新型垂直轴潮流能水轮机——潜式载体系统研究

Converting the hydrokinetic energy of tidal current into electricity power is an improtant way of harnessing marine energy. There are two classes of tidal turbine commonly used: the horizontal axis turbine (or called axial-flow turbine) and the vertical axis turbine. Though vertical axis turbine is a bit less efficient than horizontal axis turbine, it is adapted to the variation of current direction thus eleminates the requirement of rotor yawing system and leads to structural simplicity and high reliability in running. The vertical axis turbine, especially that with straight balde, is simple in shape so that the manufaturing cost is low. Low manufaturing cost and high relability is the most favorable features of vertical axis turbine. Usually a tidal current turbine is either installed on a structure mounting on the seabed, a pile foundation or hung under a moored vessel floating on the sea surface. The seabed mounting structure and pile foundation are stable but expensive in building and mounting. If the water depth grows up to dozens of meters, the cost of seabed mounting or pile foundation system is unaffordable. The floating carrier is cheaper, but is unstable in windy and wavy climate and facing the risk of demaging in sever storm condition that will cause huge lost. In this project, a vertical axis turnine will be installed on a submerged carrier which is moored by chains and floating below sea surface and above seabed. In this way the turbine system can avoid the affection of wind and wave, and take the advantage of low manufaturing and deploying cost. The hydrodynamic performance of the submerged turbine-carrier system are investigated by flume model tests and three-dimensional numerical simulation, the knowleadge gained will be used to guide the design of a full-scale device.

利用潮流的动能发电是海洋能利用的一种重要形式。目前常见的潮流能水轮机，有水平轴贯流式和垂直轴式两种。垂直轴水轮机的能量转换效率虽然比水平轴水轮机稍低，但可适应潮流方向的变化，不需要迎流控制装置，结构简单，可靠性高。垂直轴水轮机，尤其是直叶片垂直轴水轮机，形状简单，制造成本低。低成本和高可靠性是垂直轴水轮机最大的优点。现有的潮流能水轮机通常安装在坐底式、桩柱式基础或悬吊在浮式载体上。坐底式和桩柱式基础较稳定，但制造、安装成本高昂，在水深达到数十米以上时，其成本难以承受。浮式载体造价低，但受风浪影响大，不稳定，在大风浪中易损坏，造成较大损失。本项目提出把垂直轴式水轮机安装在潜式载体上，用锚链系留，漂浮于海面和海床之间，即可避开海面风浪的影响，又造价低廉。本项目将利用物理模型实验和三维数值模拟手段，对这种潜式垂直轴潮流能水轮机系统的水动力特性进行研究，为以后全尺寸样机的设计提供依据。

本基金项目采用数值模拟和水槽模型实验手段，对垂直轴潮流能水轮机及其潜式载体的水动力性能进行了系统的研究。研究内容包括水轮机几何参数优化、导流涵道与水轮机相互影响、叶片变偏角策略及其对水轮机性能的影响、新型叶片的水动力特性研究、潜式载体动力响应特性、叶片和旋臂结构优化等等。研究证明了垂直轴潮流能水轮机具有结构简单可靠、潮流能效率高的特点，其性能可以通过采用变偏角叶片、结合导流涵道、采用高性能的新型叶片等措施得到进一步提升。本项目的研究成果对于潮流能开发技术的推广应用具有重要的科学和实际工程意义。