Hydrodynamic performance and placement characterization of axial hydro-kinetic turbine in a compound open-channel

In this study, performance of an in-stream hydro-kinetic turbine and its impacts on a simplified river channel (known as a compound open-channel) flow has been numerically examined. To this end, a steady ReynoldsAveraged Navier-Stokes solver has been employed together with the moving reference method to simulate the turbine rotation as well as the Reynolds Stress Model (RSM) as the turbulence closure. The results showed that the presence of a hydro-kinetic turbine causes dramatic changes in the natural flow structure of the compound channel, which varies depending on the location of turbine installation. Comparison of turbine installation in various locations in the cross-section of the channel showed that minimum effects on the natural flow conditions have been occurred in the installation at the main-channel being far from the bed. It has also been observed that the bed shear stress remains virtually constant for different hydro-kinetic turbine locations. Values of the power coefficient indicate that the highest value of maximum power coefficient is obtained where the hydro-kinetic turbine is installed at the interaction zone of the compound open-channel. This observation implies that cellular secondary currents of the compound channel have positive effects on the turbine power. Finally, it is noted that the thrust coefficient variation with the installation location is insignificant compared to the variation of this coefficient with respect to the inlet velocity and the ratio of the blade flow speed to the flow speed.

Automated summary

This study numerically examined the performance of an in-stream hydro-kinetic turbine and its impacts on a simplified river channel flow. The results showed that the turbine installation location significantly affects the natural flow structure of the compound channel, while having minimal effects on the bed shear stress. Installing the turbine at the interaction zone of the compound open-channel yielded the highest maximum power coefficient.