Bio-inspired unsteady load control to enhance power output and fatigue life of wind and tidal turbines
Lead Research Organisation:
University of Edinburgh
Department Name: Sch of Engineering
Abstract
This project aims to develop a new blade concept for wind and tidal turbines using porous blades to passively mitigate unsteady loads. It builds on nature-inspired research on the advantages of porosity and flexibility for passive flight control.
Unsteady fluid loads on wind and tidal turbines cause fatigue and power fluctuations, increasing the levelised cost of energy (LCOE). Previous work on passive morphing blades shows that they can completely mitigate load fluctuations. However, for resilience and reliable blade, flexibility may be restricted to the trailing edge, limiting mitigation efficacy.
To gain additional load mitigation, the trailing edge can be porous, with its porosity controlled passively and in tandem with its deformation. Staggered holes in the top and bottom surfaces of the trailing edge may be brought into alignment as the trailing edge is deflected by increased fluid load. This low inertia, passively controlled trailing edge could react to high frequency fluctuations thereby combining the efficacy of active, low interia control surfaces with the reduced maintenance of passive control. Additionally, unlike existing passive control methods that rely on structural couplings, the trailing edge could be tailored along the full blade span, mitigating unsteady loads down to the root to reduce flow separation and energy losses and create a cleaner wake for downstream turbines - critical for large, compacted farms.
This project capitalises on the recently concluded Leverhulme Trust (RPG-2015-255) project on the flight of the dandelion fruit, which demonstrated how the vortical flow structures and the forces on a porous surface can be controlled by porosity, making it possible to stabilise the wake behind a flow immersed body to generate new flow structures that would otherwise be too unstable to exist. This is, in fact, the mechanisms exploited by the dandelion fruit to fly, unpowered for hundreds of kilometres. We hypothesise that a similar principle is also exploited by birds, whose wings are both flexible and porous, to mitigate the effect of gusts. World-leading research groups, such as Spedding at UCLA, are currently investigating the aerodynamics of porous wings for aeronautical applications. This project will combine recent findings on the effects of porosity and flexible blades to develop a new blade concept for wind and tidal turbines.
Unsteady fluid loads on wind and tidal turbines cause fatigue and power fluctuations, increasing the levelised cost of energy (LCOE). Previous work on passive morphing blades shows that they can completely mitigate load fluctuations. However, for resilience and reliable blade, flexibility may be restricted to the trailing edge, limiting mitigation efficacy.
To gain additional load mitigation, the trailing edge can be porous, with its porosity controlled passively and in tandem with its deformation. Staggered holes in the top and bottom surfaces of the trailing edge may be brought into alignment as the trailing edge is deflected by increased fluid load. This low inertia, passively controlled trailing edge could react to high frequency fluctuations thereby combining the efficacy of active, low interia control surfaces with the reduced maintenance of passive control. Additionally, unlike existing passive control methods that rely on structural couplings, the trailing edge could be tailored along the full blade span, mitigating unsteady loads down to the root to reduce flow separation and energy losses and create a cleaner wake for downstream turbines - critical for large, compacted farms.
This project capitalises on the recently concluded Leverhulme Trust (RPG-2015-255) project on the flight of the dandelion fruit, which demonstrated how the vortical flow structures and the forces on a porous surface can be controlled by porosity, making it possible to stabilise the wake behind a flow immersed body to generate new flow structures that would otherwise be too unstable to exist. This is, in fact, the mechanisms exploited by the dandelion fruit to fly, unpowered for hundreds of kilometres. We hypothesise that a similar principle is also exploited by birds, whose wings are both flexible and porous, to mitigate the effect of gusts. World-leading research groups, such as Spedding at UCLA, are currently investigating the aerodynamics of porous wings for aeronautical applications. This project will combine recent findings on the effects of porosity and flexible blades to develop a new blade concept for wind and tidal turbines.
Planned Impact
The research challenge and skills shortage to be addressed by the proposed CDT in Wind and Marine Energy Systems is central to the success of UK plans for a high penetration of renewable energy (much of this to be from onshore and offshore wind together with other marine renewable energy sources) and thus to meeting the Government's binding EU obligations to provide 15% of UK energy from non-carbon sources by 2020.
Since this is a Centre for Doctoral Training, the primary impact on UK society in general and UK industry in particular will be through the provision of highly trained engineers, expert in wind and marine energy. Most of the CDT graduates will be expected to take up posts in the growing commercial wind and marine energy sectors, and quickly rise to positions of leadership and influence. Given the continuing importance of research, especially for offshore wind and marine energy technology , it is hoped that some graduates will remain in the Higher Education sector and develop academic careers. This would provide a further, albeit slower impact through an improved research base and capability to deal with the inevitable research challenges of the sector as it develops further commercially.
UK industry, directly and indirectly involved in the wind and marine energy, will be beneficiaries. The proposed DTC will link strongly to all sectors, OEMs, components suppliers, developers, operators and consultants, aligning its research programme in Technology Readiness Levels one to four with their concerns and priorities. The existing extensive network of Industry Partners, that closely engage with the existing DTC in Wind Energy Systems and IDC in Offshore Renewable Energy (IDCORE, will be maintained and built on to ensure this alignment is achieved. Their role will include membership of the Industrial Advisory Board, suggestion and development of topics for the first year 8 week mini-projects and the main 3 year research projects, partnering and providing advice, guidance and support. In this way the research undertaken will be directly driven by industry needs and the research outcomes will help the commercial sector address key issues facing them.
A further impact will be through dissemination of the research outcomes to the wider research community both nationally and internationally. DTC students and supervisors will continue to publish in leading international journals, and dissemination will be supplemented by attending appropriate conferences and through organisations like the European Academy of Wind Energy, the IEC and CIGRE, and most importantly through direct contact with the industrial research leaders. The proposal team has excellent contacts in both the UK power and renewable energy sectors (National Grid, Scottish and Southern Energy (SSE), and Scottish Power/Iberdrola among others) and overseas (EDF, Gamesa, Siemens, EDP, China State Grid, etc.), as well of course with the international research community (NREL, DTU/RISO, ECN, EPRI, CEPRI, Tsinghua University, Zhejiang University, UCD, etc.)
The strong links and support from the wind and marine sectors allied to the UK electricity generation sector will ensure National Impact. In addition, Strathclyde's recently established Technology Innovation Centre (TIC) partnerships with SSE and Scottish Power/Iberdrola will provide an excellent framework to promote diffusion of the ideas generated by the DTC activity into the electricity supply and renewable energy and offshore sectors. In addition good links have been established with the new TSB Offshore Renewable Energy Catapult based in Glasgow and NAREC, with both Universities represented on their Research Advisory Board.
Since this is a Centre for Doctoral Training, the primary impact on UK society in general and UK industry in particular will be through the provision of highly trained engineers, expert in wind and marine energy. Most of the CDT graduates will be expected to take up posts in the growing commercial wind and marine energy sectors, and quickly rise to positions of leadership and influence. Given the continuing importance of research, especially for offshore wind and marine energy technology , it is hoped that some graduates will remain in the Higher Education sector and develop academic careers. This would provide a further, albeit slower impact through an improved research base and capability to deal with the inevitable research challenges of the sector as it develops further commercially.
UK industry, directly and indirectly involved in the wind and marine energy, will be beneficiaries. The proposed DTC will link strongly to all sectors, OEMs, components suppliers, developers, operators and consultants, aligning its research programme in Technology Readiness Levels one to four with their concerns and priorities. The existing extensive network of Industry Partners, that closely engage with the existing DTC in Wind Energy Systems and IDC in Offshore Renewable Energy (IDCORE, will be maintained and built on to ensure this alignment is achieved. Their role will include membership of the Industrial Advisory Board, suggestion and development of topics for the first year 8 week mini-projects and the main 3 year research projects, partnering and providing advice, guidance and support. In this way the research undertaken will be directly driven by industry needs and the research outcomes will help the commercial sector address key issues facing them.
A further impact will be through dissemination of the research outcomes to the wider research community both nationally and internationally. DTC students and supervisors will continue to publish in leading international journals, and dissemination will be supplemented by attending appropriate conferences and through organisations like the European Academy of Wind Energy, the IEC and CIGRE, and most importantly through direct contact with the industrial research leaders. The proposal team has excellent contacts in both the UK power and renewable energy sectors (National Grid, Scottish and Southern Energy (SSE), and Scottish Power/Iberdrola among others) and overseas (EDF, Gamesa, Siemens, EDP, China State Grid, etc.), as well of course with the international research community (NREL, DTU/RISO, ECN, EPRI, CEPRI, Tsinghua University, Zhejiang University, UCD, etc.)
The strong links and support from the wind and marine sectors allied to the UK electricity generation sector will ensure National Impact. In addition, Strathclyde's recently established Technology Innovation Centre (TIC) partnerships with SSE and Scottish Power/Iberdrola will provide an excellent framework to promote diffusion of the ideas generated by the DTC activity into the electricity supply and renewable energy and offshore sectors. In addition good links have been established with the new TSB Offshore Renewable Energy Catapult based in Glasgow and NAREC, with both Universities represented on their Research Advisory Board.
Organisations
People |
ORCID iD |
| Ignazio Maria Viola (Primary Supervisor) | |
| Geethanjali Pavar (Student) |