基于水下系留平台的海流能发电装置关键技术研究

发布时间：2018-04-28 12:26

本文选题：水下系留平台 + 海流能　；参考：《西北工业大学》2016年博士论文

【摘要】：水下系留平台是一种投放在海洋中依靠锚链直接与海底相联接的水下平台,在军事防御、海洋资源调查等军民两方面有广泛的应用。为了实现实时监测、侦察的能力,水下系留平台必须具备长时间水下连续工作的能力,水下工作时间是衡量水下系留平台性能的一个重要指标。但是目前水下系留平台都采用自带电池供电,但受体积尺寸、重量的限制,携带能源是有限的,极大限制了水下系留平台的水下连续工作能力。本文以探索研究水下系留平台水下能源补给为主要目的,提出基于水下系留平台的海流能发电装置方案,利用海流能作为原动力,并将之转换为可供水下系留平台使用的持续电能。在广泛查阅和研读国内外相关文献的基础上,采用数值模拟与理论计算研究相结合的方法,围绕基于水下系留平台的海流能发电装置方案、海流发电叶轮水动力性能、叶轮-平台耦合运动性能等关键技术问题展开初步探索性研究,本文主要研究成果及创新性点表现在以下几个方面:(1)水下系留平台海流能发电装置小型化方案设计。首先根据水下系留平台的特殊性,提出了适用于水下系留平台的海流能发电装置技术指标;按照技术指标,提出了两种适用于水下系留平台的伸缩式海流能发电装置,分别为垂直轴式和水平轴式;利用叶素-动量理论优化设计了一种适用于低流速、小型化的海流发电叶片;提出了利用磁力耦合器进行叶轮力矩传输的方案,有效解决叶轮转轴的水下密封问题,通过磁力场仿真验证了磁力耦合器进行力矩传输的可行性。(2)垂直轴海流发电叶轮水动力性能研究。建立了适用于计算垂直轴海流发电叶轮的CFD仿真模型,详细介绍了计算域划分、边界条件设置、计算网格划分以及CFD求解设置策略;着重分析计算了网格密度、仿真步长以及湍流模型对叶轮非定常计算结果的影响,通过对比已有的实验数据,总结出一套高精度的数值模型设置参数;在此基础上,对比分析了不同叶片弧度、叶片张开角度对叶轮平均水动力性能(推力、侧向力、扭矩和功率)的影响;借助于流场可视化技术,分析了叶轮转速、叶片张开角度对叶轮瞬时水动力性能的影响机理。(3)水平轴海流发电叶轮水动力性能研究。首先对静态叶轮进行定常数值仿真,对比几种不同叶片的叶轮在特定海况下的水动力性能,选出性能最优的叶片作为非定常数值仿真的对象;之后针对复杂工况下的水平轴海流发电叶轮,通过非定常CFD建模仿真,对比研究叶轮尖速比、叶轮展开长度、平台姿态角以及湍流强度等影响因素对叶轮水动力性能和尾流场分布的影响。(4)水下系留平台耦合运动性能研究。平台姿态变化对叶轮发电性能有明显影响,因此有必要分析叶轮-平台系统耦合运动的稳定性。首先基于Newton-Euler法建立了水下系留平台主体的六自由度动力学模型;考虑到水下系留平台在海洋环境的作用下处于一种大攻角下的微速分离流动状态,利用CFD技术分析水下系留平台大攻角绕流下的流体动力特性,得到大攻角下水下系留平台的各水动力参数;根据数值计算结果对叶轮周期性水动力进行拟合,得到叶轮周期性扰动力模型;根据集中质量法建立了水下锚揽的三维动力学模型,引入锚链首端和末端的动力学和运动学耦合条件,建立整个水下系留平台的耦合动力学模型;基于系统耦合动力学模型,分析比较了平台重浮力配置、锚缆长度、叶轮伸出位置以及海流流速等参数对叶轮-平台系统耦合运动性能的影响。
[Abstract]:The underwater tethered platform is a kind of underwater platform which is directly connected with the seabed by the anchor chain in the ocean. It is widely used in two aspects, such as military defense, marine resources investigation and so on. In order to realize real-time monitoring and reconnaissance, the underwater tether must have the ability to work continuously under water for long time and underwater working time. It is an important index to measure the performance of the underwater tethered platform. But at present, the underwater tethered platform is powered by the battery with its own battery, but limited by the size and weight, the energy is limited, which greatly restricts the continuous working ability of the underwater tethered platform. The purpose of this paper is to propose a scheme of the current energy generating unit based on the underwater tethered platform, using the current energy as the original power and converting it into the continuous electric energy used by the tethered platform for water supply. Based on the extensive reference and study of the related literature at home and abroad, the method of combining numerical simulation and theoretical calculation research is adopted, which is based on the underwater base. The preliminary exploratory research on the key technical problems of the current power generation device of the tethered platform, the hydrodynamic performance of the ocean current power turbine and the coupling motion of the impeller and the platform is carried out. The main research results and the innovative points in this paper are as follows: (1) the design of miniaturization of the underwater tethered flat sea power generation unit. According to the particularity of the underwater tethered platform, the technical index of the current energy generating unit suitable for underwater tethered platform is put forward. According to the technical indexes, two kinds of telescopic current energy generating units for underwater tethered platform are proposed, which are vertical axis and horizontal axis, and a kind of optimum design is designed by using the leaf element momentum theory. Flow velocity, miniaturized current power generation blade; proposed a scheme using magnetic coupler to carry out impeller torque transmission, effectively solving the problem of underwater seal of impeller rotating shaft. Through magnetic field simulation, the feasibility of torque transmission of magnetic coupler was verified. (2) research on hydrodynamic performance of vertical axis current turbine. In this paper, the CFD simulation model of a vertical axis current impeller is calculated. The calculation domain division, boundary condition setting, calculation grid division and CFD solution setting strategy are introduced in detail. The grid density, the simulation step and the turbulence model on the unsteady calculation results of the impeller are analyzed and calculated, and a set of experiments is made to sum up a set of experimental data. On this basis, the effects of different blade radians and blade opening angles on the average hydrodynamic performance (thrust, lateral force, torque and power) of the impeller were compared and analyzed on this basis. With the aid of flow visualization technology, the influence mechanism of impeller speed and blade opening angle on the instantaneous hydrodynamic performance of the blade wheel was analyzed. (3) The hydrodynamic performance of a horizontal axis current impeller is studied. First, the steady numerical simulation of the static impeller is carried out to compare the hydrodynamic performance of the impeller with different blades in a specific sea condition. The optimal blade is selected as the object of the unsteady numerical simulation. CFD modeling and simulation are used to compare the influence of impeller tip speed ratio, impeller expansion length, platform attitude angle and turbulence intensity on the hydrodynamic performance and wake distribution of the impeller. (4) study on the coupling motion performance of the underwater tethered platform. The attitude changes of the platform have a significant influence on the performance of the impeller power generation. The stability of the coupled motion of the platform system. First, based on the Newton-Euler method, a six degree of freedom dynamic model of the main body of the underwater tethered platform is established. Considering the micro velocity separation flow under a large angle of attack under the action of the marine environment under the action of the ocean environment, the fluid under the large angle of attack under the water mooring platform is analyzed by the CFD technology. The dynamic characteristics are obtained, and the hydrodynamic parameters of the subsewer platform are obtained at large angle of attack. According to the numerical results, the periodic hydrodynamic forces of the impeller are fitted, and the periodic dynamic model of the impeller is obtained. The three-dimensional dynamic model of the underwater anchor is established according to the centralized mass method, and the dynamic and kinematic coupling strips at the head end and the end of the anchorage chain are introduced. The coupling dynamic model of the entire underwater tethered platform is established, and based on the system coupling dynamic model, the effects of the parameters of the platform heavy buoyancy, the length of the anchor cable, the position of the impeller and the current flow velocity on the coupled motion performance of the impeller and platform system are analyzed and compared.

【学位授予单位】：西北工业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TM612;P743.1

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