潮流能自由变偏角水轮机限位角优化方法

Optimization of limit angle for free variable-pitch vertical axis tidal turbine

针对潮流能水轮机中的水动力问题,采用基于粘性CFD理论的多体耦合数值模拟方法对影响潮流能自由变偏角水轮机水动力性能的重要参数限位角进行研究.通过对比不同限位角下叶片偏角和水轮机转矩变化规律,阐明了限位角对水轮机运动特性和动力特性的影响规律.以水轮机功率最大化为优化目标,提出了限位角参数优化选取方法,并进行了实例验证.研究表明:当叶片摆动到限位角时,偏角由限位角的大小决定,限位角上限和下限对偏角的控制区域不同,这样可以通过单独调节限位角的上限或者下限分别改善叶片在不同方位角处的水动力特性.

In efforts to solve the hydrodynamic problem of tidal turbines, an investigation utilizing a multi-body cou- pling numerical method, based on the theory of viscous CFD is examined. The optimization of the limit angle is the most important factor that influences on the hydrodynamic performance of the free variable-pitch vertical axis tidal turbine. By analyzing the variation of the blade pitch angle and the turbine torque at different limit angles, the effect of the limit angle on the kinematics and dynamics characteristics of the turbine was expounded during this study. The optimization of the limit angle was proposed to maximize the turbine power, and it was verified by an ex- ample. The results showed the pitch angle was decided by the limit angle when turbine blade reached the bounds of limit angle, the control areas of upper and lower limit angle were different, and so hydrodynamic characteristics of tidal turbine at different azimuths can be improved by adjusting the upper or lower limit angle individually.