Effect of tribometer configuration on the analysis of hydromachinery wear failure

• Hard particle and cavitation erosion synergy was evaluated using CFD.
• Cavitation inducers configurations have strong influence in specimens wear.
• Narrow inducers promote sand erosion, while wide inducers promote cavitation.
• Simulated tribometer can reproduce well the wear conditions of a Francis runner.

Slurry erosion and cavitation erosion tribometers are used to evaluate wear on materials of hydromachinery components, in this work numerical simulations based on computational fluid dynamics (CFD) were implemented with the aim to analyze the influence of parameters such as shape and size of cavitation inducers, rotational speed, particle concentration and cavitation inducer-specimen separation over the mass loss rate. Operating parameters were determined, which are suitable to reproduce typical cavitation erosion and slurry erosion conditions presented in turbomachinery devices like Francis turbine runners under off-design conditions or exposed to a high amount of sediments. CFD analysis provides a numerical insight about the flow field and its behavior due to the influence of shape and location of the cavitation inducers aiming to predict the zone where the cavitation process takes place. Also, it was found that CFD simulation coupled with particle tracking methods provide an understanding about the interaction between the hard particles and the surfaces tested, and its influence over erosion rates.