风机翼型边界层分离的二维数值模拟研究.doc

毕业设计(论文)
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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变会使流体运动速度的大小和方向发生改变,从而产生流动分离。流动分离产生的冲击会造成流动损失。流体运动速度的大小和方向的改变,也会使得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,使气体在风机叶片的吸力面上形成旋涡,造成边界层分离现象而会导致能量损失。针对G4-73风机翼型,利用商业软件FLUENT的前期处理工具Gambit建立二维不可压缩湍流模型,再利用FLUENT对翼型在-36°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 flow separation will cause the flow 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 shock loss will affect the efficiency and performance of the gas with impact speed imported into the entrance of impeller, it will bring about the vortex on the suction is the reason leading to boundary layer the help of Gambit,a processing tool of FLUENT software,a pressible 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°. pare 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
研究背景及意义 1
国内外研究现状和趋势 2
研究方法及主要内容 3
2 翼型基本知识 4
几何参数 4
气动特性 5
影响气动特性的主要因素 6
3 数值模拟理论 8
边界条