A Novel Swirl Generator for Improving the Performance of Marine Current Turbine

Marine energy is one of the areas of high potential to improve Egypt’s renewable energy mix under the national 2030 development plan. The New Delta national project aims to develop the north-western Mediterranean coast of Egypt. In this coastal part of the Mediterranean, marine current speeds are low, however, they have consistent and homogenous directions along the year. Horizontal Axis marine current turbines (HAMCT) are good candidate to harness marine energy in this location. However, at such low current speeds, these turbines have low hydrodynamic performance.

This thesis conceptualizes and validates a novel static device that is designed to improve the hydrodynamic performance of HAMCT under transitional flow conditions. This device is called the Vane Swirl Generator (VSG). It is a static structure of twisted flat vanes to be installed upstream HAMCT. The function of VSG is to convert part of the axial momentum of the incoming flow into rotating momentum to improve lift force and reduce drag resistance.
The literature review of this thesis revealed a severe scarcity of available information on HAMCTs’ hydrodynamic performance under transitional flow conditions. This is because most of the existing platforms and R&D projects are focusing on regions with high current speeds.

In order to demonstrate and validate the proposed VSG concept, a methodology based on Computational Fluid Dynamics (CFD) has been carried out. The CFD methodology was undertaken in two validation stages and one parametric analysis stage. The total number of simulations reported in this thesis is 110 simulations. The only available comprehensive study on HAMCTs under transitional flow conditions was conducted in Fiji Island and was adopted as the benchmark case-study to validate the CFD models in this thesis.

The CFD modeling approach was parametrized based on the angle of attack (AoA) starting from theoretical 2D simulations, then 3D single-blade simulations, then 3D full-scale turbine simulation. A turbulence modeling comparison revealed that the SST