High performance ocean energy harvesting turbine design–A new casing treatment scheme. (15th June 2015)

• Record Type: Journal Article
• Authors: Halder, Paresh; Samad, Abdus; Kim, Jin-Hyuk; Choi, Young-Seok
• Is Part Of: Energy. Volume 86(2015)
• Page Start: 219
• Page End: 231
• Publication Date: 2015-06-15
• Subjects: Tip gap -- Wells turbine -- Wave energy -- Stall delay -- Casing groove; Power resources -- Periodicals; Power (Mechanics) -- Periodicals; Energy consumption -- Periodicals; 333.7905
• DOI: 10.1016/j.energy.2015.03.131
• Languages: English
• ISSNs: 0360-5442

Abstract

Abstract: Delaying a stall improves the performance of any turbomachinery system. TC (tip clearance), which is used in a bi-directional flow Wells turbine of an ocean wave energy device, changes the flow pattern on the turbine blade suction surface, while changing or modifying the TC zone can help obtaining a delayed stall. In the present work, a new tip grooving scheme is introduced and the performance is compared for different tip groove depths and TCs of a Wells turbine. The performance is defined in terms of wider operating range or stall delay, power production and efficiency. The problem was solved by a numerical analysis technique. A multi-block meshing scheme was employed to generate structured and hexahedral elements in the computational domain and the flow was solved in ANSYS CFX ® v14.5 by solving Reynolds-averaged Navier Stokes equations. It was found that the grooves improve the turbine operating range and power production as compared to those of the turbine without a groove. The groove depth of 3% of the chord length produced highest power and widest operating range. Using the circumferential groove, 26% increase in turbine power output for a particular operating point is achieved. Highlights: A high performance wave energy turbine design philosophy is demonstrated. A new casing grooving scheme for Wells turbine for wave energy conversion is proposed. An optimal groove depth performs better in terms of operating range is reported. A comparative study of different tip clearance and grove depth is presented.