Linking cavitation collapse energy with the erosion incubation period
Gina M. Magnotti  1, *@  , Michele Battistoni  2@  , Kaushik Saha  3@  , Sibendu Som  1@  
1 : Argonne National Laboratory
9700 S Cass Ave, Lemont, IL, 60439 -  United States
2 : Università degli Studi di Perugia
piazza Università, 1, 06123 Perugia -  Italy
3 : Indian Institute of Technology Delhi
Hauz Khas, New Delhi - 110 016. India -  India
* : Corresponding author

Cavitation-induced erosion is the result of repeated impacts from cavitation collapse events on a solid surface. To improve representation of the incubation period before material rupture within multiphase flow simulations, a new physics-based metric was derived based on cumulative energy absorbed by the solid material from repeated hydrodynamic impacts. Previous work by the authors validated the modeling framework through comparison of critical erosion sites and relative erosion severity with available experimental data. In this study, the predictive capabilities of the cavitation erosion metric are extended by relating the predicted stored energy with the solid material properties to estimate the incubation period. To extend the rigor of validation of the erosion predictions, the turbulent multiphase flow development was simulated over a range of Reynolds (Re = 1.5-2.0·105) and cavitation number (K = 1.60-1.78) conditions in an aluminum channel geometry featuring a sharp inlet corner to promote cavitation. The multiphase flow within the channel was modeled using a compressible mixture model, where phase change was represented with the Homogeneous Relaxation Model (HRM) and the turbulent flow evolution was modeled using a dynamic structure approach for Large Eddy Simulations (LES). When the average peak pressure was related to the incubation period, the incubation period and its sensitivity to changes in flow conditions was found to be overpredicted. In contrast, using the stored energy metric, multiphase flow simulations demonstrated accurate representation of the sensitivity of erosion severity to changes in flow conditions, and quantitative agreement of the predicted incubation period within 2% of the experimentally measured incubation period.

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