Aerodynamic characteristics of rigid coaxial rotor by wind tunnel test and numerical calculation
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摘要
Focusing on aerodynamic characteristics of rigid coaxial rotor of a high-speed helicopter in hover and forward flight, a wind tunnel test is conducted in the 8 m ? 6 m low-speed straightflow wind tunnel of China Aerodynamics Research and Development Center. In the experiment,a 4 m diameter composite model rigid coaxial rotor is designed and manufactured, and firstorder flapping frequency ratio of the blade is 1.796 to ensure sufficient stiffness at the blade root.Rotor aerodynamic performance is measured under hovering and high advance ratio conditions.Also, the numerical method is used to calculate aerodynamic characteristics in typical states of the rigid coaxial rotor for analysis purpose. The rotor lift-drag ratio and lateral lift offset in the experiment are emphatically analyzed for the rigid coaxial rotor. The results indicate that in forward flight condition, the rotor lift-drag ratio first increases and then decreases with the increment of advance ratio and lift offset. When advance ratio remains constant, with the increment of lift offset, the lift-drag ratio of rigid coaxial rotor first increases and then decreases.
Focusing on aerodynamic characteristics of rigid coaxial rotor of a high-speed helicopter in hover and forward flight, a wind tunnel test is conducted in the 8 m ? 6 m low-speed straightflow wind tunnel of China Aerodynamics Research and Development Center. In the experiment,a 4 m diameter composite model rigid coaxial rotor is designed and manufactured, and firstorder flapping frequency ratio of the blade is 1.796 to ensure sufficient stiffness at the blade root.Rotor aerodynamic performance is measured under hovering and high advance ratio conditions.Also, the numerical method is used to calculate aerodynamic characteristics in typical states of the rigid coaxial rotor for analysis purpose. The rotor lift-drag ratio and lateral lift offset in the experiment are emphatically analyzed for the rigid coaxial rotor. The results indicate that in forward flight condition, the rotor lift-drag ratio first increases and then decreases with the increment of advance ratio and lift offset. When advance ratio remains constant, with the increment of lift offset, the lift-drag ratio of rigid coaxial rotor first increases and then decreases.
Focusing on aerodynamic characteristics of rigid coaxial rotor of a high-speed helicopter in hover and forward flight, a wind tunnel test is conducted in the 8 m ? 6 m low-speed straightflow wind tunnel of China Aerodynamics Research and Development Center. In the experiment,a 4 m diameter composite model rigid coaxial rotor is designed and manufactured, and firstorder flapping frequency ratio of the blade is 1.796 to ensure sufficient stiffness at the blade root.Rotor aerodynamic performance is measured under hovering and high advance ratio conditions.Also, the numerical method is used to calculate aerodynamic characteristics in typical states of the rigid coaxial rotor for analysis purpose. The rotor lift-drag ratio and lateral lift offset in the experiment are emphatically analyzed for the rigid coaxial rotor. The results indicate that in forward flight condition, the rotor lift-drag ratio first increases and then decreases with the increment of advance ratio and lift offset. When advance ratio remains constant, with the increment of lift offset, the lift-drag ratio of rigid coaxial rotor first increases and then decreases.
引文
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11.Bagai A.Aerodynamic design of the X2TMtechnology demonstrator main rotor blade.Proceeding of the 64th annual forum of American Helicopter Society.Alexandria:The AHS International,Inc.;2008.
12.Brown RE,Kim HW.Coaxial rotor performance and wake dynamics in steady and manoeuvring flight.Proceedings of 62th annual forum of the American Helicopter Society.Alexandria:The AHS International,Inc.;2006.
13.Lakshminarayan VK,Duraisamy K,Baeder JD.Computational investigation of coaxial rotor aerodynamics in hover.Proceeding of the 63rd annual forum of the American Helicopter Society.Alexandria:The AHS International,Inc.;2007.
14.Ye L,Xu GH.Calculation on flow field and aerodynamic force of coaxial rotors in hover with CFD method.Acta Aerodynamica Sinica 2012;30(4):437-42[Chinese].
15.Xu HY,Ye ZY.Numerical simulation of unsteady flow around forward flight helicopter with coaxial rotors.Chinese Journal of Aeronautics 2011;24(1):1-7.
16.Lorber PF,Law GK,Overview of S-97 RaiderTMscale model tests.Proceeding of the 72rd annual forum of the American Helicopter Society.Alexandria:The AHS International,Inc.;2016.
17.Pomin H,Wagner S.Navier-Stokes analysis of helicopter rotor aerodynamics in hover and forward flight.Journal of Aircraft2002;39(5):813-21.
18.Roe PL.Approximate rieman solvers,parameter vectors,and difference schemes.Journal of Computational Physics 1981;43(2):357-72.
19.Luo H,Baum JD,Loehner R.A fast,matrix-free implicit method for computing low Mach number flows on unstructured grids.International Journal of Computational Fluid Dynamics 2000;14(2):133-57.
20.Baldwin BS,Lomax H.Thin layer approximation and algebraic model for separated turbulent flows.Reston:AIAA;1978.Report No.:AIAA-1978-0257.
21.Steger JL,Dougherty FC,Benek JA.A chimera grid scheme multiple overset body-conforming mesh system for finite difference adaptation to complex aircraft configurations.Proceedings of the applied mechanics,bioengineering,and fluids engineering conference.New York:American Society of Mechanical Engineers;1983.p.59-69.
2.Go JI,Park JS,Choi JS.Validation on conceptual design and performance analyses for compound rotorcrafts considering liftoffset.International Journal of Aeronautical&Space Sciences 2017;18(1):154-64.
3.Harrington RD.Full-scale-tunnel investigation of the static-thrust performance of a coaxial helicopter rotor.Washington,D.C.:NASA;1951.Report No.:NACA TN-2318.
4.Mosher M,Peterson RL.Acoustic measurements of a full-scale coaxial helicopter.AIAA 8th aeroacoustics conference.Reston:AIAA;1983.
5.Fort F.An experimental investigation of hub drag on the XH-59A.Reston:AIAA;1985.Report No.:AIAA-1985-4065.
6.Yong LA,Graham DR.Experimental investigation of rotorcraft hub and shaft fairing drag reduction.Reston:AIAA;1986.Report No.:AIAA-1986-4065.
7.McAlister KW,Tung C,Rand O,Khromov V,Wilson J S.Experiment and numerical study of a model coaxial rotor.Proceedings of the 62nd annual forum of the American Helicopter Society.Alexandria:The AHS International,Inc.;2006.
8.Lim JW,McAlister KW,Johnson W.Hover performance correlation for full-scale and model-scale coaxial rotors.Journal of the American Helicopter Society 2007;54(3):1-14.
9.Coleman CP.A survey of theoretical and experimental coaxial rotor aerodynamic research.Washington,D.C.:NASA Ames Research Center;1997.Report No.:NASA-TP-3675.
10.Wayne J.Influence of lift offset on rotorcraft performance.AHSspecialist’s conference on aeromechanics.2008.
11.Bagai A.Aerodynamic design of the X2TMtechnology demonstrator main rotor blade.Proceeding of the 64th annual forum of American Helicopter Society.Alexandria:The AHS International,Inc.;2008.
12.Brown RE,Kim HW.Coaxial rotor performance and wake dynamics in steady and manoeuvring flight.Proceedings of 62th annual forum of the American Helicopter Society.Alexandria:The AHS International,Inc.;2006.
13.Lakshminarayan VK,Duraisamy K,Baeder JD.Computational investigation of coaxial rotor aerodynamics in hover.Proceeding of the 63rd annual forum of the American Helicopter Society.Alexandria:The AHS International,Inc.;2007.
14.Ye L,Xu GH.Calculation on flow field and aerodynamic force of coaxial rotors in hover with CFD method.Acta Aerodynamica Sinica 2012;30(4):437-42[Chinese].
15.Xu HY,Ye ZY.Numerical simulation of unsteady flow around forward flight helicopter with coaxial rotors.Chinese Journal of Aeronautics 2011;24(1):1-7.
16.Lorber PF,Law GK,Overview of S-97 RaiderTMscale model tests.Proceeding of the 72rd annual forum of the American Helicopter Society.Alexandria:The AHS International,Inc.;2016.
17.Pomin H,Wagner S.Navier-Stokes analysis of helicopter rotor aerodynamics in hover and forward flight.Journal of Aircraft2002;39(5):813-21.
18.Roe PL.Approximate rieman solvers,parameter vectors,and difference schemes.Journal of Computational Physics 1981;43(2):357-72.
19.Luo H,Baum JD,Loehner R.A fast,matrix-free implicit method for computing low Mach number flows on unstructured grids.International Journal of Computational Fluid Dynamics 2000;14(2):133-57.
20.Baldwin BS,Lomax H.Thin layer approximation and algebraic model for separated turbulent flows.Reston:AIAA;1978.Report No.:AIAA-1978-0257.
21.Steger JL,Dougherty FC,Benek JA.A chimera grid scheme multiple overset body-conforming mesh system for finite difference adaptation to complex aircraft configurations.Proceedings of the applied mechanics,bioengineering,and fluids engineering conference.New York:American Society of Mechanical Engineers;1983.p.59-69.