Development of a test rig to evaluate abrasive wear on Pelton turbine nozzles. A case study of Chivor Hydropower

Over 75% of domestic electric power consumption in Colombia is supplied by hydropower. Abrasive wear is degrading turbine components such as Pelton needle valve nozzles. This problem has been studied on the components themselves (in situ). However, it was necessary reproduce the same hydro-abrasive phenomena in a controlled laboratory environment. This study describes the design and construction of a test rig capable of replicating the same wear mechanism present in Pelton needle valve nozzles at Chivor hydroelectric plant. The development of the test rig allowed to conduct empirical testing for the comparison of the plasma nitriding process versus the WC-Co-Cr coat deposited by HVOF to extend the lifetime of the nozzle. Both processes showed significant improvement in hardness and wear resistance compared to the original material specification of the needle valves.