【摘要】 设计了一种从蜗壳引水通过泄水锥向尾水管内进行轴向射水的结构,实现减弱尾水管内低频压力脉动。对轴向射水和无射水情况下混流式水轮机内部压力脉动进行了模型试验研究。分析了4种部分负荷工况轴向射水和无射水时水轮机内部压力脉动幅值特性和频率特性,研究了轴向射水减弱尾水管低频压力脉动的效果。研究表明,在部分负荷工况下尾水管中存在螺旋涡带并引起尾水管壁处强烈的低频压力脉动,其频率约是1/5转频,该低频压力脉动是引起水轮机不稳定运行的主要原因;实施轴向射水后,在各部分负荷工况尾水管中低频压力脉动幅值都有明显减弱,但涡带频率基本保持不变。轴向射水使涡带向下游移动并对双涡带结构起到抑制作用。更多还原

【Abstract】 A structure was designed to reduce the pressure fluctuation in the draft tube by axial water jet.And the water was obtained from the spiral case through the runner cone into the draft tube.Pressure fluctuation model test of the Francis turbine with and without axial water jet was carried on.And the pressure pulsation amplitude and frequency characteristics with and without axial water jet at four part loads were analyzed.The mitigation effect of pressure fluctuation with axial water jet was studied.It was shown that at part load operation there was a vortex rope in the draft tube and the frequency of the rope was about 1/5 rotating frequency.This vortex rope caused strong low frequency pressure fluctuation.It was the main reason for the unsteady operation of the turbine.With axial water jet the amplitude of the low frequency pressure fluctuation was significantly reduced,but the frequency was not changed obviously.Axial water jet made the vortex move downstream and played an inhibitory effect of the double-vortex.更多还原