变转速旋翼气动特性分析及试验研究
收稿日期: 2012-10-23
修回日期: 2013-03-11
网络出版日期: 2013-03-22
基金资助
国家自然科学基金(11202097);航空科学基金(2011ZA52004)
Analysis and Experimental Investigation on the Aerodynamic Characteristics of Variable Speed Rotor
Received date: 2012-10-23
Revised date: 2013-03-11
Online published: 2013-03-22
Supported by
National Natural Science Foundation of China (11202097);Aeronautical Science Foundation of China (2011ZA52004)
直升机旋翼以固定不变的转速工作,仅能使有限状态的旋翼效率达到最优,而通过旋翼转速的变化,可以实现不同飞行状态下的旋翼效率最优。为了研究不同旋翼转速时的旋翼气动特性,首先建立了适合旋翼在低转速飞行情况下的气动特性分析模型,该模型包含了Leishman-Beddoes非定常动态失速模型与适合于低马赫数(Ma<0.3)分析的Sheng失速修正模型;其次,在低速风洞2.5 m旋翼模型试验台上试验研究了模型旋翼的悬停效率及前飞需用功率与旋翼转速之间的关系。试验与计算结果的对比表明:所建立的气动分析模型能够准确地计算旋翼在低转速情况下的气动特性;通过优化旋翼转速,增大了桨叶剖面迎角,提高了桨叶剖面的升阻比;并且当旋翼以最优转速旋转时,模型旋翼的悬停效率最大可以提高32%,前飞需用功率最大可以降低22%。
徐明 , 韩东 , 李建波 . 变转速旋翼气动特性分析及试验研究[J]. 航空学报, 2013 , 34(9) : 2047 -2056 . DOI: 10.7527/S1000-6893.2013.0168
When helicopters work at fixed rotor speeds, optimal rotor efficiency cannot be achieved in all flight states. It can only be realized at different flight states by varying rotor speeds. In order to investigate the aerodynamics of variable speed rotors, an analytical model applying to low speed rotors is first derived. The Leishman-Beddoes unsteady and dynamic stall model and a modified Sheng dynamic stall model for low Mach numbers (Ma<0.3) are introduced. Then, a test in a 2.5 m diameter helicopter rotor model test rig at a low speed wind tunnel is conducted, and the effects of rotor speeds on the figure of merit and the rotor power required are investigated. Finally, the comparisons between the experimental data and calculation demonstrate that the aerodynamic characteristics for low speed rotors can be accurately predicted by the analytical model. By optimizing the rotor speed, the lift to drag ratio of an airfoil can be effectively improved by the increase of the angle of attack. When the rotor is working at the optimal rotor speed, the figure of merit can be improved by 32% and the rotor power can be maximally reduced by 22%.
[1] Steiner J, Gandhi F. An investigation of variable rotor rpm on performance and trim. Proceedings of the American Helicopter Society 64th Annual Forum, 2008. https://vtol.org/store/product/an-investigation-of-variable- rotor-rpm-on-performance-and-trim-3208.cfm.
[2] Chen R T N. An exploratory investigation of the flight dynamics effects of rotor rpm variation and rotor state feedback in hover. NASA Technical Memorandum 103968, 1992: 9-43.
[3] Guo W, Horn J F. Rotor state feedback control for rotorcraft with variable rotor speed. AIAA Guidance, Navigation, and Control Conference, 2009, 5797: 1-12.
[4] Horn J F, Guo W. Flight control design for rotorcraft with variable rotor speed. Proceedings of the American Helicopter Society 64th Annual Forum, 2008. https://etda.libraries.psu.edu/paper/10241/5239.
[5] Guo W, Horn J F. Helicopter flight control with variable rotor speed and torque limiting. Proceedings of the American Helicopter Society 65th Annual Forum,2009. https://vtol.org/store/product/helicopter-flight-control-with- variable-rotor-speed-and-torque-limiting-2423.cfm.
[6] Graham B D, Inderjit C. Aeromechanics of a variable speed rotor. Proceedings of the American Helicopter Society 67th Annual Forum, 2011. https://vtol.org/store/product/aeromechanics-of-a-variablespeed-rotor-5193.cfm.
[7] Anubhav D, Hyeonsoo Y, Thomas R. Experimental investigation and fundamental understanding of a slowed UH-60A rotor at high advance ratios. Proceedings of the American Helicopter Society 67th Annual Forum, 2011. https://vtol.org/store/product/experimental-investigation- and-fundamental-understanding-of-a-slowed-uh60a-rotor-at-high-advance-ratios-5189.cfm.
[8] Ben B, Inderjit C. Wind tunnel testing for performance and vibratory loads of a variable speed mach scale rotor. Proceedings of the American Helicopter Society 67th Annual Forum, 2011. https://vtol.org/store/product/wind-tunnel-testing-for-performance-and-vibratory-loads-of-a-variablespeed-machscale-rotor-5188.cfm.
[9] Abraham E K. Optimum speed rotor: U.S, Patent Application 60/072,98. 1999-02-19. http://www.google.com/patents/US6007298
[10] James D, David F. Operational benefits of an optimal widely variable speed rotor. Proceedings of the American Helicopter Society 66th Annual Forum, 2010. https://vtol.org/store/product/operational-benefits-of-an-optimal-widely-variable-speed-rotor-1697.cfm.
[11] Han D. Study on the performance and trim of helicopters with variable speed rotors. Acta Aeronautica et Astronautica Sinica, 2013, 34(6): 1241-1248.(in Chinese) 韩东. 变转速旋翼直升机性能及配平研究. 航空学报,2013, 34(6): 1241-1248.
[12] Bousman W G. A qualitative examination of dynamic stall from flight test data. Journal of the American Helicopter Society, 1998, 43(4): 279-295.
[13] Wang R, Xia P Q. Control of helicopter rotor blade dynamic stall and hub vibration loads by using multiple trailing edge flaps. Acta Aeronautica et Astronautica Sinica, 2013, 34(6): 1083-1091. (in Chinese) 王荣, 夏品奇. 多片后缘小翼对直升机旋翼桨叶动态失速及桨毂振动载荷的控制. 航空学报,2013, 34(6): 1083-1091.
[14] Leishman J G, Beddoes T S. A semi-empirical model for dynamic stall. Journal of the American Helicopter Society, 1989, 34(3): 3-17.
[15] Leishman J G. Validation of approximate indicial aerodynamic functions for two dimensional subsonic flow. Journal of Aircraft, 1988, 25(10): 914-922.
[16] Sheng W, Galbraith R A M, Coton F N. A modified dynamic stall model for low Mach mumbers. Journal of Solar Energy Engineering, 2008, 130(3): 1-10.
[17] Sheng W, Galbraith R A M, Coton F N. A new stall-onset criterion for low speed dynamic stall.Journal of Solar Energy Engineering, 2008, 130(3): 461-471.
[18] Sheng W, Galbraith R A M, Coton F N. On the return from aerofoil stall during ramp-down pitching motions. Journal of Aircraft, 2007, 44(8): 1856-1864.
[19] Shao S, Zhu Q H, Zhang C L, et al. Prediction of airfoil airload at low Mach numbers based on state space formulation. Journal of Aerospace Power, 2012, 27(1): 137-144.(in Chinese) 邵松, 朱清华, 张呈林, 等. 基于状态空间法的低马赫数翼型气动载荷计算. 航空动力学报,2012, 27(1): 137-144.
[20] Niven A J, Galbraith R A M. Modeling dynamic stall vortex inception at low Mach number. Aeronautic Journal, 1997, 101(1002): 67-76.
[21] Ericsson L E. Dynamic airfoil flow separation and reattachment. Journal of Aircraft, 1995, 32(6): 1191-1197.
/
| 〈 |
|
〉 |
CJA