An Alternative Approach to Repair of Cavitation Damage for America’s Hydropower Fleet

Christopher Smith and Kenneth Ross (Pacific Northwest National Laboratory)

Cavitation erosion damage is a significant aging infrastructure issue for the United States’ hydropower industry. While cavitation erosion damage can and is currently repaired via gas metal arc welding, the resulting heat affected zone has inferior cavitation corrosion performance. This necessitates ever increasing repair frequency and thus exacerbates downtime and lost revenue after an initial repair. In addition, with the increasing integration of other renewable energy sources onto the electric grid, the hydropower fleet is being required to operate in less optimal operating conditions to counteract the variable input of other renewable energy sources. These operating conditions are in regimes where cavitation is more prone to occur. These factors create a situation where an alternative repair process that results in improved cavitation erosion performs would be highly beneficial to the hydropower industry. To this end, PNNL is developing the cold spray coating process as an alternative and has demonstrated multi factor improvement in cavitation erosion resistance in accelerated cavitation testing. This presentation will review this repair application and the optimization of the cold spray process for cavitation erosion resistance for the hydropower industry.