Aqua (Feb 2022)
Parametric analysis of discrete multiple-cavity models with the quasi-two-dimensional friction model for transient cavitating pipe flows
Abstract
Discrete multiple-cavity models coupled with quasi-two-dimensional (quasi-2D) friction models are effective solutions to simulating transient cavitation pipe flows. The simulation accuracy of such models hinges upon the understanding of key parameters of the models, which remains elusive so far. To address such an open issue, this paper employs the discrete vapor cavity model (DVCM) and the discrete gas cavity model (DGCM), combined with the quasi-2D friction model, with a particular focus on revealing the sensitivity of these models to the key parameters such as grid number and weighting parameters. Based on the quantitative analysis and pressure fluctuation history, a method is developed to evaluate the accuracy of numerical results. Results show that the inclusion of the quasi-2D friction model improves the accuracy of predicting time of cavity formation and collapse; however, it does not affect the selection of grid number. Meanwhile, numerical results are sensitive to the weighting parameter of the viscous term in the quasi-2D friction model except for the case of low-intensity cavitation and its value of 1 is suggested for all cases. From the practical point of view, our finding is helpful to understand the feature of discrete multiple-cavity models and improve the simulating accuracy of transient cavitation pipe flows. HIGHLIGHTS For the two-dimensional discrete vapor cavity model (2D-DVCM) and the two-dimensional discrete gas cavity model (2D-DGCM), the selection of grid number is independent of the inclusion of the friction model and only depends on the assumption of the cavitation model.; The 2D-DVCM and 2D-DGCM can accurately predict the time of cavity formation and collapse.; A procedure for evaluating the accuracy of numerical results is proposed considering the complexity of pressure fluctuation.;
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