叶顶汽封径向和轴向间隙对汽轮机泄漏量及主轴位移的影响
|
摘要
通过对某化工厂汽轮机的叶顶汽封和主轴轴位移故障的分析,发现当漏气量增加到一定程度后会加快推力轴承的磨损,从而引起汽轮机轴位移逐渐增加,这表明汽封的损坏不仅引起泄漏增加还会导致主轴位移增加。采用FLUENT软件对叶顶汽封的流场进行数值模拟,研究汽轮机叶顶汽封的径向间隙和轴向间隙对汽轮机泄漏量及汽轮机主轴位移的影响,提出合理的工作间隙。研究发现:汽轮机叶顶汽封径向间隙是影响泄漏的重要因素,径向间隙增大将导致蒸汽泄漏量增大,汽轮机轴向推力增加,从而导致主轴位移增加;在总长度一定时,轴向间隙值对蒸汽泄漏量没有明显影响,但增加轴向间隙可以使进入汽封的蒸汽压力更加稳定。考虑到叶顶汽封的装配和热膨胀问题,对所研究的叶顶汽封提出了径向间隙为0.65 mm,轴向间隙为3.5 mm的修复方案,通过实践证明该方案现场修复是成功的。
Through the analysis of the displacement faults of the top seal and the spindle of a steam turbine in a chemical plant,it is found that the wear of thrust bearings will be accelerated when the air leakage increases to a certain extent and the shaft displacement of the steam turbine will gradually increase,which indicates that the damage of the seal not only causes the increase of leakage,but also causes the increase of the spindle displacement.The flow field of the top seal was simulated by using the FLUENT software,the influence of radial and axial clearance of the top seal on the leakage and the displacement of the main shaft of the turbine was studied,and the reasonable working clearance was put forward.The results show that the radial clearance of the steam seal on the top of the blade is an important factor affecting the leakage,and the increase of the radial clearance will lead to the increase of the steam leakage and the increase of the axial thrust of the steam turbine,which will lead to the increase of the spindle displacement.When the total length is fixed,the axial clearance has no obvious effect on the steam leakage,however the increase of the axial clearance can make the steam pressure to the seal more stable.Considering the assembly and thermal expansion of the blade top steam seal,a repair scheme with radial clearance of 0.65 mm and axial clearance of 3.5 mm was put forward for the studied blade top steam seal.Practice proves that the repair scheme is successful in site repair.
Through the analysis of the displacement faults of the top seal and the spindle of a steam turbine in a chemical plant,it is found that the wear of thrust bearings will be accelerated when the air leakage increases to a certain extent and the shaft displacement of the steam turbine will gradually increase,which indicates that the damage of the seal not only causes the increase of leakage,but also causes the increase of the spindle displacement.The flow field of the top seal was simulated by using the FLUENT software,the influence of radial and axial clearance of the top seal on the leakage and the displacement of the main shaft of the turbine was studied,and the reasonable working clearance was put forward.The results show that the radial clearance of the steam seal on the top of the blade is an important factor affecting the leakage,and the increase of the radial clearance will lead to the increase of the steam leakage and the increase of the axial thrust of the steam turbine,which will lead to the increase of the spindle displacement.When the total length is fixed,the axial clearance has no obvious effect on the steam leakage,however the increase of the axial clearance can make the steam pressure to the seal more stable.Considering the assembly and thermal expansion of the blade top steam seal,a repair scheme with radial clearance of 0.65 mm and axial clearance of 3.5 mm was put forward for the studied blade top steam seal.Practice proves that the repair scheme is successful in site repair.
引文
[1]MEYER C A,LOWRIE J A.The leakage thru straight and slant labyrinths and honeycomb seals[J].Engineering for Gas Turbines and Power,1975,97(4):495-501.
[2]MOORE J J.Three-dimensional CFD rotor-dynamic analysis of gas labyrinth seals[J].Vibration and Acoustics,2003,125(4):427-433.
[3]WITTING S L K,DORR L,KIM S.Scaling effects on leakage losses in labyrinth seals[J].Applied Intelligence,1983,31(3):225-233.
[4]李志刚,李军,丰镇平.迷宫密封泄漏特性影响因素的研究[J].西安交通大学学报,2010,44(3):16-20.LI Z G,LI J,FENG Z P.Effects of gap pressure ratio and rotational speed on discharge behavior of labyrinth seal[J].Journal of Xi’an Jiaotong University,2010,44(3):16-20.
[5]李志刚,郎骥,李军,等.迷宫密封泄漏特性的试验研究[J].西安交通大学学报,2011,45(3):48-52.LI Z G,LANG J,LI J,et al.Experiment on leakage flow characteristics of labyrinth seal[J].Journal of Xi’an Jiaotong University,2011,45(3):48-52.
[6]陈尧兴,李志刚,李军.非均匀进汽时迷宫密封汽流激振动力特性的研究[J].西安交通大学学报,2017,51(9):145-152.CHEN Y X,LI Z G,LI J.Fluid excited rotordynamic characteristics of labyrinth seal during non-uniform inlet flowing[J].Journal of Xi’an Jiaotong University,2017,51(9):145-152.
[7]丁学俊,杨彦磊,肖国俊,等.迷宫密封流场与泄漏特性研究[J].流体机械,2006,34(4):14-18.DING X J,YANG Y L,XIAO G J,et al.Investigation of flow and leakage in labyrinth seal[J].Fluid Machinery,2006,34(4):14-18.
[8]李耕耘.汽轮机内迷宫密封的动力特性计算与分析[D].北京:清华大学,2015.
[9]GAMAL A J M,VANCE J M.Labyrinth seal leakage tests:tooth profile,tooth thickness,and eccentricity effects[J].Engineering for Gas Turbines and Power,2007,130(1):1127-1138.
[10]LIN Z,WANG X,YUAN X,et al.Investigation and improvement of the staggered labyrinth seal[J].Chinese Journal of Mechanical Engineering,2015,28(2):402-408.
[11]周国宇,王旭东,林智荣,等.高低齿迷宫密封泄漏量实验及计算分析[J].工程热物理学报,2015,36(9):1889-1893.ZHOU G Y,WANG X D,LIN Z R,et al.Preliminary analysis to the leakage of the staggered labyrinth seal based on experiment and simulation[J].Journal of Engineering Thermophysics,2015,36(9):1889-1893.
[12]KONG X,LIU G,LIU Y,et al.Experimental testing for the influences of rotation and tip clearance on the labyrinth seal in a compressor stator well[J].Aerospace Science and Technology,2017,71:556-567.
[13]PAOLILLO R,MOORE S,CLOUD D,et al.Impact of rotational speed on the discharge characteristic of stepped labyrinth seals[C]//Proceedings of ASME Turbo Expo 2007:Power for Land,Sea,and Air.Montreal:American Society of Mechanical Engineers,2007:1291-1298.
[14]宋占宽,曾永忠,刘小兵,等.基于CFD偏置迷宫密封泄漏特性研究[J].机床与液压,2018,46(11):150-153.SONG Z K,ZENG Y Z,LIU X B,et al.Study on leakage of eccentric labyrinth seal on based CFD tools[J].Machine Tool&Hydraulics,2018,46(11):150-153.
[15]顾永泉.机械密封实用技术[M].北京:北京机械工业出版社,2015.
[16]蔡仁良,顾伯勤,宋鹏云.过程装备密封技术[M].北京:化学工业出版社,2010.
[17]康松,杨建明.汽轮机原理[M].北京:中国电力出版社,2012.
[2]MOORE J J.Three-dimensional CFD rotor-dynamic analysis of gas labyrinth seals[J].Vibration and Acoustics,2003,125(4):427-433.
[3]WITTING S L K,DORR L,KIM S.Scaling effects on leakage losses in labyrinth seals[J].Applied Intelligence,1983,31(3):225-233.
[4]李志刚,李军,丰镇平.迷宫密封泄漏特性影响因素的研究[J].西安交通大学学报,2010,44(3):16-20.LI Z G,LI J,FENG Z P.Effects of gap pressure ratio and rotational speed on discharge behavior of labyrinth seal[J].Journal of Xi’an Jiaotong University,2010,44(3):16-20.
[5]李志刚,郎骥,李军,等.迷宫密封泄漏特性的试验研究[J].西安交通大学学报,2011,45(3):48-52.LI Z G,LANG J,LI J,et al.Experiment on leakage flow characteristics of labyrinth seal[J].Journal of Xi’an Jiaotong University,2011,45(3):48-52.
[6]陈尧兴,李志刚,李军.非均匀进汽时迷宫密封汽流激振动力特性的研究[J].西安交通大学学报,2017,51(9):145-152.CHEN Y X,LI Z G,LI J.Fluid excited rotordynamic characteristics of labyrinth seal during non-uniform inlet flowing[J].Journal of Xi’an Jiaotong University,2017,51(9):145-152.
[7]丁学俊,杨彦磊,肖国俊,等.迷宫密封流场与泄漏特性研究[J].流体机械,2006,34(4):14-18.DING X J,YANG Y L,XIAO G J,et al.Investigation of flow and leakage in labyrinth seal[J].Fluid Machinery,2006,34(4):14-18.
[8]李耕耘.汽轮机内迷宫密封的动力特性计算与分析[D].北京:清华大学,2015.
[9]GAMAL A J M,VANCE J M.Labyrinth seal leakage tests:tooth profile,tooth thickness,and eccentricity effects[J].Engineering for Gas Turbines and Power,2007,130(1):1127-1138.
[10]LIN Z,WANG X,YUAN X,et al.Investigation and improvement of the staggered labyrinth seal[J].Chinese Journal of Mechanical Engineering,2015,28(2):402-408.
[11]周国宇,王旭东,林智荣,等.高低齿迷宫密封泄漏量实验及计算分析[J].工程热物理学报,2015,36(9):1889-1893.ZHOU G Y,WANG X D,LIN Z R,et al.Preliminary analysis to the leakage of the staggered labyrinth seal based on experiment and simulation[J].Journal of Engineering Thermophysics,2015,36(9):1889-1893.
[12]KONG X,LIU G,LIU Y,et al.Experimental testing for the influences of rotation and tip clearance on the labyrinth seal in a compressor stator well[J].Aerospace Science and Technology,2017,71:556-567.
[13]PAOLILLO R,MOORE S,CLOUD D,et al.Impact of rotational speed on the discharge characteristic of stepped labyrinth seals[C]//Proceedings of ASME Turbo Expo 2007:Power for Land,Sea,and Air.Montreal:American Society of Mechanical Engineers,2007:1291-1298.
[14]宋占宽,曾永忠,刘小兵,等.基于CFD偏置迷宫密封泄漏特性研究[J].机床与液压,2018,46(11):150-153.SONG Z K,ZENG Y Z,LIU X B,et al.Study on leakage of eccentric labyrinth seal on based CFD tools[J].Machine Tool&Hydraulics,2018,46(11):150-153.
[15]顾永泉.机械密封实用技术[M].北京:北京机械工业出版社,2015.
[16]蔡仁良,顾伯勤,宋鹏云.过程装备密封技术[M].北京:化学工业出版社,2010.
[17]康松,杨建明.汽轮机原理[M].北京:中国电力出版社,2012.