Airfoil transition and separation studies using an infrared imaging system
Airfoil transition and separation studies using an infrared imaging system
复制标题
使用红外成像系统进行翼型转变和分离研究
DOI：
10.2514/3.46016
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发表时间：
1991
影响因子：
2.2
通讯作者：
A. S. Roberts
中科院分区：
文献类型：
--
作者：
E. Gartenberg;A. S. Roberts
红外成像系统用于检测 NACA 0012 机翼上从零攻角到分离的边界层流态的热特征。在翼型热分析图上可以看到边界层从层流到湍流的转变以及分离的开始。将这些发现与视觉和红外成像系统可观察到的铝箔簇的行为进行了比较。这种布置提供了使用红外成像系统通过表面热成像仪进行流态检测和通过铝箔簇进行流态可视化的选项。最终，由于升力面攻角的变化而导致的表面温度变化提供了解释边界层流态的方法。命名法 Cf>x = 局部表面摩擦系数 hx = 局部传热系数 k - 空气导热系数 Nux = 局部努塞尔数 Pr = 空气普朗特数 Rex = 局部雷诺数 Stx = 局部斯坦顿数 s = 翼型上表面弧长 U = 自由流空气速度 u = 边界层流向速度分量 x = 弦向坐标 y - 垂直于翼型表面的方向 a = 攻角 v = 空气运动粘度
An infrared imaging system was used to detect the thermal signature of boundary-laye r flow regimes on a NACA 0012 airfoil from zero angle of attack up to separation. The boundary-layer transition from laminar to turbulent flow and the onset of separation could be seen on the airfoil thermograms. The findings were compared against the behavior of aluminum foil tufts observable both visually and with the infrared imaging system. This arrangement offers the option of using the infrared imaging system both for flow regime detection through surface thermograph} and flow visualization by the aluminum foil tufts. Ultimately the surface temperature changes due to variation in the angle of attack of a lifting surface provide a means for interpretation of the boundary-layer flow regimes. Nomenclature Cf>x = local skin-friction coefficient hx = local heat transfer coefficient k - air thermal conductivity Nux = local Nusselt number Pr = air Prandtl number Rex = local Reynolds number Stx = local Stanton number s = airfoil upper surface arc length U = freestream air velocity u = boundary-layer streamwise velocity component x = chordwise coordinate y - direction perpendicular to the airfoil surface a = angle of attack v = air kinematic viscosity