主蒸汽管道振动分析
摘要
在电力、石化等大型企业中，存在着大量的高温、高压输汽管道，由于支吊架设计、布置和调整不当，管道常常发生振动，影响管道的使用寿命，对安全生产造成威胁，甚至引起重大事故。
本文在查阅对国内外大量研究资料的基础上，对管道振动原因、常用减振方法、消振措施等进行了深入了解。为了解决八零三电厂2号汽轮机四根主蒸汽导汽管道振动的问题，本文建立了相应的计算模型，并根据计算和实测结果，找出了振动的主要原因，提出了加装偏转支吊架和管道并联的改进措施，完成了改造工作。本文主要工作是：
① 建立导汽管计算模型，并应用ANSYS5.6有限元分析软件，对机组四根导汽管治理前的10阶固有频率和前8阶振型进行计算。
② 实际测量了5种不同蒸汽流量下，导管的频谱和波形。计算和实际测量结果表明：导汽管低频振动以4.3-4.5Hz、9.5Hz频率为主，管系的低阶模态以各导汽管在垂直导管平面和平面内的一阶弯曲、以及绕主汽门处端点与水平段汽机端连线的一阶扭转为主，#3、#4导汽管的振动模态占低阶模态的多数(前八阶模态中的五阶)，除一阶扭转振型，导汽管的其它低阶振动模态中都是进汽缸立管的下端振动变形最大。计算结果和实测结果相吻合。
③ 通过现场勘察，根据计算和测量结果，决定在不改变导汽管原有设计和布置，同时又满足国家标准的前提下，采用加装偏转支吊架、导汽管并联的措施，通过改善导汽管刚度和改变管道固有特性的方法，对该机组四根导汽管振动问题进行了处理。为了保证改造工作顺利完成，用有限元分析软件对改造方案进行了论证，分析了加装偏转支吊架后的管系应力水平和振型，计算结果表明：所提方案能解决导汽管振动问题。
④ 改造完成后的实际测量表明：管道应力符合国标要求，振动峰值从1mm下降到0.2mm，各阶固有频率普遍提高。在6个月的运行过程中，没有发生振动。治理效果良好。
In many big enterprises such as electric power and pentrifaction ones, there are lots of high temperature and pressure pipelines conveying steam. Because of improper design, collocation and adjustment of the supporting and suspending nogs, pipelines often vibrate, which affects natural life, threatens safe production and even leads to grave accident.
On the basis of consulting lots of home and overseas data, this dissertation comprehends profoundly the causes of vibration, the ways of reducing vibration and the measures of eliminating vibration, In NO.803 plat, there are four central stream pipelines, in order to solve their vibration problems, this dissertation brings forward corresponding calculation model. According to results of calculations and experiments, main causes that contribute to vibration are founded, then puts forward improving measures of adding deflexed supporting and suspending nogs and making pipelines shunt-wound, finally completes improvement tasks Following is the main works completed in this thesis:
(1)This thesis sets up a mathematic model of steam pipelines , using ANSYS5.6 limited-unit analyzing software, calculates the ten phase inherent frequency and the foregoing eight phases vibration types of four steam pipelines of the unit before dealt with.
(2)Practical measures the frequency spectrum and wave form at five different kind of steam flux were done. The results of calculation and measures show that the low frequency of steam pipelines vibration fastens on 4.3 to 4.5 Hz and 9.5Hz, the low modes fastens on one-steps curl in vertical plane and its plane of each steam pipeline and one-rotation along with the line connecting the port circling main steam gate and the horizontal port of unit. The modes of #3 and #4 main steam conduits occupy the majority of low steps modes (the five of the first eight phases), except for the first phase rotation vibration, the maximal distortion of other low steps vibration modes are all caused by the vibration of erect pipelines of cylinder. The both results of calculations and experiments are consistent.
(3)By spot reconnaissances, according to the results of calculations and measures, the problem of vibration is solved by adding deflexed supporting and suspending nogs , making pipelines shunt-wound and without changing the previous design and
collocation, which can also measure up nationally. To complete the improving program successfully, the improving project is demonstrated using ANSYS5.6 limited-unit analyzing software, the results of it show that the project put forward can resolve the problem of transmitting steam pipelines.
(4)The practical measures show that: Stress of pipelines accords with national demand and peak value of vibration decreases from 1mm to 0.2mm, whereas the inherent frequency of each phase increased generally. There is no vibration in the course of six months' moving. The effect of improving is all right.
本文在查阅对国内外大量研究资料的基础上，对管道振动原因、常用减振方法、消振措施等进行了深入了解。为了解决八零三电厂2号汽轮机四根主蒸汽导汽管道振动的问题，本文建立了相应的计算模型，并根据计算和实测结果，找出了振动的主要原因，提出了加装偏转支吊架和管道并联的改进措施，完成了改造工作。本文主要工作是：
① 建立导汽管计算模型，并应用ANSYS5.6有限元分析软件，对机组四根导汽管治理前的10阶固有频率和前8阶振型进行计算。
② 实际测量了5种不同蒸汽流量下，导管的频谱和波形。计算和实际测量结果表明：导汽管低频振动以4.3-4.5Hz、9.5Hz频率为主，管系的低阶模态以各导汽管在垂直导管平面和平面内的一阶弯曲、以及绕主汽门处端点与水平段汽机端连线的一阶扭转为主，#3、#4导汽管的振动模态占低阶模态的多数(前八阶模态中的五阶)，除一阶扭转振型，导汽管的其它低阶振动模态中都是进汽缸立管的下端振动变形最大。计算结果和实测结果相吻合。
③ 通过现场勘察，根据计算和测量结果，决定在不改变导汽管原有设计和布置，同时又满足国家标准的前提下，采用加装偏转支吊架、导汽管并联的措施，通过改善导汽管刚度和改变管道固有特性的方法，对该机组四根导汽管振动问题进行了处理。为了保证改造工作顺利完成，用有限元分析软件对改造方案进行了论证，分析了加装偏转支吊架后的管系应力水平和振型，计算结果表明：所提方案能解决导汽管振动问题。
④ 改造完成后的实际测量表明：管道应力符合国标要求，振动峰值从1mm下降到0.2mm，各阶固有频率普遍提高。在6个月的运行过程中，没有发生振动。治理效果良好。
In many big enterprises such as electric power and pentrifaction ones, there are lots of high temperature and pressure pipelines conveying steam. Because of improper design, collocation and adjustment of the supporting and suspending nogs, pipelines often vibrate, which affects natural life, threatens safe production and even leads to grave accident.
On the basis of consulting lots of home and overseas data, this dissertation comprehends profoundly the causes of vibration, the ways of reducing vibration and the measures of eliminating vibration, In NO.803 plat, there are four central stream pipelines, in order to solve their vibration problems, this dissertation brings forward corresponding calculation model. According to results of calculations and experiments, main causes that contribute to vibration are founded, then puts forward improving measures of adding deflexed supporting and suspending nogs and making pipelines shunt-wound, finally completes improvement tasks Following is the main works completed in this thesis:
(1)This thesis sets up a mathematic model of steam pipelines , using ANSYS5.6 limited-unit analyzing software, calculates the ten phase inherent frequency and the foregoing eight phases vibration types of four steam pipelines of the unit before dealt with.
(2)Practical measures the frequency spectrum and wave form at five different kind of steam flux were done. The results of calculation and measures show that the low frequency of steam pipelines vibration fastens on 4.3 to 4.5 Hz and 9.5Hz, the low modes fastens on one-steps curl in vertical plane and its plane of each steam pipeline and one-rotation along with the line connecting the port circling main steam gate and the horizontal port of unit. The modes of #3 and #4 main steam conduits occupy the majority of low steps modes (the five of the first eight phases), except for the first phase rotation vibration, the maximal distortion of other low steps vibration modes are all caused by the vibration of erect pipelines of cylinder. The both results of calculations and experiments are consistent.
(3)By spot reconnaissances, according to the results of calculations and measures, the problem of vibration is solved by adding deflexed supporting and suspending nogs , making pipelines shunt-wound and without changing the previous design and
collocation, which can also measure up nationally. To complete the improving program successfully, the improving project is demonstrated using ANSYS5.6 limited-unit analyzing software, the results of it show that the project put forward can resolve the problem of transmitting steam pipelines.
(4)The practical measures show that: Stress of pipelines accords with national demand and peak value of vibration decreases from 1mm to 0.2mm, whereas the inherent frequency of each phase increased generally. There is no vibration in the course of six months' moving. The effect of improving is all right.
引文
[1] 殷荫龙 陈学源 振动分析的有限元法．地震出版社1985年
[2] 顾晃 汽轮发电机组的振动与平衡 水利出版社出版1988年
[3] DenHartogJ, 《The Balancing of Fle xible Rotors》, A Book 《Air Space and instruments》,N.Y. 1963
[4] 王爱勤 输气管道的减振 应用力学学报 1998．9
[5] Ojalv IU. Proper use of lanczos vectors for large eigenvalue problem. Compur Struct,1989.20.
[6] 徐稼轩，郑铁生结构动力学分析的数值方法，交通大学出版社1993．208-21
[7] 吕泽华，输气管大的分布参数数学模型及工程应用，自动化学报1989．15
[8] 崔孝秉，埋地长输管道热胀内力近似分析力学学报1984．(1)51-60
[9] 郭瑞频 李广信 陈轮 L型直埋供热管道受力规律数值模型 计算结构力学及其应用1996．8(16)
[10] 1Singh, R. and.Sotlel. W. A Review of Compressor lines Pulsation analysis and Muffer Design Research Purdue Compressor Technology conference. 1974
[11] 张阿舟，姚起航 振动控制工程，北京：航空工业出版社，1989．487-494
[12] 胡宗武 工程振动分析基础，上海：上海交通大学出版社，1989．262-291
[13] 张阿舟，诸德超 振动理论与分析，北京航空工业出版社，1996．8-15
[14] 党锡淇 陈守五 孔板消减气流脉动的机理分析，西安交通大学学报1979(2)
[15] 孙隆庆 频谱分析与频谱测量，北京：人民邮电出版社1984
[16] 沈庆根 化工机械故障诊断技术，M杭州：浙江大学出版社1994
[17] 任文敏 韩祖南 提升管结构自由振动的简化计算，振动与冲击1990．(3)：35-39
[18] 屈维德 机械振动手册，北京．机械出版社1995 15-1～24
[19] J Rousslete and G Herrmann.Flutter of Articulated pipes at Finite AmPlitude[J]. Journal of APPlied Mechanics, 1977, 44:154-158.
[20] J S Jensen. Fluid TransPort due to Nonlinear Fluid—Structure interaction[J].Journal of Ffuids and structures, 1997, 11:327-344.
[21] V A Svetlitsky.Vibration of Tubes Conveying Fluids [J] .Journal of the Acoustical society of America, 1977, 62:595-600.
[22] J L Hill and C G Davis. The Effect of Initial Forces on the Hydroelastic Vibration and Stability of Planar Curved Tubes[J].Journal of Applied Mechanics, 1974, 41:355-359.
[23] R W Doll and C D Jr Mote .On the Dynamic Analysis of Curved and Twisted Cylinders Trans Porting Fu lids [J].ASME Journal of pressure Vessel Technology, 1976, 98:143-150.
[24] C DuPuis and J Rousselet.The Equations of Motion of Curved pipes Conveying fluid [J].Journal of Sound and Vbiration, 1992, 153(3):473-489.
[25] A K Misire, P M Paidosis and KSVan. On the Dynamoices of Curved pipes Trans Porting Fluid.part
[26] A K Misra, P M paidoussis and K SVan.On the Dynamics of Curved Pipes TransPorting Fluid. part I:E xtensible Theory [J]-Journtal of Fluids and structures, 1988, 2:211-244.
[27] T C Unny, E L Martin and R N Dubey.Hydroelastic Instability of Uniformly Curved Pipe -luid System[J].Journal of Applied Mechanics, 1970, 37:61-622.
[28] S Chen.Vibration and Stability of a Uniformly Curved Tubes Conveying Fluid[J].Journal of Acoustical Society of America, 1972, 51:223-232.
[29] M P P paidoussis and G X Li. Pipe Conveying Fluid:a Model Dynamical problem[J].Journal of Fluids and Structures, 1993, 7:137-204.
[30] U Lee, C H pak and S C Hong.The Dynamic of a piping System with Internal Unsteady Flow[J] Journal of Sound and Vibration, 1995, 182(2):297-311.
[31] A R Hallell.Velocity of water hammer wave inanElasticplPe[J].ASCEJournal of the Hydraulics Division 1963,89(HY4): 1-12
[32] 李琳、喻立凡，管道及管路系统流固耦合振动问题的研究动态；应用力学学报，1997．9第十四卷，第三期，p40-46页。
[33] 吴勤勤，力学报，1994．24(1)
[34] 梁波，固体力学报，1993，14(2)
[2] 顾晃 汽轮发电机组的振动与平衡 水利出版社出版1988年
[3] DenHartogJ, 《The Balancing of Fle xible Rotors》, A Book 《Air Space and instruments》,N.Y. 1963
[4] 王爱勤 输气管道的减振 应用力学学报 1998．9
[5] Ojalv IU. Proper use of lanczos vectors for large eigenvalue problem. Compur Struct,1989.20.
[6] 徐稼轩，郑铁生结构动力学分析的数值方法，交通大学出版社1993．208-21
[7] 吕泽华，输气管大的分布参数数学模型及工程应用，自动化学报1989．15
[8] 崔孝秉，埋地长输管道热胀内力近似分析力学学报1984．(1)51-60
[9] 郭瑞频 李广信 陈轮 L型直埋供热管道受力规律数值模型 计算结构力学及其应用1996．8(16)
[10] 1Singh, R. and.Sotlel. W. A Review of Compressor lines Pulsation analysis and Muffer Design Research Purdue Compressor Technology conference. 1974
[11] 张阿舟，姚起航 振动控制工程，北京：航空工业出版社，1989．487-494
[12] 胡宗武 工程振动分析基础，上海：上海交通大学出版社，1989．262-291
[13] 张阿舟，诸德超 振动理论与分析，北京航空工业出版社，1996．8-15
[14] 党锡淇 陈守五 孔板消减气流脉动的机理分析，西安交通大学学报1979(2)
[15] 孙隆庆 频谱分析与频谱测量，北京：人民邮电出版社1984
[16] 沈庆根 化工机械故障诊断技术，M杭州：浙江大学出版社1994
[17] 任文敏 韩祖南 提升管结构自由振动的简化计算，振动与冲击1990．(3)：35-39
[18] 屈维德 机械振动手册，北京．机械出版社1995 15-1～24
[19] J Rousslete and G Herrmann.Flutter of Articulated pipes at Finite AmPlitude[J]. Journal of APPlied Mechanics, 1977, 44:154-158.
[20] J S Jensen. Fluid TransPort due to Nonlinear Fluid—Structure interaction[J].Journal of Ffuids and structures, 1997, 11:327-344.
[21] V A Svetlitsky.Vibration of Tubes Conveying Fluids [J] .Journal of the Acoustical society of America, 1977, 62:595-600.
[22] J L Hill and C G Davis. The Effect of Initial Forces on the Hydroelastic Vibration and Stability of Planar Curved Tubes[J].Journal of Applied Mechanics, 1974, 41:355-359.
[23] R W Doll and C D Jr Mote .On the Dynamic Analysis of Curved and Twisted Cylinders Trans Porting Fu lids [J].ASME Journal of pressure Vessel Technology, 1976, 98:143-150.
[24] C DuPuis and J Rousselet.The Equations of Motion of Curved pipes Conveying fluid [J].Journal of Sound and Vbiration, 1992, 153(3):473-489.
[25] A K Misire, P M Paidosis and KSVan. On the Dynamoices of Curved pipes Trans Porting Fluid.part
[26] A K Misra, P M paidoussis and K SVan.On the Dynamics of Curved Pipes TransPorting Fluid. part I:E xtensible Theory [J]-Journtal of Fluids and structures, 1988, 2:211-244.
[27] T C Unny, E L Martin and R N Dubey.Hydroelastic Instability of Uniformly Curved Pipe -luid System[J].Journal of Applied Mechanics, 1970, 37:61-622.
[28] S Chen.Vibration and Stability of a Uniformly Curved Tubes Conveying Fluid[J].Journal of Acoustical Society of America, 1972, 51:223-232.
[29] M P P paidoussis and G X Li. Pipe Conveying Fluid:a Model Dynamical problem[J].Journal of Fluids and Structures, 1993, 7:137-204.
[30] U Lee, C H pak and S C Hong.The Dynamic of a piping System with Internal Unsteady Flow[J] Journal of Sound and Vibration, 1995, 182(2):297-311.
[31] A R Hallell.Velocity of water hammer wave inanElasticplPe[J].ASCEJournal of the Hydraulics Division 1963,89(HY4): 1-12
[32] 李琳、喻立凡，管道及管路系统流固耦合振动问题的研究动态；应用力学学报，1997．9第十四卷，第三期，p40-46页。
[33] 吴勤勤，力学报，1994．24(1)
[34] 梁波，固体力学报，1993，14(2)
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