Robert Ellis ERC-TG - 4th AWTEC Conference
Through the travel funding provided by PRIMARE I was able to travel to Taiwan to attend and present at the 4th Asian Wave and Tidal Energy Conference (AWTEC). AWTEC provides a great platform to meet others involved on Marine Renewable Energy (MRE) areas and get a glimpse at some of the work that is going on both in industry and academia by students and researchers a like. As part of this conference I presented on a part of my work to this point.
The work I presented on was titled ‘Design Process for a Scale Horizontal Axis Tidal Turbine Blade’. At Cardiff University we have been using the Wortmann FX63-137 aerofoil for previous blade designs. It was initially designed to have a self-starting capability which utilised the high lift and low stall characteristics of the Wortmann aerofoil. Development of a new turbine has led to redesigning the blade whilst maintaining the Wortmann FX63-137 aerofoil. Other than increasing the blade length, three key areas of the blade were investigated for the new design. These areas were the blade twist, chord length and the root-hub attachment. In addition to these design requirements two restrictions were placed on the design; the CP was to be greater than the original design and the CT was to not be significantly increased.
The presentation described the design stages utilising both Blade Element Momentum Theory (BEMT) code developed at Strathclyde University and the Computational Fluid Dynamics (CFD) package ANSYS CFX. The fundamental blade design started with the original blade and morphed using the BEMT code. CFD was then used to model the blade and the hydrodynamics. A comparison between the results for the BEMT and the CFD models showed good agreement. At this point the CFD model did not contain a stanchion with an aim to keep it as similar to the BEMT model as possible. The final design resulted in a reduced twist distribution, a modified chord length and the use of a symmetrical aerofoil at the root to provide the necessary width for the hub attachment. The CP was found to have increased to 0.45 from 0.42 and the maximum CT was 0.9 which was not significantly greater than that of previous blade designs. The CFD model was developed to include the stanchion and the geometry being used for the runs was changed to represent the INSEAN tow tank facility were experimental testing was conducted to provide validation. The power curves that came out of the results from the INSEAN test compared well to the numerical modelling techniques.
Having now achieved a good characterisation of the turbine through experimental testing, combined with the confidence in the CFD model, further work is now being undertaken with an increased number of turbines to look at array interaction.
The European Wave and Tidal Energy Conference takes place in September 2019 in Naples. It would be great to present my future work at this event with the help of future PRIMARE travel funding, as it helps expose me to many members of the Marine Renewable Community, whilst also having a chance to share my work.