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Numerical Simulation Of Internal Flow And Pressure Fluctuation Characteristics Of Medium Head Francis Turbine

Posted on:2022-04-11Degree:MasterType:Thesis
Country:ChinaCandidate:H SongFull Text:PDF
GTID:2492306551981899Subject:Power Engineering
Abstract/Summary:PDF Full Text Request
The stability of hydraulic turbine has always been a complex problem.Many power stations at home and abroad,due to the pressure pulsation and hydraulic vibration of hydraulic turbine,cause power swing,runner blade cracking,turbine whistling,plant vibration and even unit damage,resulting in huge economic losses.The stability problem is more prominent when the turbine operates under the off design condition,which is a frequent operation state in the multi energy complementary combined power generation system.In this study,numerical study on pressure fluctuation characteristics of Francis turbine in Yangjiawan hydropower station is carried out,which provides reasonable operation area for the stable operation of turbine,and has a good role in promoting the related technical fields.Firstly,construct a three-dimensional water body model of the calculation domain of the flow component of the turbine.Mesh the flow parts of the turbine,including the volute,fixed guide vane,movable guide vane,runner,draft tube and other flow passage water bodies.Secondly,under the three characteristic heads of rated head,145 m water head and maximum water head,the internal flow field of hydraulic turbine under different working conditions is calculated,and the internal flow characteristics of flow passage components under different working conditions are obtained.Finally,the unsteady numerical calculation of different guide vane opening conditions under three characteristic heads of Yangjiawan hydropower station is carried out.A series of monitoring points of flow passage components are set up.The frequency spectrum of pressure fluctuation inside the turbine is analyzed by fast Fourier transform(FFT).The time domain signal can be converted to the frequency domain signal by FFT,and the amplitude of pressure fluctuation with different frequencies can be distinguished,The causes of pressure pulsation of various flow passage components are found out,and the pressure pulsation characteristics of turbine under different working conditions are studied.
Keywords/Search Tags:Yangjiawan Hydropower Station, Hydraulic Turbine, Internal Flow, Pressure Fluctuation, Numerical Calculation
PDF Full Text Request
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