What is the cause of the deformation of the rear axle of the steam turbine after the shutdown of the

There are two possible reasons for the increased start-up vibration after a shutdown. 1) The rotor has been bent when the machine is turned on, so the vibration is large, which may be caused by the poor hydrophobicity of the unit and the water ingress of the cylinder during the shutdown process, which is concealed by the operation personnel. 2) In the process of speed increase, serious dynamic and static friction occurs (pay attention to whether the vibration changes at the warm-up speed, if there is a change, it is very likely that dynamic and static friction occurs), resulting in bending of the rotor.

The easiest way to judge whether it has been bent before the last boot is to compare the correspondence between the speed and vibration of the ramp-up process when you start it several times (it is estimated that you will not stop when you start it once without reaching the rated speed, and you must have tried several times without success) to see if there is any change, if each change is larger, it may be that there is a dynamic and static friction; If it's the same every time (about the same), it's likely that the rotor was bent before the roll.

The rotor bends 5 wires without affecting the use of the rotor, and if it cannot be turned on, the vibration can be controlled by on-site dynamic balance.

Obviously, the large shaft of your steam turbine is bent, and the reason for the bending is not caused by the large temperature difference between the upper and lower cylinders, but the friction of the dynamic and static parts. It is recommended to do a rotor dynamic balance test.

After the blade is broken, it falls outside the cylinder, which is okay and will not cause subsequent damage, but the adjacent blade must be somewhat deformed, resulting in a change in the gap between adjacent impellers, which directly leads to metal friction and shortens the idle walking time.

If it does not fall outside the cylinder, it is still hanging, it is serious, the consequence of the straight and wide hail brother is that the impeller shaves the head, and even the adjacent impeller is inevitable, the most serious is that the whole cylinder is all bald head of the dynamic and static impeller, the large shaft is broken, and the bald shaft is broken and flies out.

Under normal circumstances, when the large shaft differential expansion and dynamic and static expansion difference are abnormal, it may affect the idling time, and it is not as good as the emergency shutdown in several cases, it is likely that the large shaft is bent, once the elasticity is bent, the idle walking time will be significantly slowed down after the emergency brake, and even when listening to the sound outside the cylinder, the metal friction sound will be clearly heard, which is the idle walking time is significantly shorter.

The idling time of the steam turbine refers to the period from the disconnection of the generator to the closing of the automatic main valve speed regulating valve, so that the rotor is completely stationary, which is called the idling time.

After the blade is broken, it falls outside the cylinder, which is okay and will not cause follow-up damage, but the blade near the Chunxin must be somewhat deformed, resulting in a change in the gap between adjacent impellers, which directly leads to metal friction and shortens the idle walking time; If Sen Qiguo did not fall outside the cylinder, still hanging, it is serious, the direct consequence is that the impeller shaves the head, and even the adjacent impeller is inevitable, the most serious is that the entire cylinder is dynamic and static impeller all bald, the large shaft is broken, the bald shaft is broken and the first wheel of the cylinder flies out, this is not to say that the time is lazy. . .

In general, when the large shaft differential expansion and dynamic and static expansion are abnormal, it may affect the idle walking time, and it is not as good as the emergency shutdown in several cases, it is likely that the large shaft is bent, once the elastic bending, the idle walking time will be significantly slowed down after the emergency brake, and even when listening to the sound outside the cylinder, the metal friction sound will be clearly heard. This is the lazy walking time is significantly shorter.

Is it too much to break, the result of friction in the moving and static parts?