潮流能自由变偏角水轮机自启动特性分析

垂直轴水轮机的启动特性是潮流能发电技术的关键问题之一.根据模型试验技术,测量潮流能自由变偏角水轮机转速和转矩在启动过程中的变化规律.基于黏性CFD数值模拟方法,监测该水轮机水动力转矩、负载转矩、叶片偏角、叶片切向力等参数在启动过程中的变化规律.通过分析上述运动参数与动力参数之间的相互作用探讨该水轮机启动特性.研究结果表明:自由变偏角水轮机由于能够迅速调整叶片偏角,因此可以改善水轮机启动过程的总体水动力性能;转矩-速比特性决定该水轮机启动过程经历起步、加速和渐进稳定3个阶段;当发生超载或者受到波浪影响时,水轮机将从渐进稳定段进入不能稳定运行的加速段,继而发生快速停机现象.

Self-Starting Characteristics of Free Variable-Pitch Vertical Axis Tidal Turbine

The starting characteristics of vertical axis turbine are key issues for tidal current energy generation tech- nology. In starting process, the speed and torque of free variable-pitch vertical axis tidal turbine were measured by model test. Meanwhile, hydrodynamic torque, load torque, blade pitch, tangential force and other parameters were monitored based on the viscous CFD numerical simulation. The self-starting characteristics were studied by analyzing the interaction between the motion parameters and dynamic parameters of the turbine. Results showed that the overall hydrodynamic performance can be improved in starting process by adjusting pitch quickly. The starting process is determined by torque-TSR characteristics, and it experiences three stages, including starting, accelerating and asymptotically stable stages. The turbine will operate from asymptotically stable stage to accelerating stage when overloading or wave occurs, and then shutdown happens rapidly.