漂浮式潮流能装置载体的波浪运动响应使水平轴叶轮的水动力特性发生变化。采用滑移网格及动网格技术对无界均匀来流中旋转叶轮强迫纵摇时的三维水动力特性进行分析,研究不同纵摇频率、纵摇幅值、速比等参数对叶轮水动力的影响规律,以及根据叶轮纵摇运动时的水动力时历曲线,拟合得到叶轮的纵摇阻尼系数。研究表明:叶轮轴向载荷和能量利用率瞬时值产生波动,波动幅值随纵摇频率、纵摇幅值及速比的增大而增大;叶片表面压力分布时刻发生变化,纵摇频率、纵摇幅值及速比越大,变化越明显;纵摇阻尼系数与纵荡频率、振幅无关,而与叶轮旋转速度相关,旋转速度越大,阻尼系数越大。
Under the condition of actual sea state,hydrodynamic characteristic of floating horizontal axis impeller is related to wave characteristics and floating carrier wave motion response. This paper uses slipping mesh and dynamic mesh to analyze the hydrodynamic characteristic in uniform unbounded stream when the rotating impeller is forced to pitch,and studies the influence of different pitch frequencies,pitch amplitudes and tip speed ratios on turbine hydrodynamics. Pitch damping coefficient can be got by hydrodynamic time-history curve of pitching impeller. The results showed that the impeller axial load and energy utilization ratio will make a fluctuation in pitching and the wave amplitude of momentary value increases with the increasing of pitch frequency,pitch amplitude,and tip speed ratio. The blade surface pressure distribution changes when the impeller is pitching,and the larger the pitch frequency,pitch amplitude and tip speed ratio,the more obvious the changes. The frequency and amplitude of the pitch have little impact on damping coefficient,but this coefficient is positively proportional to the rotational speed of the impeller.