In order to increase the performance of horizontal tidal turbines, a multi-objective optimization model was proposed in this study. Firstly, the prediction model for horizontal tidal turbines was built, which coupled ...In order to increase the performance of horizontal tidal turbines, a multi-objective optimization model was proposed in this study. Firstly, the prediction model for horizontal tidal turbines was built, which coupled the blade element momentum (BEM) theory and the CFD calculation. Secondly, a multi-objective optimization method coupled the response surface method (RSM) with the multi-objective genetic algorithm NSGA-II was applied to obtain the optimal blade profiles. The pitch angle and the chord length distribution were chosen as the design variables, while the mean power coefficient and the variance of power coefficient were chosen as the objective functions. With the mean power coefficient improved by 4.1% and the variance of power coefficient decreased by 46.7%, results showed that both objective functions could be improved.展开更多
为研究艇后非均匀流场中大侧斜螺旋桨无空泡负载噪声的分布规律,文章采用"CFD+BEM"法,以SUBOFF潜艇后某大侧斜桨为研究对象,首先稳态计算均匀进流下螺旋桨敞水特性,模拟系数值与实验误差在3%以内,验证了CFD数值计算的可信性...为研究艇后非均匀流场中大侧斜螺旋桨无空泡负载噪声的分布规律,文章采用"CFD+BEM"法,以SUBOFF潜艇后某大侧斜桨为研究对象,首先稳态计算均匀进流下螺旋桨敞水特性,模拟系数值与实验误差在3%以内,验证了CFD数值计算的可信性。然后采用大涡(LES)模拟,对"艇+桨"进行三维非定常数值模拟,计算得到桨表面声偶极子数据后,通过距离加权平均法映射到声网格节点上,将噪声源直接分布在桨叶表面上进行积分来预报螺旋桨的低频线谱噪声。采用边界元法基于扇声源理论通过FW-H声类比方程分别在1 k Hz以内对桨盘面、轴向纵剖面及10倍桨半径球场的噪声进行频域求解。研究表明:桨盘面和轴向纵剖面上声指向均呈8字形,但受螺旋桨自身旋转及大侧斜的存在,指向性不唯一;球场声场显示,轴向声辐射面较大,声辐射强,径向辐射面小且辐射较弱;特征点的计算结果显示,高阶叶频声压级明显比一阶叶频低,这与物理现象相符,将特征点处结果与已发表文献进行对比,吻合性良好,并对存在的差异作出了合理的物理解释。该文为螺旋桨噪声预报介绍了一种可行的新方法。展开更多
潮流能作为一种清洁无污染而且蕴藏丰富的可再生新能源,对其合理开发利用可以有效缓减能源短缺的问题。文中选用N A C A 644X X系列翼型,以得到较高捕能系数的水轮机为目标,基于叶素-动量(B EM)理论,给出了叶轮叶片设计的步骤,分别以翼...潮流能作为一种清洁无污染而且蕴藏丰富的可再生新能源,对其合理开发利用可以有效缓减能源短缺的问题。文中选用N A C A 644X X系列翼型,以得到较高捕能系数的水轮机为目标,基于叶素-动量(B EM)理论,给出了叶轮叶片设计的步骤,分别以翼型前缘和翼型最大厚度为基准设计出两种30 W的小型水平轴潮流能水轮机叶片;然后运用叶素理论和动量理论对叶轮捕能系数进行了理论计算,即运用C FD软件A N SY S C FX对设计出的叶轮模型捕能系数进行了数值模拟计算并与理论值进行了对比。结果表明以翼型前缘为基准设计出的叶片捕能效果更好,同时验证了叶素理论与动量理论的等效性以及运用叶素-动量理论进行叶片设计的有效性。展开更多
The present work is based on the comparative study between “Blade-Element- Momentum” (BEM) analysis and “Computational-Fluid-Dynamics” (CFD) analysis of small-scale horizontal axis wind turbine blade. In this stud...The present work is based on the comparative study between “Blade-Element- Momentum” (BEM) analysis and “Computational-Fluid-Dynamics” (CFD) analysis of small-scale horizontal axis wind turbine blade. In this study, the pitch is considered as fixed and rotor speed is variable. Firstly, the aerodynamic characteristics of three different specialized airfoils were analyzed to get optimum design parameters of wind turbine blade. Then BEM was performed with the application of the open source wind turbine design and performance computation software Q-Blade v0.6. After that, CFD simulation was done by Ansys CFX software. Here, k-ω “Shear-Stress-Transport” (SST) model was conducted for three-dimensional visualization of turbine performance. However, the best coefficient of performance was observed at 6o angle of attack. At this angle of attack, in the case of BEM, the highest coefficient of performance was 0.47 whereby CFD analysis, it was 0.43. Both studies showed good performance prediction which was a positive step to accelerate the continuous revolution in wind energy sector.展开更多
基金financially supported by the National Natural Science Foundation of China(Grant Nos.51706198 and 51839010)the Zhejiang Provincial Natural Science Foundation of China(Grant No.LQ17E090004)
文摘In order to increase the performance of horizontal tidal turbines, a multi-objective optimization model was proposed in this study. Firstly, the prediction model for horizontal tidal turbines was built, which coupled the blade element momentum (BEM) theory and the CFD calculation. Secondly, a multi-objective optimization method coupled the response surface method (RSM) with the multi-objective genetic algorithm NSGA-II was applied to obtain the optimal blade profiles. The pitch angle and the chord length distribution were chosen as the design variables, while the mean power coefficient and the variance of power coefficient were chosen as the objective functions. With the mean power coefficient improved by 4.1% and the variance of power coefficient decreased by 46.7%, results showed that both objective functions could be improved.
基金Supported by National Nature Science Foundation of China(51009144)
文摘为研究艇后非均匀流场中大侧斜螺旋桨无空泡负载噪声的分布规律,文章采用"CFD+BEM"法,以SUBOFF潜艇后某大侧斜桨为研究对象,首先稳态计算均匀进流下螺旋桨敞水特性,模拟系数值与实验误差在3%以内,验证了CFD数值计算的可信性。然后采用大涡(LES)模拟,对"艇+桨"进行三维非定常数值模拟,计算得到桨表面声偶极子数据后,通过距离加权平均法映射到声网格节点上,将噪声源直接分布在桨叶表面上进行积分来预报螺旋桨的低频线谱噪声。采用边界元法基于扇声源理论通过FW-H声类比方程分别在1 k Hz以内对桨盘面、轴向纵剖面及10倍桨半径球场的噪声进行频域求解。研究表明:桨盘面和轴向纵剖面上声指向均呈8字形,但受螺旋桨自身旋转及大侧斜的存在,指向性不唯一;球场声场显示,轴向声辐射面较大,声辐射强,径向辐射面小且辐射较弱;特征点的计算结果显示,高阶叶频声压级明显比一阶叶频低,这与物理现象相符,将特征点处结果与已发表文献进行对比,吻合性良好,并对存在的差异作出了合理的物理解释。该文为螺旋桨噪声预报介绍了一种可行的新方法。
文摘潮流能作为一种清洁无污染而且蕴藏丰富的可再生新能源,对其合理开发利用可以有效缓减能源短缺的问题。文中选用N A C A 644X X系列翼型,以得到较高捕能系数的水轮机为目标,基于叶素-动量(B EM)理论,给出了叶轮叶片设计的步骤,分别以翼型前缘和翼型最大厚度为基准设计出两种30 W的小型水平轴潮流能水轮机叶片;然后运用叶素理论和动量理论对叶轮捕能系数进行了理论计算,即运用C FD软件A N SY S C FX对设计出的叶轮模型捕能系数进行了数值模拟计算并与理论值进行了对比。结果表明以翼型前缘为基准设计出的叶片捕能效果更好,同时验证了叶素理论与动量理论的等效性以及运用叶素-动量理论进行叶片设计的有效性。
文摘The present work is based on the comparative study between “Blade-Element- Momentum” (BEM) analysis and “Computational-Fluid-Dynamics” (CFD) analysis of small-scale horizontal axis wind turbine blade. In this study, the pitch is considered as fixed and rotor speed is variable. Firstly, the aerodynamic characteristics of three different specialized airfoils were analyzed to get optimum design parameters of wind turbine blade. Then BEM was performed with the application of the open source wind turbine design and performance computation software Q-Blade v0.6. After that, CFD simulation was done by Ansys CFX software. Here, k-ω “Shear-Stress-Transport” (SST) model was conducted for three-dimensional visualization of turbine performance. However, the best coefficient of performance was observed at 6o angle of attack. At this angle of attack, in the case of BEM, the highest coefficient of performance was 0.47 whereby CFD analysis, it was 0.43. Both studies showed good performance prediction which was a positive step to accelerate the continuous revolution in wind energy sector.
