Influence Of Tailwater Disturbance On Hydraulic Turbine Pressure Fluctuation Characteristics

With the continuous development of the hydraulic turbine design technology and the demand for the electric power and the constant attention to the renewable energy,the capacity of the single machine installed in the hydropower station is increasing,from the 700 thousand KW of the Three Gorges to the present white crane beach 1 million KW.With the increase of the unit,the stability of the machine group has become an industry.The issue of particular concern.When the hydro junction is developed,it is bound to be restricted by geographical location and geological conditions,which will cause the outlet of the tail water to be arranged adjacent to the flood discharge building,which will cause the large fluctuation of the tail water of the hydropower station,which inevitably affects the safety and stability of the unit.This topic mainly studies the influence of the fluctuation law of different tail water on the operation of the turbine unit.Because the existing test bench can not achieve the regular fluctuation of the outlet pressure of the tail water,and with the application of the CFD technology in the hydraulic machinery industry,this subject uses CFD technology to study the fluctuation law of the tail water to the hydraulic turbine.The influence of the line.This topic uses transient simulation to study pressure pulsation.Because the traditional turbulence model is based on the time average of Reynolds,the simulation is the time average.The large eddy simulation is used to study the pressure pulsation.The effect of the amplitude and frequency of the tail water pulsation on the turbine guide vane and the pressure pulsation in the draft tube is mainly studied..The study shows that the amplitude of the undulation of the tail water is 0.1% and 0.2% of the rated water head,because the amplitude of the fluctuation of the tail water is smaller than the head of the rated working condition.The operating operating point of the turbine is basically unchanged.The main frequency of the pressure fluctuation in the guide vane and the tail pipe does not change basically.With the increase of the amplitude of the undulation of the tail water,the guide leaves are increased.The amplitude of pressure pulsation in the draft tube increased,and the frequency of the tail water fluctuated in 10.028 Hz and 50.14 Hz the frequency,which had no influence on the main frequency of the pressure pulsation in the guide vane and the tail pipe,and the amplitude of the pressure fluctuation in the guide vane and the tail pipe would increase under the frequency of 50.14 Hz the frequency of the tail water fluctuation.