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Questioning the ASTM G32-16 (stationary specimen) standard cavitation erosion test
Matevž Dular1, Guillermo Enrique Barragan Montalvo2, Marko Hočevar3
1Faculty of Mechanical Engineering, University of Ljubljana, Askerceva 6, 1000 Ljubljana, SI, Slovenia; Institute for Physics, Otto von Guerricke University, Universitätsplatz 2, 39106 Magdeburg, DE, Germany.
Ultrasonics Sonochemistry
|June 3, 2024
Summary
The study questions the validity of the ASTM G-32 cavitation erosion test. Varying the gap in indirect testing revealed significant differences in erosion rates and cavitation dynamics compared to real-world scenarios.
Area of Science:
- Materials Science
- Fluid Dynamics
- Tribology
Background:
- Cavitation erosion is a major issue in hydraulic turbomachinery.
- Standardized tests like ASTM G-32 are used to evaluate material resistance.
- Existing test methods may not accurately represent real-world cavitation conditions.
Purpose of the Study:
- To investigate the influence of specimen-horn gap on cavitation erosion.
- To compare erosion rates and cavitation dynamics across different gap sizes.
- To assess the comparability of standardized tests with actual hydrodynamic cavitation.
Main Methods:
- Performed stationary specimen cavitation erosion tests with variable gaps (0.3–4 mm).
- Utilized high-speed visualization to observe cavitation dynamics.
- Developed a simple model to predict shock wave occurrence.
Main Results:
- Cavitation erosion rate is highly dependent on the gap distance.
- Cavitation dynamics change significantly in small gaps, forming large, slow-collapsing bubbles.
- Observed differences in bubble morphology and collapse behavior compared to larger gaps.
Conclusions:
- The ASTM G-32 test's indirect method may not accurately simulate turbomachinery cavitation.
- Gap size critically influences cavitation erosion and dynamics.
- Further research is needed to validate current testing standards against real-world applications.
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