Application exploration of Tomo-PIV in the subsonic and transonic wind tunnel
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摘要: 层析粒子图像测速技术(Tomographic Particle Image Velocimetry,Tomo-PIV)是将PIV技术和计算机断层诊断技术(CT)相结合的一种瞬时三维流场速度测量技术,能够定量获取流场的三维结构。通过对该技术的研究,实现了其在亚跨超声速风洞的应用,并进行了超临界翼型小肋减阻的试验验证。基于中国航天空气动力技术研究院FD-12亚跨超声速风洞,设计了体光源和相机等硬件设备的布局方案,解决了示踪粒子的均匀播撒问题,测量了Ma=0.6条件下的自由来流流场,并与PIV测试结果进行对比,两者数据吻合较好,验证了Tomo-PIV的测量精度。针对超临界翼型OAT15a,测量了翼型表面分别贴附光滑薄膜和顺流向对称V形小肋薄膜后翼型尾缘后方的三维速度场。对比发现,贴附小肋薄膜后尾缘后方流场的马赫数增大,说明小肋能够减小翼面摩擦阻力,具有一定的减阻效果。Abstract: Tomographic Particle Image Velocimetry(Tomo-PIV) is a kind of instantaneous velocity measurement technology combined PIV and computer tomography (CT), which can quantitatively obtain the three-dimensional structure of the flow field. It is successfully applied in the subsonic, transonic and supersonic wind tunnel and the supercritical airfoil verification experiment about riblets drag reduction was carried out. The layout of body light and camera is designed based on the situation of FD-12 wind tunnel in China Academy of Aerospace Aerodynamics. The free flow field under the condition of Ma=0.6 is measured by solving the problem of the uniformity diffusion of tracer particle, and compared with the test results of PIV. The data of both accord well, verifying the accuracy of Tomo-PIV. Meanwhile, the three dimensional velocity field in the rear of trailing edge is measured by attaching the smooth film and symmetrical riblets film respectively which used supercritical airfoil OAT15a as the carrier. The results reveal that the Mach number of the measurement field increases after attaching the riblets film. It shows that the riblets film can reduce the friction resistance of the wing and has certain drag reduction effect.
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Key words:
- Tomo-PIV /
- subsonic and transonic wind tunnel /
- riblets film /
- drag reduction /
- supercritical airfoil
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表 1 不同来流马赫数下对应的小肋无量纲尺寸
Table 1. Dimensionless scale of riblets corresponding to different inflow parameters
来流马赫数 Ma=0.6 Ma=0.7 无量纲高度 10.587 12.993 无量纲宽度 11.931 14.642 表 2 Tomo-PIV计算参数
Table 2. Calculation parameters of Tomo-PIV
参数 数值 相机跨帧时间 700 ns 相机分辨率 2456 pixel×2058 pixel 空间分辨率 35.1 pixel/mm 景深和光圈 32 mm/8 重构区域大小 45 mm×30 mm×12 mm 互相关迭代窗口 64 voxel×64 voxel×64 voxel 窗口重叠因子 75% 表 3 小肋减阻效果
Table 3. The drag-reduction effect of riblets film
来流马赫数 小肋膜后平均马赫数 光膜后平均马赫数 减阻效果 Ma=0.6 0.5697 0.5663 0.6% Ma=0.7 0.6543 0.6451 1.4% -
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