Regarding the vibration level issue of the turbine, I hope fellow sailors can help.
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The Hangzhou Steam Turbine has a steam pressure of 9 MPa and a temperature of 500 degrees; the steam flow rate is 150 t/h. No major overhauls have been carried out before the problems arose. Instrumentation issues have been confirmed to be none. The current problem is that when the steam pressure drops significantly, the vibration level at the turbine’s steam inlet increases (it’s around 30 under normal conditions, but it can rise to 80 or 100, causing the turbine to shut down). The greater the drop in steam pressure, the more the vibration level increases, with no change in vacuum levels. The reasons I analyzed are: 1. bearing pad issues, 2. inflexible operation of the intake valve, 3. problems with steam quality. The current countermeasure is to increase the steam pressure to above 9.0 MPa; this indeed prevents an increase in vibration levels, but if the pressure is reduced, the vibration levels will definitely rise. I would appreciate it if fellow sailors could suggest some possible options; I’d like to learn more so that I have a direction to follow during the major repair. Thank you all.
Did it happen after restarting? If that’s the case, it’s possible that uneven heating and cooling during startup and shutdown cause elastic thermal bending of the rotor, thereby leading to high vibration levels. This issue can be resolved by restarting the system or increasing the heating time~~
In my humble opinion, as the steam pressure decreases, the axial thrust exerted on the inlet side of the turbine changes significantly. It is recommended to find a long-term solution by replacing the bearings with more reliable ones, and to pay attention to controlling the steam pressure in order to keep the axial force at the steam inlet as stable as possible.