李维敬-200604000513-热能与动力工程专业0601班-大论文.doc

风机翼型边界层分离的二维数值模拟研究 摘要 当风机工作时，气体流道的几何形状改流体运动速度的大小和方向发生改变产生产生的冲击会造成流动损失。流体运动速度的大小和方向改变使气体在进入叶片入口和从叶轮出来进入压出室时，流动角不等于叶片的安装角，从而产生冲击损失影响风机的效率和性能由于气体进入叶片入口时存在着冲击速度，使气体在上形成旋涡，造成边界层分离现象而导致能量损失°到8°的空气来流攻角下的气动特性进行了相应的数值模拟计算，然后，对不同攻角下模拟所得到的速度矢量图进行比较分析，得出风机翼型边界层分离和攻角的关系。 关键词：风机翼型；边界层；数值模拟；攻角 THE 2D NUMERICAL SIMULATION OF THE BOUNDARY LAYER SEPARATION ON A WIND TURBINE AIRFOIL Abstract When the fan working, the gas flow channel geometry will change，which makes the fluid velocity magnitude and direction change resulting flow separation.The flow separation will cause the flow loss.The change of the fluid velocity magnitude and direction makes the flow angle be not equal to the installation angle when the gas is going into the impeller from the entrance and out from the impeller,resulting in shock loss.The shock loss will affect the efficiency and performance of fans.When the gas with impact speed imported into the entrance of impeller, it will bring about the vortex on the suction side.This is the reason leading to boundary layer separation.With the help of Gambit，a processing tool of FLUENT software，incompressible turbulence model of a kind of wind turbine airfoil was built. Of course，the specific airfoil of this study is G4-73. Under the different Angle of Attack，the aerodynamic performance of 2D aerofoil of wind turbine airfoil was simulated and analyzed by using the FLUENT software. The AoA of this study was changed from -36° to 8°. Then compare the speed vector diagrams obtained via the FLUENT software and find out the relation between the boundary layer separation on the wind turbine airfoil and the Angle of Attack. Keywords: Wind turbine airfoil; Boundary layer separation; Numerical simulation; Angle of Attack 目录 摘要 I Abstract II 1 绪论 1 1.1 研究背景及意义 1 1.2 国内外研究现状和趋势 2 1.3 研究方法及主要内容 3 2 翼型基本知识 4 2.1 几何参数 4 2.2 气动特性 5 2.3 影响气动特性的主要因素 6 3 数值模拟理论 8 3.1 边界条件的确定 8 3.2 k-ε模型 8 4 数值模拟结果及分析 10 4.1 利用GAMBIT建立计算模型 10 4.2 利用FLUENT进行模拟计算 11 4.3 模拟结果分析 15 4.3.1 对攻角为-36°时的模拟结果分