Unsteady flow interaction mechanism of coaxial rigid rotors in hover

被引：0
|
作者：
Zhu Z. [1 ]
Zhao Q. [1 ]
Li P. [1 ]
机构：
[1] National Key Laboratory of Science and Technology on Rotorcraft Aeromechanics, Nanjing University of Aeronautics and Astronautics, Nanjing
来源：
Hangkong Xuebao/Acta Aeronautica et Astronautica Sinica | 2016年 / 37卷 / 02期
基金：
中国国家自然科学基金;
关键词：
Blade-tip vortex; Coaxial rigid rotor; Computational fluid dynamics; Hovering condition; Interaction mechanism; Moving-embedded grid; Unsteady flow field;
D O I：
10.7527/S1000-6893.2015.0106
中图分类号：
学科分类号：
摘要：
A computational fluid dynamics (CFD) method based on moving-embedded grid technique is established to simulate the unsteady flow field of the coaxial rigid rotor in hover. In this solver, based on the highly-efficient moving-embedded grid technology, the simulation method is developed by solving the compressible Reynolds-averaged Navier-Stokes (RANS) equations with Baldwin-Lomax turbulence model and a dual-time method. Based upon the validation of the present CFD method, during the process of blade-vortex interaction in hover, close vortex-surface interactions and impingement phenomenon have been observed; at the same time, the interaction process among the vortexes shed from the upper blades and lower blades has been captured obviously, as a result, the evolution laws of position and strength of blade-tip vortex shed from different blades are obtained in detail. Furthermore, the periodic unsteady characteristics and variation trend of the aerodynamic forces of the upper rotor and lower rotor have been analyzed. The simulation results demonstrate that the upper blade vortices can impinge upon the lower blade, which causes the thrust loss of lower blade; the strength and positions of the vortexes shed from upper blades and lower blades could change due to the interaction; the forces on both the upper and lower rotors increase as the blades approach, then decrease and increase again as they move away. © 2016, Press of Chinese Journal of Aeronautics. All right reserved.
引用
收藏
页码：567 / 578
页数：11
相关论文
共 24 条
  • [1] Leishman J.G., Syal M., Figure of merit definition for coaxial rotors, Journal of the American Helicopter Society, 53, 3, pp. 290-300, (2008)
  • [2] Leishman J.G., Ananthan S., An optimum coaxial rotor system for axial flight, Journal of the American Helicopter Society, 53, 4, pp. 366-381, (2008)
  • [3] Leishman J.G., Aerodynamic performance considerations in the design of a coaxial proprotor, Journal of the American Helicopter Society, 54, 1, (2009)
  • [4] Leishman J.G., Ananthan S., Aerodynamic optimization of a coaxial proprotor, Proceedings of the 62th Annual Forum of the American Helicopter Society, pp. 64-85, (2006)
  • [5] Andrew M.J., Coaxial rotor aerodynamics in hover, Vertica, 5, 2, pp. 163-172, (1981)
  • [6] Bagai A., Leishman J.G., Free-wake analysis of tandem, tilt-rotor and coaxial rotor configurations, Journal of the American Helicopter Society, 41, 3, pp. 196-207, (1996)
  • [7] Huang S.L., Xu G.H., Li C.H., Flow field analysis of coaxial twin rotor based on free wake, Journal of Nanjing University of Aeronautics and Astronautics, 40, 6, pp. 721-726, (2009)
  • [8] Kim H.W., Brown R.E., A rational approach to comparing the performance of coaxial and conventional rotors, Journal of the American Helicopter Society, 55, 1, (2010)
  • [9] Kim H.W., Brown R.E., A comparison of coaxial and conventional rotor performance, Journal of the American Helicopter Society, 55, 1, (2010)
  • [10] Tong Z.L., Sun M., Navier-Stokes calculations of coaxial rotor aerodynamics, Acta Aeronautica et Astronautica Sinica, 19, 1, pp. 1-5, (1998)
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