摘要
由阵风引起的动态载荷直接影响直升机的飞行品质和结构应力。为在详细设计阶段获得更加真实的直升机载荷信息,在时域中基于中等变形梁理论和非线性气动力模型建立了考虑机体和桨叶耦合效应的气动弹性模型。借助该模型对两种阵风下直升机悬停和前飞的飞行表现进行了考察,并将计算结果与孤立桨叶模型的计算结果进行了对比。在悬停状态下,当桨叶遭受向下的阵风,考虑耦合效应的模型和孤立桨叶模型中的桨根处剪切力以及桨盘的拉力系数均减小。且考虑机体耦合效应的模型计算数值小于孤立桨叶模型计算的数值。在前飞状态下,当模型添加阵风后,桨根剪切力增加,考虑机体耦合效应的桨盘升力系数减小。在前飞状态下,前进比为0.35的计算结果和前进比为0.2的计算结果不同。从计算结果来看,孤立桨叶模型计算结果偏保守。为获得更精确的阵风响应预测信息,必须考虑机体耦合效应。
Dynamic load due to gust exerted to helicopter rotors directly affects the structural stress and flight performance for helicopters. In order to obtain more realistic force information for helicopters in detailed design stage, a rotor fuselage coupled aeroelastic model in the time domain is constructed. A structure model based on medium deflection beam theory and a nonlinear dynamics model based LB model are built. In consideration of the effect of fuselage, coupled with structure and aerodynamics, this model is built to investigate the performance in hover and in forward flight with two kinds of gust. The calculation results are compared with the results of isolated rotors model. From the result of gust response calculation, it can be observed that, in hover state, when rotor suffers a downward gust, both shear force at the blade root and the thrust force coefficient decrease. The shear force of the rotor coupled with the fuselage is a little lower than the result of the isolated rotor. In the forward flight state, the shear force increases when a gust is added on the rotor. The thrust coefficient on the rotor disk for the rotor coupled with fuselage model decreases. The calculation result at the advanced ratio of 0.35 in the forward flight for the two models is different from the calculation response at the advanced ratio of 0.2. It can be concluded that the calculation result of isolated rotor is conservative. In order to provide more accurate response prediction, the fuselage coupled effect should be taken into consideration in calculation models.
作者
王林鹏
戴玉婷
唐长红
WANG Linpeng;DAI Yuting;TANG Changhong(School of Aeronautic Science and Engineering,Beihang University,Beijing 100191,China)
出处
《空气动力学学报》
CSCD
北大核心
2018年第6期1052-1060,共9页
Acta Aerodynamica Sinica
基金
国家自然科学基金(11672018
11402013)
关键词
直升机桨叶
气动弹性
动态载荷
阵风
机体耦合
helicopter rotor
aeroelasticity
dynamic load
gust
fuselage coupling
