-
The present paper contributes to the modeling of unsteady aerodynamics of Vertical Axis Wind Turbines (VAWT). A Double Multiple Stream Tube (DMST) model as an engineering approach for design and optimization of VAWT is presented. The unsteady flow around a H-type rotor is investigated numerically in two and three dimensions using Computational Fluid Dynamics (CFD).6881
- 上一篇：轧钢机英文文献和中文翻译
- 下一篇：钢筋混凝土桥梁英文文献和中文翻译
本文论述直立式风力发电机不稳定风力动力学模型，垂直风力发电机的双多留管模型的设计和优化方法，二文和三文H型转子的绕流数值研究。
1 Introduction
介绍
In recent years an increasing demand in decentralized power plants is observedrenewing the interest in Vertical AxisWind Turbines (VAWT). Compared to HorizontalAxis Wind Turbines (HAWT), VAWT presents several advantages such as lower soundemission, its insensitivity to yaw and wind direction and its increased power outputin skewed flow. Due to their simpler configuration, the production costs and serviceeffort are potentially lower than for HAWT. These observations also have driven thepromotion of small scale VAWT for the residential environment. In some sense, theprice paid for structural simplicity is aerodynamic complexity; VAWT aerodynamics isinherently unsteady and beyond the limits of classical airfoil theory. However, recentdevelopments in computational methods and the capability of predicting in detail theunsteady flow in such rotating machinery greatly increase the understanding of VAWTaerodynamics.
近年来对分散式发电厂的需求增加，在直立式发电机的利益不断扩大。与水平式风力发电机相比直立式具有降低噪音、偏航和风向的不敏感性和降低倾泄流的输出功率。由于其结构简单，其生产成本及服务低于水平式风力发电机。这些优点促进了小规模直立式风力发电机应用于居住环境，在某种意义上结构简单付出的代价是空气动力学的复杂性，直立式风力发电机空气动力学固有的不稳定超越了经典翼理论的极限。然而，最近计算方法和对非定常流动旋转机械详细预测能力的发展极大的增加了对直立式风力发电机的了解。
The object of investigation is the so called H-rotor, consisting of two straight NACA-4418 airfoils which are connected with the shaft at both ends, as shown in Figure 1a.From Figure 1b it is obvious that during one rotor revolution, the relative velocity at the airfoil W as well as the angle of attack α is changing significantly. The blades are then operated in a stalled condition most of the time.
研究的对象是H转子，它是由连接在轴两端的两条NACA-4418组成如在图1a中所示，从1b中很明显看出其相对速度以a角改变，叶片大部分处于失速状态。
For the design and analysis of Darrieus wind turbines, the Double Multiple StreamTube (DMST) model was found to be very efficient [3]. The DMST model instantly delivers global parameters of the turbine, such as the power coefficient of the turbine and blade loads, all depending on geometrical details of the configuration or operating conditions. It is based on simplified one-dimensional aerodynamic consideration and with the model from Gormont [1] includes the dynamic stall effects. Although validated for the Darrieus wind turbine, the DMST model with the Gormont model does not givesatisfying results for the existing H-Rotor design. The reason for that is the fact that the implemented dynamic stall model is based on empirical observations which are valid only for a certain class of airfoils, i.e. slender, symmetric profiles. The presented results are a step towards the development of models to include dynamic stall effects of particular airfoil types as well as the effect of finite airfoil span and the rotor traverse parts into the DMST model.
对于达里厄风发电机的设计和分析，双多流管模型非常有用。DMST模型立即传送发电机的全部参数，如发电机的功率系数和叶片的负荷。所有这些取决于几何关系及工作条件。它基于简化的一文空气动力学的考虑。尽管达里厄风力发电机得以验证，具有Gormont模型的DMST模型不能给现有H转子设计的满意结果。其中的原因是一个事实是实施动态失速模型是基于经验观察仅适用于某一类的翼型，即修长，对称的配置文件。所提出的结果是一步包括动态失速的影响特别是翼型件的类型以及效果有限翼型跨度和转子的横动到DMST模型的发展。