On the analysis of steam turbine and elimination of abnormal vibration

1、 on the analysis of steam turbine and elimination of abnormal vibrationabstract: chinas rapid economic development of chinas power supply to put forward higher requirements. in order to protect residents of urban economic development and stability of electricity to strengthen routine maintenance and

2、 maintenance of steam turbine unit to protect the city power supply has become an important task of power plant maintenance departments. gas turbine power plants as an important component of its abnormal vibration for the entire power generation systems all have important influence on the text on th

3、e abnormal vibration analysis of steam turbine and a brief discussion of exclusion. keywords: steam turbine; abnormal vibration; analysis; exclusion chinas water resources in northern cities than the south because of less thermal power is a major source of urban electricity. power supply is a key ur

4、ban development in order to increase the stability of urban electricity, power plant maintenance departments will regularly carry out overhaul and maintenance of generator sets. steam turbine power generation system as an integral part of the reduction of its failure rate for the entire system has a

5、n important significance. abnormal vibration of steam turbine power plant is more difficult to identify common failures in the cause of the malfunction of a failure, for such a situation, strengthening the abnormal vibration analysis of steam turbine for power generation enterprises provide the basi

6、s for analysis of the maintenance department becomes essential. first, the reasons for abnormal vibration analysis of steam turbine gas turbine power plant was responsible for generating the focus of the mandate. because of its long-running, the key part of the long-term wear and tear and other reas

7、ons, gas turbine failures occur from time to time, which seriously affected the normal operation of generating units. steam turbine steam turbine fault abnormal vibration is more complex in a failure. units tend to be affected due to the vibration of a wide range of effects, as long as the relevant

8、body with the machine of any one device or media will be the vibration causes, such as into the steam parameters, hydrophobic, oil temperature, oil quality, and so on. thus, for the steam turbine analysis of the causes abnormal vibration is particularly important, and only in order to identify the c

9、auses of symptomatic maintenance. leading to abnormal vibration of steam turbine for the various causes of abnormal vibration analysis is the key to maintenance of steam turbine. 2, gas turbine abnormal vibration analysis and exclusion cause abnormal vibration of the main reasons for steam turbine i

10、n the following areas, steam flow excitation, rotor thermal deformation, friction and vibration. for the following three main areas were discussed in detail. (a) the steam flow excited vibration phenomenon and troubleshooting steam flow excitation has two main features: first, money should appear la

11、rger low-frequency components; second vibration increases significantly by the impact of operating parameters, such as load, and the sudden increase should be presented. the reason was mainly due to leaves by the uneven flow of gas to steam flow occurs when the impact of excitation; for large units,

12、 due to a longer last stage, the gas produced in the leaves expanding the end of flow channel disorder may also occur steam flow exciting phenomenon; seal steam flow may also occur exciting phenomenon. exciting for the steam turbine steam flow characteristics, its failure analysis through a long tim

13、e (one year or more) records for each vibration data, together with the unit at full capacity when the data records, to make into a group of curves, the trend of changes observed curve and scope. by changing the rate of lifting loads from 5t / h to 50 / h of the process of change to the water one by

14、 one to observe the curve of change. different load by changing the high-pressure steam turbine governor valve re-tune features, eliminating airflow excitation. simply put, is to determine the unit produces steam flow exciting working state, using changes to reduce the load resulting steam flow rate

15、 and to avoid the load range of exciting ways to prevent steam flow excitation generation. (b) the rotor thermal distortion caused by abnormal vibration unit characteristics, causes and ruled out thermal deformation caused by vibration of the rotor is characterized by a harmonic amplitude increases

16、and the rotor temperature and steam parameters are closely related, mostly occurred in the unit cold after kai machine fixed speed-load stage, this time a gradual increase in rotor temperature, material stress the release of the rotor caused by thermal deformation of a harmonic vibration increases,

17、at the same time may be accompanied by phase change. as the deformation caused by the rotor caused by abnormal vibration unit. rotor permanent bending and bending are two different temporary failure, but the failure mechanism of the same quality with the rotor eccentricity is similar, and therefore

18、will have similar spin and quality of eccentricity excitation force vector. and the centroid deviation difference is that at both ends of shaft bending would produce cone movement, and therefore in the axial direction will have a greater frequency vibrations. in addition, the shaft bending, due to b

19、ending elasticity and rotor imbalance generated by the centrifugal force generated by the phase difference between the two interactions will be offset by the amplitude of shaft speed will progress at a somewhat reduced, that is, to a certain a rotational speed, the shaft of the amplitude will produc

20、e a valley, this relates to unbalanced rotor dynamic characteristics are different. when the bend is less than the role of non-measured, the amplitude of the reduction occurred in the critical speed below; when larger than the imbalance in the amount of bending effect, the amplitude of the reduction

21、 occurred in the critical speed above. for the rotor thermal deformation of the fault handling is the replacement of the abnormal vibration of the rotor to reduce the unit. there is no vibration force units, will not generate abnormal vibration. reposted elsewhere in the paper for free download (c)

22、the vibration characteristics of the friction, causes and ruled out friction and vibration characteristics: first, the rotor thermal bending due to the unbalanced force will generate a new, so the signal frequency vibration frequency remains, but due to the impact and effects of some non-linear fact

23、ors may appear a small amount of sub-frequency, times frequency and high frequency components, and sometimes the waveform there is a cut roof phenomenon. second, friction, vibration amplitude and phase have wave characteristics, wave duration is rather long. serious friction, amplitude and phase are

24、 no longer fluctuations, amplitude increases dramatically. third, the time of deceleration over the critical vibration generally higher than the normal speed up when the big, stopping after the rotor stationary, the measurement of large-axis huang degree than the original value increased significant

25、ly. friction and vibration mechanism: in terms of the turbine rotor, friction can produce jitter whirl phenomena, but the actual impact is mainly the rotor thermal bending. static and dynamic friction points on the circumference of the degree of friction is different, due to heavy friction and later

26、al friction temperature is higher than light side, leading to uneven temperature of the rotor radial cross section, the local heating caused by the rotor thermal bending, resulting in a new role of the unbalanced force to the vibration caused by rotor. third, on the abnormal vibration of turbine fai

27、lure analysis of the reasons for query steps often encountered in the production vagay vibration, shaft vibration of the abnormal changes, abnormal vibration caused by many reasons. according to vibration of the concentration of reasons, to find the main source of vibration when you should pay atten

28、tion to the following several elements: the vibration frequency is 1x, 2x, 1/2x, etc. whether there are changes in the vibration phase and the phase relationship between adjacent bearings. how the stability of vibration (ie with the speed, load, temperature, excitation current, time, and so whether

29、the change is change). for example, the quality of steam turbine rotor imbalance have the following phenomena: l speed and speed when the vibration is proportional to the secondary side, high speed vibration. particularly critical when the vibration over a much larger than in the past. the frequency

30、 of vibration is mainly 1x. vibration phase generally do not change and the adjacent bearing the same phase or reversed-phase occur. vibration stability (in the vibration caused by friction is not the case), and good repeatability. according to vibration characteristics and multifaceted analysis of

31、routine test and maintenance records to find the ultimate cause of the malfunction excluded. in addition there are some defects of the original design unit, should be psychologically prepared and bearing in mind the point of failure, in the event of the first components to check for design flaws. fo

32、r example: east-cylinder 2 exhaust 200mw steam turbine, shaft seal system with 300mw, are low-pressure cylinder at both ends of bearing vibration often around 6,7 silk, are found, such as to maintain the low pressure seal for the steam temperature of 120-130 degrees , the vibration can be reduced to

33、 four basic wire around. plus load vibration to go up, and stability over time should be decreased, if the low pressure seal for the steam temperature above 150 degrees, the vibration also increases. we can see that by analyzing the vibration mainly occurred in the # 4 bearing, mainly due to # 4 bea

34、ring the exhaust hood, the rigid support poor, are more sensitive to temperature, so that # 4 bearing elevation change. dongfang steam turbine 300mw same situation exists, this may be the design of a major common problem. for this reason, its troubleshooting to reinforce # 4 bearing support, measure

35、ment of temperature on the # 4 bearing the specific impact of elevation values in order to find center in advance to reduce # 4 bearing elevation. conclusion: abnormal vibration of steam turbine steam turbine running inevitable failure, but also the more common failures. conducting such troubleshooting, we must not rush to dismantling units, first of all carried out according to fault characteristics of failure analysis to determine the point of failure in to see unit maintenance records to confirm the point of failure of components. if the point of failure for the newly