Influence of turbulence and fluid thermophysical properties on cavitation erosion predictions in channel flow geometries 2019-01-0290
Cavitation and cavitation-induced erosion have been observed in fuel injectors in regions of high acceleration and low pressure. Although these phenomena can have a large influence on the performance and lifetime of injector hardware, questions still remain on how these physics should be accurately and efficiently represented within a computational fluid dynamics model. While several studies have focused on the validation of cavitation predictions within canonical and realistic injector geometries, it is not well documented what influence the numerical and physical parameters selected to represent turbulence and phase change will have on the predictions for cavitation erosion propensity and severity.
In this work, a range of numerical and physical parameters are evaluated within the mixture modeling approach in CONVERGE to understand their influence on predictions of cavitation, condensation and erosion. Particular attention is paid to grid resolution, turbulence model and near-wall treatment, dissolved gas content, fuel surrogate properties, and surface finish and imperfections. Assessment of cavitation predictions are conducted through comparison of measured and predicted mass flow rates and cavitation probability distributions across a range of pressure drop conditions in two channel flow geometries with different inlet radii of curvatures. Predictions for hydrodynamic impact loading and cavitation erosion are compared with experimentally measured incubation periods and critical sites for erosion. Based on these findings, recommendations are provided for modeling turbulent cavitating flows to improve predictions for cavitation-induced erosion.
Gina M. Magnotti, Michele Battistoni, Kaushik Saha, Sibendu Som
Argonne National Laboratory, Universita degli Studi di Perugia, Indian Institute of Technology - Delhi