Development of a high-performance wind turbine system by concentrating wind energy

为了促进风能的利用，我们开发了一种新型的风力发电系统。风力机系统由风力机、出口边缘为环形边缘的扩散器护罩和进口护罩组成。我们称其为带边缘扩散器的带冠风力涡轮机。加边扩散器可以通过捕获和集中周围的风来加速接近的风进入风力涡轮机。也就是说，由于边缘分离流产生的负压，风被引入扩散器。环形板(边缘)在下游产生大涡，进一步增加扩散器入口处的流动加速度。为了提高复盖式风力机的性能，我们研究了有缘扩散器、进口盖板和风力机本身的优化设计。因此，最新型号的带冠风力涡轮机在给定涡轮机直径和风速的情况下，与裸风涡轮机相比，功率增加了约5倍。此外，裹尸式风力机还有其他几个重要的特点。最重要的特点是防止叶片断裂的安全性和通过扩散器降低叶片尖端噪声。我们还开发了一种用于风系统预报的数值绳索，称为RIAM-COMPACT。使用这根绳子，我们可以分析复杂地形上的风流。该方法是基于大涡模拟的湍流模型，可以对非定常湍流风场进行高精度的数值模拟。

In order to promote the utilization of wind energy, we have developed a new type wind turbine system. The wind turbine system consists of a wind turbine, a diffuser shroud with a ring-shaped brim at the exit periphery and an inlet shroud. We call it as a shrouded wind turbine with a brimmed- diffuser. The brimmed diffuser can accelerate the approaching wind into the wind turbine by capturing and concentrating the surrounding wind. Namely, the wind is induced into the diffuser because of the negative pressure caused by the separation flow from the brim. The ring-shaped plate (brim) generates large eddies downstream which further increases the flow acceleration at the diffuser entrance. To increase the performance of the shrouded wind turbine, we have investigated the optimum design of the brimmed diffuser, inlet shroud and wind turbine itself. As a result, the latest model of shrouded wind turbine has demonstrated power augmentation for a given turbine diameter and wind speed by a factor of about 5 compared with a bare wind turbine. Moreover, the shroud wind turbine has other several important features. Most important features are the safety against the broken blades and the reduction of the blade tip noise by the diffuser.We have also developed a numerical cord for wind system prediction called ‘RIAM-COMPACT'. Using this cord, we can analyze the wind flow over a complex terrain. This cord is based on Large Eddy Simulation as a turbulence model and can provide a flow simulation of an unsteady and turbulent wind field with high accuracy.