潮流能水平轴水轮机在剪切来流下的水动力分析

Hydrodynamic Analysis for Horizontal Tidal Turbine in Shear Flow

采用基于计算流体力学方法的全尺度数值模拟计算,建立了适用于潮流能水轮机模拟的剪切来流环境,通过数值计算结果,对潮流能水轮机随时间变化的宏观力和流场特征进行了系统分析,探索水轮机在复杂工况下的水动力特性规律。结果表明,水轮机整个叶轮的总体平均受力在剪切流工况中未受到明显影响;单个叶片的瞬态轴向力系数和瞬态轴向扭矩系数在旋转周期内出现了明显的周期性变化,且周期性变化幅值随转速增大而增大;非定常的瞬时轴向扭矩和力的周期性振荡容易引起单个叶片的结构性振动,可能对水轮机的机械结构造成影响。

A full-scale numerical simulation based on the computational fluid dynamics was used to establish a shear flow environment suitable for simulation of tidal turbine.Based on numerical calculation results,the macroscopic force and the flow field characteristics of tidal turbine over time were systematically analyzed for exploring the hydrodynamic characteristics of the turbine under complex working conditions.The results show that the overall average force of the entire impeller of the turbine is not significantly affected under the shear flow conditions;the transient axial force coefficient and the transient axial torque coefficient of a single blade present obvious periodic variation during the rotation period,which will be also enlarged with the increase of the rotational speed;structural vibration of a single blade is prone to be occurred by an unsteady transient axial torque and periodic oscillation of force,which may bring influence to the mechanical structure of the turbine.