Compressor vibration
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In a turbine unit equipped with both a low-pressure cylinder and a high-pressure cylinder, after replacing the high-pressure cylinder rotor, the vibration was normal at 8,000 revolutions per minute, but rose to over 30 units at 11,000 revolutions per minute.
First, check whether the bearing clearance is appropriate. Has the second-newest rotor been subjected to high-speed dynamic balancing? Is 11,000 the critical speed of the rotor? If even one of these conditions is not met, vibrations may occur
Which is the rated speed? Is it a rigid shaft, or a flexible shaft?
(1) Poor alignment. (2) Excessive bearing clearance or damage. (3) The bearing shell cover bolts or foundation bolts are loose. (4) The rotor is not well dynamically balanced. (5) The seal contacts the rotor. (6) Shaft bending. (7) Wear of the tooth surfaces of the gear coupling or accumulation of oil dirt.
Turbine maintenance should be carried out with care. I think it’s better to analyze it mainly from these two aspects: 1: Whether there are any changes in the process operation, such as steam quality, process gas flow rate, etc ； 2: Are there any oversight in the control points during the maintenance process? For example, has the newly replaced rotor been inspected (for dynamic balance, cleanliness, damage, etc.?), was quality control ensured during installation (was the cold alignment curve satisfactory?), and have all other components been checked and verified?
It’s comprehensive enough; it seems that the issue of critical speed also comes into play, as well as problems related to thermal misalignment or thermal dynamic balance. Only by examining the spectrum diagram can meaningful insights be obtained.
It seems there’s a problem with the bearing www.sdosly.com :L:L
Give high-speed dynamic balancing a try! With such a brief description of the vibration problem, everyone can only make random guesses; to solve it, one has to examine things one by one or look at the spectrum graphs