横轴潮流能水轮机翼型优化

Horizontal Axis Tidal Turbine Hydrofoil Optimization

陈三木

11749083

硕士

力学

万敏平

2019-05-28

2019-07-20

哈尔滨工业大学

深圳

作为一种尚未大规模开发的清洁可再生能源，潮汐能正在越来越引起人们的 关注和重视。预计未来潮流能发电将会在电力市场中扮演越来越重要的角色，潮流能水轮机的发展和应用也将更为完善。 水轮机叶片是获取潮流能的核心部件之一，其水动力性能决定了潮流能发电 机的能量利用率、载荷特性、空化特性及噪声水平等，而决定叶片性能的最主要 因素是构成叶片外形基本要素的翼型。因此，高性能翼型对于提高水轮机叶片潮 流能捕捉能力、降低叶片载荷等有重要意义。为此本文开展了横轴潮流能水轮机 翼型的水动力分析与优化设计方法、横轴潮流能水轮机设计建模及其数值模拟的 研究，主要研究工作如下： 首先进行二维翼型水动力 CFD 模拟。数值计算和网格生成分别应用 Fluent 和 Pointwise，计算应用 C 型网格，并进行网格无关性验证。采用基于 RANS 的 SST k−ω 湍流模型对翼型在各个攻角状态下的绕流进行了水动力分析，与实验结果相 比，小攻角时，结果吻合非常好，综合误差小于1.5%，最大误差为2.82%。这部分 内容主要为翼型优化提供精确的数值校准，为优化平台搭建过程中的重要步骤。 随后对水轮机翼型进行单点、多点优化。采用基于代理模型的单目标、多目 标优化设计方法，根据叶片不同截面处的水动力要求分别在不考虑空化和考虑空 化条件下进行了单攻角、多攻角优化设计，无空化情况下单点优化效果明显，目标 函数提升达 19.61%，多点优化则弥补了单点优化翼型在大攻角时的较差性能，实 现了全攻角范围的性能提升；考虑空化得到的翼型则在优化点附近显著降低了翼 型空化区域面积。对优化前后翼型的水动力性能的对比分析也表明了优化后翼型 性能优异，验证了该优化平台的有效性。 最后通过数值模拟评估水平轴潮流能水轮机水动力性能。首先建立水平轴潮 流能水轮机三维模型，利用 MRF 模型对整机进行稳态计算，验证了该稳态计算方 法结果正确合理且满足准确性，流场分析展示了流场细节。然后以优化前后翼型 分别建立水平轴潮流能水轮机模型，并进行对比计算，结果表明当翼尖速比较小 时，优化后模型具有更高的能量利用效率。

As a clean and renewable energy that has not been developed on a large scale, tidal energy is attracting more and more attention. It is expected that tidal power will play an increasingly important role in the power market in the future, and tidal turbines will also be widely developed and applied. The turbine blades are one of the core components that obtain tidal energy. Its hydrodynamic performance determines the energy utilization, the load characteristics, the cavitation characteristics as well as the noise level of the tidal turbine. And the most important factor that determines the blades’ performance is the shape of the hydrofoil. Therefore, the high-performance hydrofoil is important to improve the turbine capture capability and reduce the blades load. In this paper, the hydrodynamic analysis, optimization design method of the horizontal axis tidal turbine hydrofoil, the design modeling and numerical simulation of horizontal axis tidal turbine are studied. The main researches are as follow: Firstly, carry out CFD simulation of the hydrofoil. Fluent is adopted for numerical simulation, the C-tpye grid is generated by Pointwise. The SST k −ω turbulence model based on RANS was used to analyze the hydrodynamic characteristics of the airfoil flow at different angles of attack. Compared with the experimental results, when the angle of attack is small,the results are perfectly matched, and the comprehensive error is less than 1.5% while the maximum error is 2.82%. This part mainly provides accurate numerical calibration for airfoil optimization and is an critical step in the process of optimizing platform construction. Then the single-point and multi-point optimization of the hydrofoil is carried out. Surrogate-based optimization method is used to establish single-point and multi-point optimization platform. According to the hydrodynamic requirements of the different cross-sections of the blade，carry out the optimization of the single angle of attack and multiple angles of attack considering with or without cavitation. The objective function has been significantly improved in the absence of cavitation single point optimization, reaching 19.61%, while multi-point optimization compensates for the poor performance ofsingle-point optimized airfoil at high angles of attack. While considering cavitation，The airfoil reduces the area of cavitation significantly near the optimization point. Results show that the performance of the optimized airfoils is excellent,which verifies the effectiveness of the platform. Finally,the hydrodynamic performance of the horizontal axis tidal current turbineis evaluated by numerical simulation. Firstly, a three-dimensional model of the horizontal axis tidal turbine is established, MRF model is applied to simulate the turbine in steady state. The results of the steady state simulation are verified to be correct,reasonableand accurate, and the flow field analysis shows more flow field details. Then, the horizontal axis turbine models are built with the original and the optimized airfoils respectively, and the results show that the optimized model has higher energy utilization efficiency when the tip velocity ratio is small.

潮流能 横轴水轮机 翼型优化 CFD 水动力性能

tidal horizontalturbine foiloptimization CFD hyrodynamics

中文

联合培养

南方科技大学

陈三木. 横轴潮流能水轮机翼型优化[D]. 深圳. 哈尔滨工业大学,2019.