核电厂高压缸进汽管道高频壳壁振动分析
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摘要
某核电厂机组启机过程中,对高压缸进汽管道和相连仪表管进行了振动加速度和应变的连续监测。通过振动信号时频分析、机组工况参数分析,发现进汽管道及相连仪表管的振动水平与机组状态及主调节阀的开度显著相关,当电功率达到核功率的53%、主调节阀开度达到13.7%时,管道振动水平明显下降。升速及低功率平台下,进汽管道及仪表管以450 Hz以上高频振动为主。经验公式和有限元计算表明,低功率下高压缸进汽管道可能以壳壁振动为主,并伴随有整体弯曲和扭转振动,且模态频率密集。进汽管道振动加速度高达300 g,长期运行下易导致连接支管的振动疲劳失效。增加约束层阻尼是可能的高频壳壁振动缓解措施。
Continuous vibration acceleration and strain measurement of the high-pressure cylinder steam inlet pipes and instrumental pipes are implemented during the start-up process of a Nuclear power plant. Vibration signal analysis and plant condition parameters are analyzed,which shows that direct correlation exists between the vibration level of pipes and the plant condition. Pipe vibration level decrease dramatically when the electric power reaches 53% nuclear power,at which time the main steam control valve's opening ratio arrives at 13.7%. During the speed-raising and low power stage,inlet pipes and instrumental pipes vibrate at frequency above 450 Hz. According to empirical shall wall modal frequency equation and FEM analysis,shell-wall vibration dominates within high frequency domain,at the same time,bending and twisting modes also make contribution. The actual vibration acceleration of the inlet pipe approaches 300 g,which is so high that can easily introduce fatigue failure of branch pipes during long time operation. To reduce the shell-wall mode vibration level,constrained-layer damping can be a potential method.
Continuous vibration acceleration and strain measurement of the high-pressure cylinder steam inlet pipes and instrumental pipes are implemented during the start-up process of a Nuclear power plant. Vibration signal analysis and plant condition parameters are analyzed,which shows that direct correlation exists between the vibration level of pipes and the plant condition. Pipe vibration level decrease dramatically when the electric power reaches 53% nuclear power,at which time the main steam control valve's opening ratio arrives at 13.7%. During the speed-raising and low power stage,inlet pipes and instrumental pipes vibrate at frequency above 450 Hz. According to empirical shall wall modal frequency equation and FEM analysis,shell-wall vibration dominates within high frequency domain,at the same time,bending and twisting modes also make contribution. The actual vibration acceleration of the inlet pipe approaches 300 g,which is so high that can easily introduce fatigue failure of branch pipes during long time operation. To reduce the shell-wall mode vibration level,constrained-layer damping can be a potential method.
引文
[1]薛飞,林磊等.核电厂管道振动评估技术研究[J].大亚湾核电,2011,2:24-28.
[2]J.C.Wachel.Field Investigations of Piping Systems for Vibration-Induced Stresses and Failures[J].The Pressure Vessels and Piping,1982,62:209-221.
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[4]Zakaria N.Ibrahim.Shell Vibration Modes in Thin Wall Pipes Transporting Liquids[J].ASME/JSME 2004 Pressure Vessels and Piping Conference,Emerging Technology in Fluids,Structures,and Fluid Structure Interactions:Volume1,Fluid Dynamics and Fluid Structure Interactions,2004,153-160.
[5]Paidoussis M P,Denise J P.Flutter of thin cylindrical shells conveying fluid[J].Journal of Sound and Vibration,1972(20):9-26.
[6]J.C.Wachel,Scott J.Morton,etc.PIPING VIBRATIONANALYSIS[J].PROCEEDINGS OF THE NINETEENTHTURBOMACHINERY SYMPOSIUM,1999,119-134.
[7]Blevins.Robert D.Formulas for natural frequency and mode shape[M],KRIEGER PUBLISHING COMPANY:2001,291-300.
[8]Stephen M.Price,Donald R.Smith.SOURCES ANDREMEDIES OF HIGH-FREQUENCY PIPING VIBRATIONAND NOISE[J].PROCEEDINGS OF THE 28THTURBOMACHINERY SYMPOSIUM.1999,189-212.
[9]The American Society of Mechanical Engineers.ASMEOM-S/G-2015 Part3 Requirements for Power operational and Initial Start-up Vibration Testing of Nuclear Power Plant Piping Systems[S].New York:The American Society of Mechanical Engineers,2015.
[10]Peter Y.Use of Microcellular Foam Materials in Constrained Layer Damping Treatment[J].Cellular Polymers.200 1(20):p101-114.
[11]郑刚铁,梁鲁等.航天器减振约束阻尼层:中国,200510009838.8[P].2005.09.07.http://cpquery.sipo.gov.cn
[2]J.C.Wachel.Field Investigations of Piping Systems for Vibration-Induced Stresses and Failures[J].The Pressure Vessels and Piping,1982,62:209-221.
[3]Stephen M.Price,Donald R.Smith.SOURCES ANDREMEDIES OF HIGH-FREQUENCY PIPING VIBRATIONAND NOISE[J].PROCEEDINGS OF THE 28THTURBOMACHINERY SYMPOSIUM.1999,189-212.
[4]Zakaria N.Ibrahim.Shell Vibration Modes in Thin Wall Pipes Transporting Liquids[J].ASME/JSME 2004 Pressure Vessels and Piping Conference,Emerging Technology in Fluids,Structures,and Fluid Structure Interactions:Volume1,Fluid Dynamics and Fluid Structure Interactions,2004,153-160.
[5]Paidoussis M P,Denise J P.Flutter of thin cylindrical shells conveying fluid[J].Journal of Sound and Vibration,1972(20):9-26.
[6]J.C.Wachel,Scott J.Morton,etc.PIPING VIBRATIONANALYSIS[J].PROCEEDINGS OF THE NINETEENTHTURBOMACHINERY SYMPOSIUM,1999,119-134.
[7]Blevins.Robert D.Formulas for natural frequency and mode shape[M],KRIEGER PUBLISHING COMPANY:2001,291-300.
[8]Stephen M.Price,Donald R.Smith.SOURCES ANDREMEDIES OF HIGH-FREQUENCY PIPING VIBRATIONAND NOISE[J].PROCEEDINGS OF THE 28THTURBOMACHINERY SYMPOSIUM.1999,189-212.
[9]The American Society of Mechanical Engineers.ASMEOM-S/G-2015 Part3 Requirements for Power operational and Initial Start-up Vibration Testing of Nuclear Power Plant Piping Systems[S].New York:The American Society of Mechanical Engineers,2015.
[10]Peter Y.Use of Microcellular Foam Materials in Constrained Layer Damping Treatment[J].Cellular Polymers.200 1(20):p101-114.
[11]郑刚铁,梁鲁等.航天器减振约束阻尼层:中国,200510009838.8[P].2005.09.07.http://cpquery.sipo.gov.cn