This week’s technical discussion post (Analysis of Abnormal Vibration of Steam Turbine)
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When the steam turbine unit in our factory is tested, the vibration at the exhaust end is very high, almost reaching the trip value, while the vibration at the inlet end is very low, only 10~20um. During the test run of our steam turbine unit, the coupling end is fixed with a test plate to prevent the external ring gear of the coupling from shaking. Please analyze what is the cause? This post was last written by zhangya * ong edited on 2009-2-23 10:55 ]
Possible reasons: 1. Cylinder thermal expansion is blocked ； 2. The warm-up is not complete, and the cylinder or rotor is thermally deformed. ； 3. Journal or bearing failure ； 4. Steam brings water or water impact ； 5. The rotor has cracks ； 6. The axial clearance between dynamic and static parts is less than the difference in thermal expansion. ；
All possible causes upstairs have been ruled out and we have checked them all.
1. The rotational inertia of the coupling end is too large； 2. The back contact surface of the low-voltage end tile is not restrained enough or the bearing clearance is too large
There is no problem with the bearing clearance. I installed it myself.
There are two reasons for analysis: 1 The bearing tightness or clearance on the low-pressure side does not meet the standards. 2 Because it is a single test run, the coupling is not connected to the coupling of the dragging equipment, so it is not well positioned, causing vibration.
Not connecting the coupling will not affect the vibration.
A similar problem has occurred with our machine. In the end, we found that the coupling bolts were not tightened properly, causing the outer ring gear to loosen and cause vibration.
And another post is it a unit? The turbine rotor must have been balanced. Will the fixed coupling of the test plate have different thermal elevations? This post was last written by zhangya * ong edited on 2009-2-23 10:56 ]
These are two different posts, one is a small turbine, and this one is a drive turbine for the large turbine New Billund's carbon dioxide compressor. Dynamic balancing must have been done.
The steam turbine in our factory has been vibrating a lot since it was flooded once, but it can still be used: victory:
Did the rotor of the one upstairs get bent due to water intrusion?
When we drove the car to warm up the engine, all the diversion showers were turned on. They were all confirmed and there must be no problems.
It is best to check the test disk to see if the installation meets the requirements.
Could the increase in vibration be caused by the driven equipment?
Is it possible that the rear air seal gap is not adjusted properly and is worn out during operation? Is it possible that the rotor and cylinder are not concentric?
I suggest: It's best to reinstall it. Also pay attention to whether the various accessories are fully matched.
The turbine bearing should be a round bush. How about the transition to the arc interface? I hope to confirm the bearing style and size again! How is the rotor dynamic balance? Is there any deflection in the shaft?
The phenomenon that is reflected now is that the dynamic balance is not good. The bearings have just been replaced with new ones. There is no problem with drift.
1. Look at the vibration spectrum. The vibration is mainly 1 times the frequency. It can be initially judged that it is unbalanced. The vibration value increases with the number of revolutions. (There is no alignment problem with a single machine) 2. The rotor is dynamically balanced, and it won’t work if the test disk you added is not dynamically balanced at the same time. --If it doesn’t work, dismantle the coupling and give it a try. This post was last edited by wzk1998 on 2009-2-28 12:49 ]
At present, the equipment is running normally. It is basically confirmed that the high vibration of the equipment is caused by the test disk.