Flow field around hydrokinetic turbines

In the search for clean, renewable and sustainable energy, the hydrokinetic energy which is harnessed from moving water of rivers, streams and oceans is being studied as a predictable and environmentally benign source. Compare to conventional hydropower turbines, hydrokinetic turbines are new technology in electricity generation and need to be improved from efficiency point of view. In this study, a vertical axis cross-flow hydrokinetic turbine, namely, a modified form of Savonius turbine was investigated. The working principles of cross-flow hydrokinetic turbines are different from those of commonly used horizontal axis turbines. The advantages of this type of turbines are; independency from the current direction including reversibility, stacking and self-starting without complex pitching mechanisms. The turbine has been simulated in a three dimensional and fully developed rectangular open channel flow. Computational fluid dynamics (CFD) simulation of the hydrokinetic turbine was performed by computationally solving the Reynolds-Averaged Navier-Stokes Equations (RANS). In computational studies ANSYS FLUENT, which is commercially available software was employed. CFD can be used to support turbine design and performance over a wide range of parameters to minimize the number of prototypes which are used for optimization and experimental studies. CFD can also provide a cost-effective way of evaluating detailed full scale effects, such as mooring lines or local bottom bathymetry features, on both turbine performance and environmental assessment. Keywords: Computational Fluid Dynamics, Hydrokinetic Turbines, Kinetic Energy, Renewable Energy, ANSYS FLUENT