A Marine Hydrokinetic Turbine Design Targeting Enhanced Operational Performance

Abstract:

Marine Hydrokinetic Turbine technologies continue to advance towards commercialization to exploit the promising source of sustainable power generation in water resources. The Applied Research Laboratory / Penn State University, Sandia National Laboratories and the University of California at Davis designed a high-performance hydrokinetic turbine rotor, MHKF1, developed to balance 1) hydrodynamic performance (high power production C_P over wide operating range), 2) limited fouling sensitivity 3) structural efficiency, 4) good stall and cavitation performance, 5) low singing susceptibility 6) hydrodynamic and geometric compatibility to scaling and 7) potential OpEx cost reduction. The MHKF1 turbine was fabricated and tested at a 1:8.7 scale to confirm design performance and provide an open platform dataset for community use. The high Reynolds number (Re) water tunnel test of the three-bladed, horizontal-axis rotor recorded powering coefficients (power, torque and thrust) versus tip-speed-ratio (TSR), blade loading, the inlet and near-wake flow field, cavitation performance, and radiated noise generation. Measurements also included steady and unsteady driveshaft loading, blade strain, and tower pressures. Tests were conducted over a range of Re’s to capture the effect of Re scaling on turbine performance. State-of-the-art measurements exhibited the complex flow physics, performance characteristics and flow field effects at unprecedented fidelity, accuracy and resolution for this MHKF1 rotor. Detailed flow mapping using laser Doppler velocimetry, and planar and stereo particle image velocimetry includes measurements of mean velocity and turbulent Reynolds stresses. Results confirmed the design performance goals of the MHKF1 rotor that could be evaluated in the test. The MHKF1 rotor exhibited a measured, relatively large peak Cp ~0.47 and maintains a C_P value above 0.4 over a large range of TSRs, between 2.9 to 6.9. Radiated sound power using nearby hydrophone with an in situ calibration was performed. The full database, available at the United States Department of Energy’s marine and hydrokinetic data repository, includes tunnel and model Computer Aided Design geometry files and inflow data sufficient for a “Model-the-Test” computational Verification and Validation study.