垂直轴风轮的二维气动特性数学建模与分析

发布时间：2018-12-09 11:09

【摘要】：风能是一种清洁的可再生能源,是全球能源结构中的重要组成部分,其对环境保护、维持生态平衡、减少对传统能源的依赖和改善能源结构都有重要意义。垂直轴风力机相比于水平轴风力机有许多优势:结构简单、安装维护方便、无需对风装置等。而由于垂直轴风轮气动特性复杂:来流穿过风轮时速度、压力等随时间不停变化,如何建立反映其物理本质的数学模型并寻求高效率、高准确度的设计依据,以提高风能利用率已成为垂直轴风力机设计领域的关键科学问题。首先,本文介绍了垂直轴风力机的几种基本研究方法,包括计算空气动力学方法、数值方法和试验方法,重点介绍了动量方法中的多流管模型方法和双多流管模型方法,为下面二维模型的建立提供理论依据。其次,基于叶素动量理论,通过分析阻力型垂直轴风轮凸凹面叶片的受力状况,理解其工作原理,从而建立阻力型垂直轴风轮的二维气动特性的数学模型,给出了阻力型垂直轴风轮平均功率的计算公式,并由此模型分析了阻力型垂直轴风轮的性能提升方法;此外,通过充分分析风轮叶素的受力状态及速度矢量关系,建立了H型垂直轴风轮的二维气动模型并给出了其平均功率计算公式,然后分析了攻角随方位角的变化规律,以及叶尖速比等参数的变化对风轮性能的影响;最后,根据双多流管模型,建立了垂直轴风轮的二维气动特性模型,并将模型在MATLAB软件中进行程序实现以减少其计算量,并以一种3叶片H型风轮为例对模型进行了验证,结果表明模型对垂直轴风轮的设计及功率预测都是实用有效的。最后,对前面给出的算例进行了二维数值模拟,先利用CAD软件画出其几何模型,然后在CFD软件中使用非结构的三角形网格对风轮进行离散化处理,最后在Fluent软件中利用滑移网格的方法分析了其流场特性。通过数值模拟,进一步验证了所建立的垂直轴风轮二维气动特性的数学模型的准确性。
[Abstract]:Wind energy is a kind of clean renewable energy, which is an important part of the global energy structure. It is of great significance for environmental protection, maintaining ecological balance, reducing dependence on traditional energy and improving energy structure. Compared with horizontal axis wind turbine, vertical axis wind turbine has many advantages: simple structure, convenient installation and maintenance, no need for wind equipment, etc. Because the aerodynamic characteristics of vertical axis wind turbine are complicated, such as velocity, pressure and so on, how to establish mathematical model to reflect its physical essence and to find the design basis of high efficiency and high accuracy. Improving wind energy utilization rate has become a key scientific problem in the field of vertical axis wind turbine design. Firstly, this paper introduces several basic research methods of vertical axis wind turbine, including computational aerodynamics method, numerical method and test method, and focuses on the multi-flow tube model method and double multi-flow tube model method in the momentum method. To provide the theoretical basis for the establishment of the following two-dimensional model. Secondly, based on the vane momentum theory, by analyzing the force condition of the resistance vertical axis wind turbine blade, and understanding its working principle, the mathematical model of the two dimensional aerodynamic characteristics of the resistance vertical axis wind turbine is established. The calculation formula of the average power of the resistance vertical axis wind turbine is given, and the performance lifting method of the resistance vertical axis wind turbine is analyzed by using the model. In addition, by fully analyzing the force state and velocity vector relation of wind turbine impeller, a two-dimensional aerodynamic model of H-type vertical axis wind turbine is established and its average power calculation formula is given. Then, the variation law of attack angle with azimuth angle is analyzed. The influence of the blade tip speed ratio and other parameters on the performance of the wind turbine; Finally, a two-dimensional aerodynamic model of a vertical axis wind turbine is established based on a double-flow tube model. The model is programmed in MATLAB software to reduce the computational complexity. The model is verified by a 3-blade H-type wind turbine. The results show that the model is practical and effective for the design and power prediction of vertical axis wind turbines. Finally, the two-dimensional numerical simulation is carried out for the example given above. First, the geometric model is drawn by using CAD software, and then the unstructured triangular mesh is used to discretize the wind turbine in CFD software. Finally, the flow field characteristics are analyzed by slip grid method in Fluent software. Through numerical simulation, the accuracy of the established mathematical model of two-dimensional aerodynamic characteristics of vertical axis wind turbine is further verified.
【学位授予单位】：河南科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM315

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