水平轴海流能水轮机的多目标优化设计

能量捕获效率和轴向水推力系数是海流能水轮机转轮的2个重要性能参数.提出了一种水平轴海流能水轮机转轮的多目标优化设计方法.首先采用贝塞尔曲线参数化技术将海流能水轮机转轮叶片节距角分布曲线进行参数化;然后选取转轮的能量捕获效率和轴向水推力系数作为目标函数,并根据BBD试验设计方法和响应面技术建立设计变量和2个目标函数之间的二次多项式响应关系;最后采用NSGA-Ⅱ多目标遗传算法作为优化算法,以叶片节距角分布曲线控制参数为设计变量,以能量捕获效率和轴向水推力系数作为目标函数,以设计变量与目标函数之间的响应关系作为个体适应度评价函数,对海流能转轮进行优化.优化后,叶轮的轴向水推力系数降低了2%,同时能量捕获效率提高了0.4%,证明了所采用的优化方法的有效性.

Multi-objective optimization design of horizontal-axis marine current turbine

Power coefficient and axial thrust coefficient are two important performance parameters of a marine current turbine. Thus a multi-objective optimization design method was proposed to optimize those coefficients for a horizontal-axis marine current turbine. Firstly,the pitch angle distribution curve of the turbine was parameterized by using a Bezier curve; and then the power coefficient and axial thrust coefficient were selected as the objective function,the levels of design factors were decided by the Box- Behnken experimental design method,and a 2nd polynomial relationship between the factors and the objective function was established by making use of response surface technology. At last,the turbine pitch angle curve was optimized by employing NSGA- Ⅱ algorithm. In the optimization power coefficient and axial thrust coefficient were specified as the objective function,and the determined response surface was used as the individual fitness. It was demonstrated that the thrust coefficient was decreased by 2% and the power coefficient was increased by 0. 4% for the optimized turbine. This confirmed the effectiveness of the optimization method proposed here.