592 / 2019-01-19 18:55:54

Development and Application on Monitoring Thickness of Thrust Bearing Oil Film for Large-Capacity Hydropower Unit

thrust bearing, thickness of oil film, on-line monitoring

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Thrust bearing is a core component of hydropower unit, which bears the weight of rotor and axial hydraulic thrust. The performance and health status of thrust bearing directly affects the operation safety and may influence output and efficiency of the unit. With development of hydropower technology, thrust loads are increasing continuously. Of all commercial operating hydropower units, thrust load has exceeded 50000kN and intensity of pressure has exceeded 5MPa. It is essential and urgent of monitoring for thrust bearing operation.
Thrust bearing is dynamic-pressure bearing working with the oil film built by hydrodynamic lubrication mechanism. The performance of oil film directly affects the operation status of thrust bearing. The operation status of thrust bearing can be evaluated based on operation parameters, such as thickness, pressure of oil film, oil temperature, thrust pad temperature, oil level, etc. Compared with other parameters, thickness of oil film changes rapidly and can reflects the posture of thrust pad. In recent years, research on thickness of oil film mainly focus on off-line measurement and test analysis, rarely on on-line monitoring.
A monitoring device is developed based on actual structure of thrust bearing on Xiangjiaba hydropower station in this paper. The device has been applied at site and realized on-line monitoring on thickness of thrust bearing oil film. Monitoring data reflects characteristics of oil film on different operation conditions, especially on different loads. The monitoring device has achieved expectant effects. It is a successful application and a helpful reference of on-line monitoring for thrust bearing oil film on large-capacity hydropower unit.