intensity decreased gradually,and the middle of tip clearance was greatly affected by turbulence.Along the flow direction,the axial velocity distribution of each section was similar.When the radial coefficient r* was 0.995 to 0.997,the absolute value of the axial velocity from the working face to the back side increased gradually,while the absolute value of the velocity decreased gradually when the radial coefficient r* was 0.997 to 1.At the same time,the flow separation phenomenon appeared near the radial coefficient r* 0.997,which led to the deterioration of flow state,the increase of turbulent energy loss,and the decrease of turbine stability.

TV734.1

国家自然科学基金项目（面上52079118)；四川省（境）外高端人才引进项目(SYZ202073)