【作者】 张斌；

【导师】 杨卫东；

【作者基本信息】 南京航空航天大学 ， 工程硕士（专业学位）， 2018， 硕士

【摘要】 倾转旋翼机的回转颤振是旋翼挥舞产生的旋转平面内气动力与弹性机翼的弯曲和扭转发生耦合的振动发散现象,是限制倾转旋翼机最大飞行速度的主要原因之一。后期为提高回转颤振边界,提升最大飞行速度,V22机翼采用厚翼型加小展弦比的设计方案,利用提高机翼刚度的方法弱化倾转旋翼与机翼之间气动弹性耦合以达到提高前飞回转颤振临界速度的目的。V22为提高回转颤振临界速度而牺牲了巡航效率并付出了较大的结构重量代价。本文基于Hamilton原理,利用弹性机翼有限元模型,充分考虑外伸小翼气动力、惯性力和阻尼对系统的贡献,建立了倾转旋翼/短舱/外伸小翼/主机翼气动弹性耦合分析模型。通过回转颤振稳定性分析,预估分析模型的回转颤振临界速度和边界速度。同时,利用CFD软件对旋翼/外伸小翼之间的空气介质流动机理进行深入细致研究,为外伸小翼设计给出理论依据和指导。由于对称模态的回转颤振现象先于反对称模态出现,故本文设计了半展机翼的风洞实验缩比模型。通过对机翼大梁进行特殊设计,使机翼扭转刚度较低的同时保证机翼的垂向刚度和挠度,使其可在较低风速情况下实现回转颤振。利用3D打印技术设计制造不同几何参数的短舱外伸小翼,结合风洞试验,开展外伸小翼对回转颤振抑制的效果及设计参数的影响规律研究。研究结果表明,采用倾转短舱外伸小翼具有抑制倾转旋翼机回转颤振和提升巡航效率的潜力。更多还原

【Abstract】 Tiltrotor aircraft whirl flutter is one of the main reasons that limit the maximum flight speed of tiltrotor,which is the vibration divergence coupled with the aerodynamic force in the plane of rotation and the bending and twisting of the elastic wing caused by the blade waving.In the later stage,in order to increase the whirl flutter boundary and increase the maximum flight speed,the V22 wing adopts the design scheme of thick airfoil and small aspect ratio,and uses the method of increasing the wing stiffness to weaken the aeroelastic coupling between the tilting rotor and the wing.The purpose of increasing the critical speed of the front whirl flutter.The V22 sacrifices cruise efficiency and adds a significant structural weight penalty to increasing the critical speed of the whirl chatter.This paper is based on the Hamilton principle and uses the elastic wing finite element model,Full consideration of the contribution of the aerodynamic,inertial and damping forces of the outboard wing extensions to the system,established an aeroelastic coupling analysis model for tilting rotors,pylon,outboard wing extensions and wings.Through the analysis of whirl flutter stability,the critical speed and boundary velocity of the whirl flutter of the analytical model are estimated.At the same time,CFD software is used to study the air medium flow between the rotor and pylon outboard wing extensions in detail and to provide theoretical basis and guidance for the extensor wing design.Since the symmetrical modal whirl flutter occurs prior to the antisymmetric mode,this paper designs a wind tunnel experimental scaling model with half-spanned wings.The specially designed wing girder ensures a low torsional stiffness of the wing while maintaining the vertical stiffness and deflection of the wing,enabling it to achieve whirl flutter at lower wind speeds.Using the 3D printing technology to design and manufacture the pylon with different geometrical parameters,wind tunnel test was conducted to study the effect of outboard wing extensions on the suppression of whirl flutter and the influence of design parameters.The results of the study indicate that the use of pylon outboard wing extensions has the potential to suppress the whirl flutter of rotors and improve the cruising efficiency.更多还原