The hazards and repair methods of turbine impeller cavitation

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During the operation of hydraulic turbines, they are affected by the impact and shearing effects of water flow, sediment, etc. Cavitation, corrosion, and abrasion have become prominent problems that affect the efficient and safe operation of hydraulic turbines. This problem has been plaguing the operation and maintenance management of enterprises for a long time, especially in areas with poor water quality environments. The impeller is often the most severely corroded during operation of a water turbine. When the impeller is severely corroded, the efficiency of the water wheel drops significantly and the water wheel cannot operate at full load. Vibrations exceeding the specified value may also occur, causing a series of secondary failures, such as: The radial thrust bearing of the hydraulic turbine is damaged due to vibration, the connecting thread is loose, the sealing material is worn, causing water and oil leakage, and the balance parameters of the entire unit are offset, etc. Prevention and control measures for cavitation: 1. Use corrosion-resistant stainless steel electrodes to repair the cavitation parts ； 2. Spray anti-corrosion coating ； 3. New technologies such as thermal spraying technology ； The methods mentioned above are currently commonly used, but in daily operations, repair welding has various problems. The stress concentration may cause the impeller to deform, and the operation is complicated, requiring gouging, welding, smoothing and other operations. Thermal spray technology has the characteristics of quick repair, but the operation is troublesome and requires special tools and skilled operators to complete the work. Improper operation will cause bulging, sagging and other phenomena. Spraying anti-corrosion coatings is also a commonly used method. Currently, the commonly used anti-corrosion coatings, such as Sole carbon nanopolymer materials, have superior performance and are widely used.