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涡轮机系统。风力涡轮机系统由风力涡轮机、在出口周边具有环形边缘的扩散器护罩和入口护罩组成。我们称之为带边缘扩散器的带罩风力涡轮机。带边缘的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，由于来自边缘的分离流引起的负压，风被引入扩散器。环形板（边缘）在下游产生大的涡流，这进一步增加了扩压器入口处的流动加速度。为了提高闭式风力涡轮机的性能，本文对带缘扩压器、进气道罩和涡轮机进行了优化设计。因此，最新的带罩风力涡轮机模型已经证明，与裸风力涡轮机相比，对于给定的涡轮机直径和风速，功率增加约5倍。此外，护罩风力涡轮机具有其它几个重要特征。最重要的特点是防止叶片断裂的安全性和通过扩压器降低叶尖噪音。我们还开发了一种用于风系统预测的数值线，称为“RIAM-COMPACT”。使用这根线，我们可以分析复杂地形上的风流。该cord基于大涡模拟作为湍流模型，可以提供高精度的非定常湍流风场的流动模拟。

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.