SBIR Phase I: Numerical Simulation of Cavitating Flows Using an Innovative Probability Density Function Model for Phase Change

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This SBIR project will develop, validate and demonstrate a cavitation model suitable for multidimensional steady and transient simulations of cavitating flows. The lack of prediction capability for cavitating flows is a critical road block in the development of many engineering equipment and biomedical devices. The proposed model will employ a transport equation for vapor with full account of vapor generation/destruction and turbulent fluctuations in velocity and pressure. The phase change rates will depend upon thermodynamic properties of fluid, and the flow characteristics, particularly turbulent pressure fluctuations. The pressure fluctuations will be related to the turbulent kinetic energy of flow. A Probability Density Function (PDF) approach will be used to calculate the local time-mean phase change rates from instantaneous pressure values. In Phase I study, the model will be incorporated in a finite-volume, pressure-based, CFD code and applied to three benchmark problems e.g., orifice, venturi and hydrofoil. Phase II work will include several modifications (e.g., bubble dynamics and velocity slip), extensive validation and practical applications. The developed cavitation model will enable improved designs of engineering equipment using pumps, propellers, orifices, hydrofoils, and hydrostatic bearings and biomedical devices such as mechanical heart valves. The cavitation model will be useable with various (and codes. CFDRC will commercialize it in conjunction with its commercial CFD code, CFD-ACE.