Session: 02-08-01 Risk and Reliability of Renewable Energy Devices 1

Paper Number: 125707

125707 - Non-Contact Dynamic Testing of a Next-Generation Helical Crossflow Tidal Turbine Foil Using a Laser Scanning Vibrometer 

The renewable energy sector is strategically focusing on de-risking the tidal energy converters, aiming to facilitate the deployment of the next-generation, highly efficient tidal energy devices. This effort is to reduce the cost of tidal energy and thus enable the development of tidal energy as a key contributor to renewable energy generation. This process encompasses thorough evaluations of design, materials, and operational aspects, coupled with rigorous testing procedures to guarantee the reliability and efficacy of these state-of-the-art converters. In this context, this study presents a comprehensive dynamic testing approach aimed at evaluating the structural performance of a next-generation helical crossflow tidal turbine foil manufactured using carbon fibre prepregs. It was encouraged to use a Laser Scanning Vibrometer (LSV) for assessing the dynamic characteristics of the foil because of its capacity to expedite testing procedures and data processing. Furthermore, the data processing system yields superior accuracy and precision in results compared to conventional methodologies employing accelerometers. A prototype, full-scale, 5-metre foil, underwent dynamic testing, was securely affixed to three composite struts linked to a robust steel frame which was connected to a reinforced concrete floor in the Large Structures Testing Laboratory at the University of Galway. The testing setup aligned to the guidelines provided in DNVGL-ST-0164 and IEC DTS 62600-3 standards, focusing particularly on dynamic, static, fatigue, and residual strength testing. Fatigue testing is being completed using an unbalanced rotating mass (URM) attached to the higher tip end of the foil. The URM, weighing 60.87kg, which exerts a significant influence on the dynamic response of the foil. Consequently, two distinct sets of dynamic testing were conducted, one with and one without the URM system, prior to static testing.

For dynamic testing, an LSV equipped with a single scanning head, was employed in combination with an accelerometer to examine and validate the foil's dynamic response. Additionally, strain gauges adhered to the tidal turbine foil were utilised to estimate its natural frequencies, employing the Fast Fourier Transform method. The dynamic responses obtained from LSV, accelerometer, and strain gauge data exhibited a strong correlation, further validating the reliability of the LSV system. Notably, the LSV system demonstrated ability in capturing the mode shape of the foil. This facilitates the detection of any potential damage incurred during testing. Furthermore, the research showcases how altering the mass of tidal turbine systems affects their dynamic response. This offers valuable knowledge to designers regarding the criticality of managing structure mass to minimize the probability of failures in large-scale operational tidal energy systems.

Due to physical space limitations, the foil was scanned separately in the four identified regions, as capturing the entire 5-metre length in a single pass proved impossible with a single scanning head. Consequently, this study lays the foundation for future endeavours seeking to establish a standardized testing protocol for LSVs in evaluating the dynamic response of larger tidal turbines. Furthermore, the research provides valuable insights towards the optimisation of the design and performance of next-generation tidal turbine technologies, thereby paving the way for more efficient and sustainable marine energy solutions in the future.

Presenting Author: Tenis Ranjan Munaweera Thanthirige University of Galway

Presenting Author Biography: Munaweera Thanthirige Tenis Ranjan is a PhD student in Civil Engineering at the University of Galway. He holds a Bachelor of Science (BSc) degree and a Master of Philosophy (MPhil) degree in Mechanical and Manufacturing Engineering. With a strong background in composite manufacturing and structural testing of tidal and wind turbine blades, Tenis has gained valuable experience in Finite Element Analysis (FEA) for structures, which allows him to analyze and simulate the behavior of various engineering components and systems. This expertise enables him to assess the structural integrity and performance of composite materials used in the manufacturing of tidal and wind turbine blades.

Prior to his doctoral studies, Tenis served as a lecturer for seven years at the Faculty of Engineering, University of Ruhuna in Sri Lanka. During his time there, he mainly taught modules on thermodynamics and fluid dynamics, providing instruction and guidance to students pursuing engineering degrees. Overall, Tenis possesses a diverse range of skills and experiences in the fields of mechanical and civil engineering, particularly in composite manufacturing, structural testing, and FEA analysis. His background as a lecturer also highlights his aptitude for teaching and knowledge dissemination.

Authors:

Tenis Ranjan Munaweera Thanthirige University of Galway
Michael Flanagan University of Galway
Ciaran Kennedy University of Galway
Yadong Jiang University of Galway
Vahid Fakhari University of Galway
Carlos Bachour University of Galway
Clement Courade ORPC Ireland
Patrick Cronin ORPC Ireland
Conor Dillon ORPC Ireland
Jarlath Mcentee ORPC Ireland
Tomas Flanagan ÉireComposites Teo
Jamie Goggins University of Galway
William Finnegan University of Galway