水平轴潮流能水轮机空化特性研究

Study on cavitation characteristics of horizontal axis tidal turbine

采用CFD(计算流体力学)数值模拟的方法,对水平轴潮流能水轮机的空化特性进行研究.重点讨论叶片空化的特性和对水轮机水动力性能的影响,得出不同空化数下叶片空化程度和位置及对水动力性能的损耗.在相同空化数下,分别研究来流速度及叶轮旋转角速度对叶片空化情况的影响,得出不同工况下叶片的空化区域,针对空化区域的不同研究水动力性能的降低程度.结果表明:叶片的空化程度及区域不仅和空化数有关,还受到叶尖速比的影响;空化的发生并不一定会严重影响水轮机的水动力性能,空化对水动力性能的影响关键在于空化发生的区域,只有当空化数低于一定数值,叶片中段发生空化时,才会大幅影响水动力性能.

The cavitation characteristics of horizontal axis tidal turbine was studied by using CFD （computational fluid dynamics）numerical simulation method. The cavitation characteristics of blade and the effect of hydrodynamic performance were focused on, the extent and location of cavitation on the blade in different cavitation number, and the loss of the hydrodynamic performance was obtained meanwhile. At the same cavitation number, the impact of the flow velocity and the angular velocity of rotation were studied, the region of cavitation on the blade in different situation was obtained, and then the reduction of hydrodynamic performances of the turbine were studied at the different region of cavitation. The results show that the extent and region of cavitation is not only associated with the cavitation number, but also affected by the tip speed ratio; the occurrence of cavitation will not neces- sarily affect the hydrodynamic performance of the turbine, the key of the influence of the cavitation on the hydrodynamic performance is the area of cavitation, which would greatly affect on the hydrody- namic performance only when the cavitation number is lower than a certain value and the cavitation occurs in the middle part of blade.