A numerical analysis to study the effect of radius ratio and attachment angle on hybrid hydrokinetic turbine performance

The performance of a hybrid hydrokinetic turbine rotor under different operating conditions is investigated in this study. The effects of radius ratio and attachment angle on the power coefficient, self-starting capability and flow behavior around the turbine were simulated using commercially available software, ANSYS, with FLUENT as the solver. Realizable kappa-epsilon turbulence model has been used to solve the unsteady Reynolds-Averaged Navier-Stokes (URANS) equations. We compared the performance of a hybrid hydrokinetic turbine with the identically designed hybrid wind turbine under similar input power conditions. The hydrokinetic turbine rotor showed better performance than that of wind turbine rotor. The maximum values of coefficient of power (C-p) and torque (C-T) occur at attachment angles of 30 degrees and 60 degrees for a radius ratio of 0.2. At an attachment angle of 90 degrees, fluctuations in C-T were minimized. (C) 2018 International Energy Initiative. Published by Elsevier Inc. All rights reserved.