潮流能水轮机流场特性的数值与实验研究

This article combines numerical simulations and model experiments to study the influence of flow field characteristics on the hydrodynamic performance of turbines in the near-field. The effect of different factors such as inflow velocity and tip-speed ratio on the wake field characteristics in the far-field is analyzed. The research results show that the relative error of power coefficient between the numerical simulation result (0.37) and the experimental result (0.36) is 0.3% at the designed tip speed ratio, and the relative error of drag coefficient between the numerical simulation result (0.73) and the experimental result (0.76) is −4%. There are significant three-dimensional flow phenomena at the blade tip of the tidal turbine, there is a radial velocity (0.24 m/s) at the front of the turbine disk which flows from the blade root to the tip, and there is a radial velocity (0.14 m/s) at the rear of the turbine disk which flows from the blade tip to the root. The downwash flow velocity near the wake zone of the blade tip causes a decrease in the energy conversion efficiency of the turbine. The inflow velocity has no a significant impact on the recovery of axial velocity in the wake region;In the near wake region(within 5Ddistance from the disk), with the increase of tip-speed ratio, the recovery of axial velocity in the wake shows a gradually decreasing trend. When the distance from the water turbine disk exceeds 10D, the tip-speed ratio does not have a significant effect on the recovery of axial velocity in the wake. However, the increase of tip-speed ratio will shorten the existence time of the blade vortex and make the location where the blade vortex is broken closer to the water turbine disk.