Hydrokinetic energy technologies are emerging as a viable solution for renewable power generation. Unlike conventional hydropower turbines, hydrokinetic turbines are environmentally friendly; they operate at zero-head, and do not need dams to preserve the water. Unfortunately, they have a low efficiency which makes their design a challenging task. This work was focused on the hydrodynamic performance of horizontal axis hydrokinetic turbines (HAHkTs) under different turbine arrangements and flow conditions.
It was undertaken in an effort to improve the efficiency of small HAHkTs that harness a river\u27s kinetic energy. Four sets of experiments were performed in a water tunnel to investigate small-scale constant cross-section HAHkT models with various configurations. The first set of experiments provided insight into the operating characteristics of a 3-blade single turbine by varying its pitch angle (ΞΈ), tip speed ratio (TSR), flow speed (Uβ), and applied load. A multi-turbine system of both two and three 3- blade rotors (mounted coaxially to the same shaft) was tested in the second set of experiments. The purpose was to decrease the turbine system solidity while increasing the blade number. Here, the number of and the distance between rotors as well as the rotors relative installation angle were investigated. A long duct reducer was used to shroud single turbine and multi- turbine system in the third set of experiments. The particle image velocimetry (PIV) technique was used in the final set of experiments to examine the flow patterns at different axial locations downstream from two different turbine configurations. The effect of the flow speed on the wake characteristics was also examined in this experiment --Abstract, page iii
