Characteristics of Hydrodynamic Forces and Torque on Darrieus Type Water Turbines for Current Power Generation Systems with CFD Computations

This paper describes the drag coefficient and the lift coefficient of Darrieus type turbines, and also discusses accuracy of numerical calculations of Darrieus type water turbines with computational fluid dynamics (CFD) comparing with some results of model experiments by us. Corresponding Darrieus turbines are a vertical blade type. Objectives of this study are to investigate follows: 1) characteristics of hydrodynamic forces on a fixed blade with several attack angles, 2) characteristics of hydrodynamic forces and torques of fixed three blades, 3) rotation characteristics of the turbine without restoring loads and 4) the above things are confirmed and discussed with model experiments and CFD computations. Finally a method to improve the torque performance is investigated with optimization of attaching angles of blades. From the results, it is confirmed that CFD computations are useful and it is possible to improve torque performance with the blade element and the momentum combined theory.