竖轴潮流能水轮机水动力性能的研究与实验

发布时间：2018-08-01 08:39

【摘要】：化石燃料的大量使用造成了环境恶化和常规能源枯竭,世界各国都在寻找替代能源。与其他类型的替代能源相比,潮流能拥有可再生、可预测、对环境和视觉的影响较小等优势,获得了广泛的重视。潮流能水轮机是从潮流中提取能量的装置。根据结构形式,潮流能水轮机可分为竖轴水轮机和水平轴水轮机。相比水平轴水轮机,竖轴水轮机有一些独特的优势,如工作不受流向影响、维护简单、发电机舱不影响水轮机流场、噪声低不易空化等,吸引了许多学者的注意。但也有一些问题阻碍了竖轴水轮机的应用,如较差的自启动性能、相对低的获能效率、输出脉动等。本文针对竖轴水轮机获能效率低、自启动性能差、输出及荷载脉动的缺点,通过数值模拟与物理模型试验研究了水轮机叶片端部涡流、不同水轮机叶片排列形式、水轮机加装流体增速装置的水动力特性。成果应用在15 kW竖轴潮流能试验装置上并进行了实海况试验,获得了较好的效果。本文主要内容如下:通过三维机翼理论研究了水轮机叶片端部涡流的产生机理与影响因素,探索在水轮机叶片端部加装端板来抑制叶片端部涡流、进而提升水轮机获能的改进方法。通过物理模型试验和数值模拟(Ansys Fluent软件)研究了三叶片水轮机的水动力特性,基于叶片旋转过程中端部涡流的影响范围设计了端板形状,通过数值模拟与物理模型试验验证了加装端板提升水轮机获能的有效性。在完整端板形状的基础上将端板减半,通过减阻和调节叶片两侧压力分布来进一步提升水轮机性能。以数值模拟研究了水轮机加装内半边与外半边端板时的水动力性能,分析了加装内半边与外半边端板时水轮机叶片的输出特性与作用机理。以物理模型试验方法研究了不同叶片数的单层叶片水轮机获能效率随尖速比变化规律,通过计算水轮机在不同停止位置时的水动力转矩来判断水轮机的自启动性能。使用耦合式数值模拟方法研究了一种新式的双层六叶片水轮机的水动力性能,分析了其内层叶片半径及相位差角变化时对水轮机获能、负载特性和自启动性能的影响。以数值模拟研究了不同扭转角同轴双转子水轮机的自启动性能、获能效率及输出特性,并与同展长的三叶片水轮机进行了比较。基于不同形式水轮机的性能特点,对其适用范围进行了分析。基于导流罩和扩散器原理设计了结构简单、易于建造且适应往复流向的聚流增速装置,通过数值模拟与物理模型试验研究了其在水槽中的增速效果,并进行了二维、三维开敞环境的数值模拟,以使结果具有普遍性。基于三维开敞环境的数值模拟结果,分析了不同流向时扩张板长度与角度变化对增速装置内部增速效果的影响,以及增速装置所受轴向力的大小。使用耦合式数值模拟方法研究了三叶片水轮机加装增速装置前后水轮机运转尖速比区间、水轮机获能效率、负载特性及叶片输出沿方位角分布的变化,并分析了扩张板角度与长度变化对水轮机性能的影响。在实际海域对一台采用60°扭转角同轴双转子水轮机、装机容量为15 kW的竖轴潮流能发电装置性能进行测试。基于海试数据,分析了水轮机的运转尖速比区间及最优尖速比,高潮位与低潮位期间的平均获能效率、发电量及对应潮流周期的容量因数,自启动流速的分布,及系统获能效率随流速的变化。海试后期在水轮机展向一侧加装了增速装置,分析了加装增速装置后水轮机的性能变化。通过二维数值模拟研究了隔流板及支撑桩柱对水轮机性能的影响,及由水轮机运转诱导引起的流速测量偏差,并对水轮机性能进行修正估算。海试过程中观察到波浪作用和海洋生物附着可能对潮流能机组的运行产生威胁,流速脉动和水轮机负载调控失效会造成水轮机停机,在未来潮流能发电项目的设计建造及运行过程中应予以注意。
[Abstract]:The large use of fossil fuels has caused environmental degradation and the depletion of conventional energy. All countries in the world are looking for alternative energy. Compared with other types of alternative energy, the power flow can be regenerated, predictable, and less affected on the environment and vision. According to the structure form, the power flow turbine can be divided into vertical shaft turbine and horizontal shaft water turbine. Compared with horizontal axis water turbine, vertical shaft water turbine has some unique advantages, such as the work is not affected by the flow direction, maintenance is simple, the generator cabin does not affect the flow field of the turbine, the noise is low and it is not easy to cavitation, but it has attracted the attention of many scholars. But there is also a lot of attention. Some problems impede the application of vertical shaft turbine, such as poor self starting performance, relatively low energy efficiency, output pulsation, etc. This paper aims at the shortcomings of low energy efficiency, poor self starting performance, and output and load pulsation of vertical shaft turbines. Through numerical simulation and physical model test, the eddy current at the end of turbine blades and different turbine blades are studied by numerical simulation and physical model test. The hydrodynamic characteristics of the hydraulic turbine with a fluid speed increase device are applied to the hydraulic turbine. The results are applied to the 15 kW vertical axis power flow test device and the actual sea condition test is carried out. The main contents of this paper are as follows: the formation mechanism and influence factors of the vortex at the end of the turbine blade are studied by the three-dimensional wing theory, and the water is explored in the water. At the end of the turbine blade, the end plate is installed to restrain the vortex in the end of the blade and improve the energy of the turbine. The hydrodynamic characteristics of the three leaf turbine are studied by the physical model test and the numerical simulation (Ansys Fluent software). The end plate shape is designed based on the influence range of the end swirl in the process of blade rotation. The simulation and physical model test verify the effectiveness of the installed end plate to improve the energy of the turbine. The end plate is halved on the basis of the complete end plate shape. The hydraulic performance of the turbine is further improved by reducing the resistance and regulating the pressure distribution on both sides of the blade. The hydrodynamic performance of the hydraulic turbine when adding the inner half side and the outer half end plate is studied by numerical simulation. The output characteristics and action mechanism of the turbine blade are analyzed with the inner and outer half side plates. The physical model test method is used to study the change law of the energy efficiency with the tip speed ratio of the single blade turbine with different number of blades. By calculating the hydrodynamic torque of the turbine at different stopping positions, the self starting performance of the turbine is judged. The hydrodynamic performance of a new double deck six blade turbine is studied by the coupled numerical simulation method. The influence of the inner blade radius and the phase difference angle on the power, load and self starting performance of the turbine is analyzed. The self starting performance of the coaxial double rotor hydraulic turbine with different torsional angles is studied by numerical simulation. The efficiency and output characteristics are compared with the three leaf turbine with the same length. Based on the performance characteristics of different types of turbine, the scope of its application is analyzed. Based on the principle of the guide cover and diffuser, a simple structure is designed, which is easy to build and adapts to the flow direction of the reciprocating flow. The numerical simulation and physical model are used. In order to make the result universally, the effect of the length and angle of the expansion plate on the growth rate of the inner part of the speed increase device, as well as the axis of the speed increasing device, are analyzed by numerical simulation of the two-dimensional and three-dimensional open environment. The coupling numerical simulation method is used to study the speed ratio interval of the turbine running tip and the change of the energy efficiency, the load characteristic and the distribution of the blade output along the azimuth angle before and after the installation of the speed increase device of the three leaf blade turbine. The influence of the angle and length of the expansion plate on the performance of the turbine is analyzed. The performance of the vertical axis power flow power generation unit with a 60 degree torsion angle coaxial double rotor and a vertical shaft with a capacity of 15 kW is tested. Based on the sea test data, the average energy efficiency of the speed ratio interval and the optimal tip speed ratio, the average energy efficiency during the high tide and low tide level, the capacity factor of the power generation and the corresponding flow cycle are analyzed. The distribution of dynamic flow velocity and the change of the energy efficiency with the velocity of the system. In the later period of the sea test, the speed increase device was installed on the side of the turbine, and the performance changes of the turbine were analyzed after the acceleration device. The effect of the septum plate and the supporting post column on the performance of the hydraulic turbine and the flow velocity induced by the operation of the hydraulic turbine were studied by the two dimensional numerical simulation. In the process of sea test, it is observed that wave action and marine organism attachment may threaten the operation of the power flow power unit. The flow velocity fluctuation and the control failure of the hydraulic turbine load will cause the turbine to stop, and should be injected during the design, construction and operation of the power generation power generation project in the future. Meaning.
【学位授予单位】：大连理工大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TK730.7

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