【作者】 王峰；

【导师】 张亮；

【作者基本信息】 哈尔滨工程大学 ， 船舶与海洋结构物设计制造， 2014， 硕士

【摘要】 海洋是蕴藏着庞大资源的能量宝库,海洋能不但清洁环保,对生态环境影响甚微,且是一种取之不尽用之不竭的可再生绿色资源,人类所用能源的未来就在宽广的海洋之中。潮流能水轮机是将潮流动能转换为电能的装置,其中固定偏角垂直轴潮流能水轮机对不同的来流方向具有良好的适应性,且易于加工,成本较低,因而引起了广泛的关注。单层叶片垂直轴水轮机自启动困难、叶轮载荷波动大及低转速时效率低的缺点,影响了它的发展优势。因此,本文在传统固定偏角直叶片水轮机的内部增加一层叶片,应用CFD数值模拟方法,研究这种内外双层固定偏角直叶片垂直轴水轮机的性能。首先对单层垂直轴水轮机进行了二维数值模拟计算,通过与试验结果对比验证了数值模拟的正确性。在此基础上计算得到了单层垂直轴水轮机最佳密实度范围,及最佳叶片数,从而确定了内外双层垂直轴水轮机外层叶轮的尺寸。然后,采用二维和三维CFD数值模拟分析了速比、内外叶轮相位差、半径比、弦长比、展长比、内层叶片翼型及偏角、三维效应等参数对水轮机性能的影响。研究结果表明双层叶轮可有效提高水轮机的自启动性能和低转速下的效率,同时减小了叶片和叶轮的受力和转矩波动。最后,论文还对内外双层水轮机进行了单向流固耦合分析。计算结果表明,内层叶轮的受力状态要明显优于外层叶轮;水轮机的叶片变形量远小于主轴变形量;水轮机整体的最大应力出现在主轴根部,经过校核其结构是安全的。同时由于水轮机整体变形较小,因此无需对双层水轮机进行双向流固耦合分析。研究结果可为内外双层水轮机设计与优化提供借鉴。更多还原

【Abstract】 The ocean is an energy treasure which reserves vast resources. The ocean energy is not only clean and green,but also has little impact on the ecological environment. As a kind of inexhaustible renewable green resources,human’s future of energy is in the wide ocean. Tidal current turbine is the device which can convert tidal current energy to electrical power.Single-decker fixed-pitch vertical axis tidal turbine has a good adaptability to the different flow directions and because of ease of manufacture and low cost, it has attracted wide attention. Single-decker vertical axis tidal turbine has some shortcomings, such as difficulty of self-starting, heavy fluctuations of the impeller load and low efficiency at low speed, which hinders its development. Thus, the paper adds an internal layer to the traditional single-decker fixed-pitch vertical axis turbine. By applying CFD numerical simulation, the performance of this kind of double-decker vertical axis tidal turbine is studied.Based on two dimensional numerical simulations, the paper firstly calculates single vertical axis tidal turbine. Comparing with the experimental results,the numerical simulation is proved to be correct. On the basis of this, the optimum range of solidity and number of blades of single vertical axis tidal turbine are obtained. By this way the size of external impeller of double-decker vertical axis tidal turbine is determined. Then, a series of two-dimensional and three-dimensional CFD numerical simulations are carried out to analyze the influence of different parameters on turbine ’s performance. The parameters conclude speed ratio, azimuth difference between I&E impeller, radius ratio between I&E impeller,chord length ratio between I&E blades, internal blade airfoil, internal blade helix angle,three-dimensional effect, span ratio between I&E blades and so on. According to CFD numerical simulation, the type can effectively improve the turbine’s capable of self-starting and the efficiency at the low speed, and reduce the force fluctuations and torque fluctuations on the blades and impeller.Finally, the paper carries out one-way fluid structure interaction (FSI) simulation on double-decker vertical axis tidal turbine. The results show that the stress state of internal impeller is better than that of external impeller. Considered turbine deformation, the amount of blades deformation is much less than main axis deformation. The maximum of the whole turbine’s stress occurs at the root of the main axis, strength check proves the structure is safe.As the total deformation of turbine is small,two-way FSI simulation is not necessary. All of above could provide reference to design and manufacture of double-decker vertical axis tidal turbine.更多还原