二阶斯托克斯非线性潮波对潮汐贯流式水轮机性能的影响  

Effect of second-order Stokes nonlinear tidal wave on performance of tidal tubular turbines

作　　者：冯建军[1] 朱国俊[1] 王准 吴广宽[1] 罗兴锜[1] Feng Jianjun;Zhu Guojun;Wang Zhun;Wu Guangkuan;Luo Xingqi(Institute of Water Resources and Hydro-electric Engineering,Xi’an University of Technology,Xi’an 710048,China)

机构地区：[1]西安理工大学水利水电学院,西安710048

出　　处：《农业工程学报》2019年第2期48-54,共7页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金项目(51339005;51679195;51479167);陕西省自然科学基础研究计划资助项目(2018JM5102)

摘　　要：双向贯流式水轮机在潮汐能开发中的应用广泛。在海洋波流条件影响下,潮汐能机组在反向运行过程中的水动力性能变化是潮汐能机组研发过程中需要考虑的重要问题。该文采用二阶斯托克斯非线性潮波对海洋潮波来流进行了模拟,建立了二阶斯托克斯非线性潮波边界下的潮汐贯流式水轮机性能分析模型并验证了模型的可靠性。以该模型为基础,采用CFD方法,对某一潮汐贯流式水轮机在反向运行时的内部流动进行数值仿真,重点研究了动态波流边界对贯流式水轮机反向运行时水力特性的影响。研究结果表明:1)考虑波流耦合作用时,潮波与坝体发生碰撞后损失了大部的动能,形成的反射波流,覆盖下一个波峰前的气体形成大气泡进入海洋内部;2)来流潮波与坝体壁面反射潮波的相互作用是形成潮汐贯流式水轮机取水口处夹气涡的原因,形成的夹气涡在液面下旋转前进流入内流场黏附于流道上侧,压缩流场过流面积,形成了一个低压低速的夹气涡流动带,从而改变内流场流动分布和贯流机组的特性;3)动态波流的作用使得潮汐贯流式水轮机转轮叶片上的受力呈现较大幅度波动,叶片受力的低频幅值会随着夹气涡的发展而逐渐增大。同时,在波流影响下机组出力的波动幅度达到3.86%,远高于无波流作用下的不足1%,从而导致电能质量下降。As a form of ocean energy,tidal energy is extremely abundant in oceans,with the characteristics of being clean,reliable,predictable and renewable.In the development of tidal energy,a bi-directional tubular turbine has been widely adopted for power generation.The tubular turbine converts the energy extracted from tides into mechanical energy,and further into useful electricity.The tubular turbine has been well designed suitable for generating power from both flow directions,in order to take full use of the tidal energy not only in the flood tide state but also during the ebb tide state.However,the operation condition of the tubular turbine will be definitely affected by the movement of the wave caused by tide,especially for the reverse power generation direction in which the flow direction is from the ocean to the turbine installed in the hydraulic dam.In this case,under the influence of ocean wave current conditions,the change of hydrodynamic performance during the reverse operation of tidal energy units is an important issue to be considered during the development of tidal energy units.In this paper,the nonlinear second-order Stokes wave law was used to simulate the ocean tide flow,and the second-order Stokes wave formula ocean wave flow condition model has been established based on actual oceanic flow conditions.The chosen tubular turbine had 4 runner blades,with a hub ratio of 0.38 and a runner diameter of 2.5 m.The turbine consisted of an intake part with body,guide vanes,runner and straight draft tube.In order to discrete the computational domains,the grid generation tool ICEM CFD was used to generate high quality structure grids.The number of grids chosen for simulations was approximately 6.5 million,after a grid-independent study with the hydraulic efficiency of the turbine being the examined criterion.The RNG k-ε.turbulence model was chosen to close the time-averaged N-S equations.Transient simulations with considering the effect of the ocean wave on the flow have been realized with the help of ANSYS CFX

关 键 词：水轮机 模型 计算机模拟 波流耦合作用 水力性能 夹气涡 

分 类 号：TK733.8[交通运输工程—轮机工程]