海湾相位差潮能研究

发布时间：2018-03-16 04:24

本文选题：相位差　切入点：潮能　出处：《浙江大学》2014年博士论文　论文类型：学位论文

【摘要】：在诸多海洋可再生能源中,潮能储量巨大,可准确预报且能量密度最大,在能源紧缺、资源开发与环境保护矛盾突出的当下,加大对潮能的研究开发力度显得非常必要。论文从理论推导、典型海湾选址、数值模型计算和环境优势分析等方面研究了相位差潮能开发的技术问题。本文首次提出利用海湾潮波相位差的全新潮能开发方式,其原理是：外海潮波向海岸和海湾传播过程中,由于岸线和地形变化导致潮波变形,在海湾内外形成显著的相位差而具有动态水头,并利用这种动态水头进行潮能发电。该潮能开发技术在不建坝截流前提下获得较高的能量密度,具有环境影响较小和资源利用率高的优势。采用两种不同的数学物理方法求得相位差潮能水头解析解。①利用海水运动基本方程和牛顿第二运动定律导出潮能水头解析解；②基于波动理论,分别求得忽略和考虑阻力条件下两组潮能水头解析解,且忽略阻力的解析解是考虑阻力解析解的一个特例。此即相位差潮能研究的理论基础。基于N-S方程获得不同组合条件下的潮能水头数值解,对比数值解和解析解曲线表明,与忽略阻力的解析解不同,考虑阻力的解析结果与数值模型解符合良好。可见本文获得的潮能水头理论公式是合理可靠的,为新型潮能开发提供了技术支撑。根据潮能水头理论计算公式和尾水动能跟水体总势能的关系,得到发电通道内理论最大功率和装机功率的数学表达式,进而得出最佳装机功率Pp-max的计算公式,潮流强度和半岛长度越大、过水面积越大、效率系数越高,装机功率越大。基于潮能水头解析解和最佳装机功率,提出海湾相位差潮能选址的四项原则。选定福建三沙湾为典型潮能海湾进行了为期一年的连续观测,统计得到大潮期最大潮能水头为1.70～2.20m。而由本文公式计算得潮能水头值为1.48m～2.33m,理论计算值与实测值较为接近。研究认为该典型海湾的相位差潮能水头具备开发价值。建立典型海湾二维水动力数值模型,预测了不同发电工况下的水动力场,获得潮位、流速、发电水头和发电流量等要素过程曲线,结果表明：①相位差潮能发电时水头损失较小,对发电效率的影响明显小于传统潮汐能开发；②经发电通道流向湾外的流量较大,正向发电宜指向湾外,以获得更多的电能。基于数值模型成果进行机组选型和发电量计算,认为该海湾适宜装机(6-10)Mw。与传统潮能相比,相位差潮能的最大优势在于环境影响小,具体表现为①加快海湾水体交换速率；②降低湾内活性磷酸盐含量,改善海湾水质；③增强湾底水动力；④便于湾底清淤。因而相位差潮能是一种环境友好型海洋能开发方式,为潮能资源开发提供一种新的途径。
[Abstract]:Among the many marine renewable energy sources, the tidal energy has huge reserves, can be accurately predicted and has the largest energy density. At present, when energy is in short supply and the contradiction between resource development and environmental protection is prominent, It is necessary to increase the research and development of tidal energy. This paper studies the technical problems of phase difference tidal energy development from the aspects of theoretical derivation, typical bay location, numerical model calculation and environmental advantage analysis. In this paper, a new way of developing tidal energy by using the phase difference of tidal wave in the bay is proposed for the first time. The principle is that the tidal wave is deformed due to the changes of shoreline and topography in the process of the tide wave spreading to the coast and the bay. The dynamic water head is formed within and outside the bay, and the dynamic water head is used to generate electricity with tidal energy. The technology of tidal energy development can obtain high energy density without dam closure. The utility model has the advantages of small environmental impact and high utilization rate of resources. Two different mathematical and physical methods are used to obtain the analytical solution of the phase difference tide head. 1. The analytical solution of the tidal head is derived from the basic equation of sea water motion and Newton's second law of motion based on the wave theory. The analytical solutions of two groups of tidal energy head under the condition of neglecting and considering the resistance are obtained, and the analytical solution of neglecting the resistance is a special case of the analytical solution of the resistance, which is the theoretical basis of the study of phase difference tidal energy. Based on the N-S equation, the numerical solutions of the tide energy head under different combination conditions are obtained. The comparison of the numerical solution and the analytical solution curve shows that the numerical solution is different from the analytical solution which ignores the resistance. The analytical results of considering resistance are in good agreement with the numerical model. It can be seen that the theoretical formula of tidal energy head obtained in this paper is reasonable and reliable, which provides a technical support for the development of new tidal energy. According to the theoretical calculation formula of tidal head and the relation between the kinetic energy of tail water and the total potential energy of water body, the mathematical expressions of theoretical maximum power and installed power in power generation channel are obtained, and the calculation formula of optimal installed power Pp-max is obtained. The larger the tidal current intensity and the length of the peninsula, the larger the overwater area, the higher the efficiency coefficient and the greater the installed power. Based on the analytical solution of the tidal head and the optimal installed power, four principles for the location of the tidal energy of the bay phase difference are proposed. The Sansha Bay in Fujian Province is selected as the typical tidal energy bay for one year of continuous observation. According to statistics, the maximum tidal energy head in the spring tide period is 1.70 ~ 2.20m.The calculated water head value of this paper is 1.48 m ~ 2.33 m, which is close to the measured value. It is considered that the phase difference tidal energy head of the typical bay is valuable for development. A two-dimensional hydrodynamic numerical model of typical bay is established to predict the hydrodynamic field under different power generation conditions, and obtain the process curves of tidal level, velocity of power, water head and flow rate of power generation, etc. The results show that the head loss of water head is smaller than that of the traditional tidal energy development, which is smaller than that of the traditional tidal energy development, and the flow through the generation channel to the outside of the bay is larger, and the forward power generation should be directed to the outside of the bay. In order to obtain more electric energy, based on the results of numerical model, the selection of generating units and the calculation of generating power are carried out, and it is considered that the bay is suitable for installing 6-10mw. Compared with the traditional tidal energy, the greatest advantage of the phase difference tidal energy lies in the small environmental impact, which is manifested in the following aspects: (1) accelerating the exchange rate of the water body of the bay and reducing the content of active phosphate in the bay. Improving the water quality of the bay and enhancing the water power of the bottom of the bay can help to clear the silt at the bottom of the bay. Therefore, the phase difference tide energy is a kind of environment-friendly mode of ocean energy development, which provides a new way for the exploitation of tidal energy resources.
【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：P743.3

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