What are the causes of increased axial displacement in steam turbines?

[MariaLee]

The main causes of increased axial displacement in steam turbines include: (1) Decrease in steam temperature and pressure, overload in the flow passage, and shutdown of regenerative heaters; (2) Increased steam leakage due to wear in the diaphragm shaft seal clearance; (3) Poor steam quality leading to scaling in the flow passage; (4) Water hammer occurrence; (5) Load variations. Generally, the axial thrust of condensing steam turbines increases with load; for extraction or back-pressure turbines, the maximum axial thrust may occur at a certain intermediate load. (6) Damage to thrust bearings; (7) Drop in condenser vacuum; (8) Decrease in grid frequency. Key points for handling increased axial displacement: (1) When increased axial displacement is detected, pay special attention to the temperature of thrust bearing pads and their return oil temperature, monitor turbine vibration, and listen for any abnormal sounds inside the turbine. (2) If axial displacement increases to the alarm value (+1, -1.45 mm), quickly reduce the load to bring it below the alarm value, report to the shift leader to identify the cause and take action, and keep a record. (3) If axial displacement increases to the trip value (+1.2, -1.65 mm) and the protection does not activate, and the thrust bearing pad temperature rises to 95°C, perform an emergency shutdown. (4) If axial displacement increases significantly, vibration rises notably, and bearing return oil temperature increases sharply to 75°C, perform an emergency shutdown. (5) Even if axial displacement has not reached the limit value, but thrust bearing temperature rises significantly and any thrust pad temperature reaches 95°C, and load reduction does not resolve the issue, perform a fault shutdown.

[HarleyMarie]

There are several common reasons for the increase in axial displacement of a turbocharger. First, bearing wear is a major issue. After prolonged use, the bearings of the turbo shaft may develop increased clearance due to friction, leading to excessive displacement. Second, inadequate lubrication system performance is another factor. If the engine oil is aged or insufficient, the lubrication effect deteriorates, increasing friction and causing greater axial displacement. Third, installation or alignment errors are also critical. Improper calibration during assembly or loose bolts can lead to accumulated vibrations during operation, resulting in problems. Fourth, working under high temperatures and overload conditions may cause uneven thermal expansion of turbo components, leading to deformation. Fifth, foreign contaminants such as metal debris entering the bearing area can cause jamming or abnormal wear. My suggestion is not to push through when displacement increases is detected; instead, stop and inspect to avoid further damage. Regular maintenance is essential, such as changing the engine oil periodically to maintain lubrication and checking fasteners, which can effectively delay wear and extend the turbo's lifespan. If symptoms like unusual noises or power loss occur, seek professional repair early.

[McSamuel]

Increased axial displacement in turbochargers often stems from neglecting routine maintenance. I've noticed many car owners forget to change the engine oil regularly. When the oil deteriorates, its lubrication capability decreases, leading to increased bearing friction and greater displacement. Additionally, driving habits play a role—frequent high-RPM operation puts extra load on the turbo, accelerating component fatigue. External factors like bumpy roads or dust intrusion can also worsen bearing wear. Of course, normal aging is unavoidable; bearings naturally loosen and exceed displacement limits over time. The key is early detection—pay attention to unusual noises or power loss and get it checked promptly. Don't underestimate this issue—excessive displacement may cause turbo failure or even engine damage. On the flip side, prevention is straightforward: during each service, have the mechanic check clearances and use quality oil. In short, good habits save big money.

[LaCarson]

The causes of increased axial displacement in turbochargers include: bearing wear leading to increased clearance, insufficient lubrication causing increased friction, improper component installation such as misalignment, thermal deformation, or contamination by external impurities. It is recommended to inspect the oil system to ensure proper lubrication, check for loose fastening screws, and promptly clean and replace components. Do not wait for major issues to arise.