A Development of Operating System with Darrieus-type Cross-flow Water Turbine for Ultra-low Head Hydro-power

达里厄斯型横流水轮机是为超低水头水轮机而开发的，其外形和结构简单，可降低投资和维护成本。为阐明高效转轮设计和优化控制的指导原则，对矩形管道内直叶片Darrieus型转轮进行了模型试验。这些系统的工作成果如下。1)推荐的转轮叶片参数为：NACA0015-0018型叶片断面较佳，叶片弦长与转轮螺距圆半径之比L/R=0.3左右，叶片安装角与螺距圆相切。2)三叶转轮效率高与扭矩时变小之间的折衷。3)提出了将叶片支承到转轴上的方法，以减少转轮的摩擦损失，而不会因叶尖效应而影响叶片的性能。4)通过实验和数值模拟，评价了该型水轮机带发电机和提速装置到任意工作点的自启动和运动过程的特点。5)提出了一种对水轮机系统进行有效控制的简单方法。6)给出了优化流道的水力性能曲线和空化极限曲线，为设计推荐的最佳效率流道提供了有用的数据。7)提出了使转轮性能最优、水力损失最小的进水口、转轮壳体和尾水管壁型优化的指导原则。最后，通过与其他常规水轮机的比较，说明了达里乌斯型水轮机在扬程、流量和可用输出功率方面的适用范围。

The Darrieus-type cross flow water turbine has been developed for ultra low head hydro power from the reason that its simple shape and structure could reduce the capital and maintenance costs. Model tests of the Darrieus-type runner with straight blades in a rectangular ducted casing have been conducted with theoretical consideration to clarify the guiding principles for designing high efficiency runner and operating under optimum control. Results of those systematic works are as follows. 1)Runner blade parameters as the preferable blade sectional profile of NACA0015-0018, the ratio of blade chord length to the radius of pitch circle of the runner of l/R=about0.3, the blade setting angle tangent to the pitch circle are recommended. 2)The compromise between high efficiency and small time variation of torque yeilded three bladed runner. 3)The method to support the blades to the rotating shaft was proposed t o reduce a friction loss of the runner without dete-riorating the blade performance due to a blade tip effect. 4)The characteristics of the self-starting and moving processes of this type of water turbine with a generator and a speed in creasing device to any operating point were evaluated by experiments and a numerical simulation. 5)A simple method to control the system of this type of water turbune effectively was proposed. 6)The curves of hydro performance and cavitation limit of a runner with the optimum configuration were shown as useful data for designing the recommended best efficiency runner. 7)The guiding principles of the optimum wall shapes of the intake, the runner casing and the draft tube were proposed to make the runner performance maximum and all hydraulic losses minimum. And finally 8)the usable range of the Darrieus-type water turbines was illustrated for head and flow capacity with the available output power in comparison with those of other conventional type of water turbines.