A Wells turbine for wave power conversion has hysteretic characteristics in a reciprocating flow. The hysteretic loop is opposite to the well-known dynamic stall of an airfoil. In this paper, the mechanism of the hyst...A Wells turbine for wave power conversion has hysteretic characteristics in a reciprocating flow. The hysteretic loop is opposite to the well-known dynamic stall of an airfoil. In this paper, the mechanism of the hysteretic behavior was elucidated by an unsteady 3-dimensional Navier-Stokes numerical simulation. It was found that the hysteretic behavior was associated with a streamwise vortical flow appearing near the blade suction surface. The effects of hub-to-tip ratio and tip clearance on the hysteretic characteristics of the Wells turbine have also been discussed in this paper.展开更多
In order to improve the performance of the Wells turbine for wave energy conversion, the effect of end plates on the turbine characteristics has been investigated experimentally by model testing under steady flow cond...In order to improve the performance of the Wells turbine for wave energy conversion, the effect of end plates on the turbine characteristics has been investigated experimentally by model testing under steady flow conditions. The end plate attached to the tip of the original rotor blade is slightly larger than the original blade profile. The characteristics of the Wells turbine with end plates have been compared with those of the original Wells turbine, i.e., the turbine without end plate. As a result, it has been concluded that the characteristics of the Wells turbine with end plates are superior to those of the original Wells turbine and the characteristics are dependent on the size and position of end plate. Furthermore, the effect of annular plate on the turbine performance, which encircles the turbine and is attached to the tip, was investigated as an additional experiment. However, its device was not effective in improving the turbine characteristics.展开更多
文摘A Wells turbine for wave power conversion has hysteretic characteristics in a reciprocating flow. The hysteretic loop is opposite to the well-known dynamic stall of an airfoil. In this paper, the mechanism of the hysteretic behavior was elucidated by an unsteady 3-dimensional Navier-Stokes numerical simulation. It was found that the hysteretic behavior was associated with a streamwise vortical flow appearing near the blade suction surface. The effects of hub-to-tip ratio and tip clearance on the hysteretic characteristics of the Wells turbine have also been discussed in this paper.
文摘In order to improve the performance of the Wells turbine for wave energy conversion, the effect of end plates on the turbine characteristics has been investigated experimentally by model testing under steady flow conditions. The end plate attached to the tip of the original rotor blade is slightly larger than the original blade profile. The characteristics of the Wells turbine with end plates have been compared with those of the original Wells turbine, i.e., the turbine without end plate. As a result, it has been concluded that the characteristics of the Wells turbine with end plates are superior to those of the original Wells turbine and the characteristics are dependent on the size and position of end plate. Furthermore, the effect of annular plate on the turbine performance, which encircles the turbine and is attached to the tip, was investigated as an additional experiment. However, its device was not effective in improving the turbine characteristics.
