The original aerodynamic design of a non-cavitating marine turbine exhibited performance-degrading cavitation in the hub region at high rotation rate. Using a numerical optimization approach, the cavitation was fully eliminated by updating the local geometry of turbine helical blades. Computational outputs were obtained using a combination of ANSYS SpaceClaim, ANSYS CFX and Fluent, ANSYS Simplorer and ANSYS optiSLang software working in the ANSYS Workbench 'end-to-end' environment.
The classic Nautilus wind turbines comprise three circular blades with uniform thickness wrapped around a shaft. This creates a three-dimensional conical turbine, similar to shells found on the beach or to roses in a garden. Marine turbines are designed using the same principles as wind turbines, but they are used in the different conditions.
The goal of this project was to redesign a cost-effective wind turbine rotor optimized for underwater use. Optimization of the dimension, form and position of the shroud and airfoil geometry helped in reducing the negative effects of cavitation.
We decided to use Xfoil (quick, verified and widely used panel method solver) as the main solver. Xfoil performs analysis of 1,000 airfoils in an hour, making 'what if' studies very fast and efficient. As an optimizer we chose ANSYS optiSLang — a best-in-class, robust optimizer with user-friendly settings. After optimization, the data was transferred to ANSYS CFD for detailed fluid flow simulation.
We reduced simulation time and increased simulation efficiency in a fully automated design process for a marine turbine, resulting in a savings of approximately $100,000 per project in engineering labor costs. Full automation also eliminates human-related faults and increases simulation efficiency. The developed workflow is universal and can be easily adapted for various industry applications.