PIV measurements in the wake of coaxial-rotor in water tunnel
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摘要: 采用粒子图像测速(PIV)技术,对共轴式双旋翼在悬停和以不同前进比前飞时的流场进行水洞实验.将激光片光定位于旋翼的纵向截面,桨叶的方位角和图像的获取是同步的.测量得到了旋翼流场的瞬时涡量和速度分布、桨尖涡的结构和脱落轨迹、悬停时的尾迹边界收缩和前飞时的尾迹边界倾斜角等.研究了不同状态下共轴式双旋翼流场的气动干扰特性.为了比较,对单旋翼也进行了同样的测量.实验得到了有价值的结果,对共轴式直升机的气动计算和合理设计具有重要意义.Abstract: Particle image velocimetry (PIV) technique was applied to the experiment of coaxial-rotor in hover and in forward flight in water tunnel. The laser sheet was positioned for tip vortices shed at zero and 180 degrees azimuths. The rotor rotation and the imaging system were synchronized to acquire PIV images at specified rotor azimuth angles. Instantaneous vorticity and velocity distributions of the rotor flow fields were obtained. The tip vortices were tracked from their generation to convection downstream. The wake contractions in hover and the wake boundary inclination angles in forward flight were measured. The wake geometries and aerodynamic interaction characteristics of coaxial-rotor flow fields were investigated. For comparison, single-rotor flow fields were also measured. The agreement of the experimental results with the literatures indicates PIV is effective to investigate complex flow fields in water tunnel. The valuable results have important meanings to the aerodynamic calculation and reasonable design of coaxial-rotor helicopter.
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Key words:
- coaxial helicopter /
- rotor flow fields /
- wake /
- water tunnel experiment /
- particle image velocimetry
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[1] Akimov A I, Butov V P, Bourtsev B N, et al. Flight investigation of coaxial rotor tip vortex structure 50th Annual Forum of the American Helicopter Society. USD:Washington D C, 1994 [2] 李洪昌.共轴式双旋翼尾迹形态及桨尖涡结构的实验研究 .北京:北京航空航天大学航空科学与工程学院,2004 Li Hongchang. Experimental inves tigation of coaxial rotor wake and tip vortex . School of Aeronautic Science and Engineering, Beijing University of Aeronautics and Astronautics, Beijing, 2004(in Chinese) [3] 高正.直升机空气动力学的新成果[M].北京:航空工业出版社,1999 Gao Zheng. Recent achievements in the field of helicopter aerodynamics[M]. Beijing:Aviation Industry Press, 1999(in Chinese) [4] 邓彦敏,陶然,胡继忠.共轴式直升机上下旋翼之间气动干扰的风洞实验研究[J].航空学报,2003,24(1):10-14 Deng Yanmin, Tao Ran, Hu Jizhong. Experimental investigation of the aerodynamic interaction between upper and lower rotors of a coaxial helicopter[J]. Acta Aeronautica et Astronautica Sinica, 2003, 24(1):10-14(in Chinese) [5] Mahalingam R, Komerath N M. Measurements of the near wake of a rotor in forward flight . AIAA-98-0692, 1998
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