共轴双旋翼地面效应气动特性研究
发布时间：2018-08-19 10:43
【摘要】：地面效应对直升机的垂直起降及贴地飞行性能有显著的影响。目前,对地面效应的研究基本停留在单旋翼带尾桨构型,基于共轴双旋翼直升机的优势,其在未来将有很大的应用领域,因此本文对共轴双旋翼地面效应气动特性进行研究。论文基于时间步进算法建立了适用于共轴双旋翼气动特性研究的旋翼自由尾迹模型,并采用面元法模拟地面对周围流场的影响。在建模过程中,建立桨叶刚性挥舞运动模型,采用Weissinger-L一阶升力面模型考虑了桨叶的三维效应,并充分突出旋翼/旋翼和旋翼/地面之间的气动干扰,在稳定状态下对双旋翼系统配平分析并将各模型耦合进行数值迭代求解。本文发展的共轴双旋翼地面效应气动特性分析模型是在单旋翼自由尾迹模型的基础上建立的,可分析单旋翼和共轴双旋翼在地面效应状态的流场特性。通过已有的试验数据和本文试验研究得到的数据验证了本文数学模型的正确有效。最后论文利用经验证过的数学模型,先计算分析了地面效应下单旋翼悬停和前飞状态的旋翼气动特性,然后着重研究了水平地面和存在一定角度的倾斜地面影响下共轴双旋翼自由尾迹几何形状、流场特性和旋翼性能,地面的存在对旋翼周围流场存在一定的扰动,地面满足无穿透边界条件,其影响使旋翼下洗流径向扩展且向上卷起,对共轴双旋翼尤其是下旋翼的拉力产生明显的影响。通过对共轴双旋翼的气动干扰特性进行了计算分析研究,得到了一些有意义的结论。
[Abstract]:The ground effect has a significant effect on the vertical take-off and landing performance of the helicopter. At present, the research on ground effect basically stays on the configuration of single rotor with tail propeller. Based on the superiority of coaxial double rotor helicopter, it will have a very large application field in the future. Therefore, the aerodynamic characteristics of ground effect of coaxial double rotor are studied in this paper. Based on the time stepping algorithm, a rotor free wake model for the study of the aerodynamic characteristics of a coaxial double rotor is established in this paper, and the surface element method is used to simulate the influence of the flow field around the rotor. In the process of modeling, the rigid motion model of blade is established, and the Weissinger-L first order lift surface model is used to consider the three-dimensional effect of the blade, and the aerodynamic interference between rotor / rotor and rotor / ground is fully highlighted. In the stable state, the double rotor system is equalized and each model coupled is solved by numerical iteration. The analytical model of ground effect of coaxial double rotor is established on the basis of the free wake model of single rotor, which can be used to analyze the flow field characteristics of single rotor and coaxial double rotor in ground effect state. The validity of the mathematical model is verified by the existing experimental data and the experimental data obtained in this paper. Finally, based on the verified mathematical model, the aerodynamic characteristics of the rotor with ground effect in hovering and forward flight states are calculated and analyzed. Then, the free wake geometry, flow field characteristics and rotor performance of the coaxial biaxial rotor under the influence of horizontal ground and inclined ground with certain angles are studied. The presence of the ground has some disturbance on the flow field around the rotor. The ground satisfies the condition of non-penetrating boundary, and its influence makes the downward wash flow of rotor expand radial and roll up, which has an obvious effect on the pull force of the coaxial double rotor, especially the lower rotor. The aerodynamic interference characteristics of coaxial double rotor are calculated and analyzed, and some meaningful conclusions are obtained.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：V211.52
[Abstract]:The ground effect has a significant effect on the vertical take-off and landing performance of the helicopter. At present, the research on ground effect basically stays on the configuration of single rotor with tail propeller. Based on the superiority of coaxial double rotor helicopter, it will have a very large application field in the future. Therefore, the aerodynamic characteristics of ground effect of coaxial double rotor are studied in this paper. Based on the time stepping algorithm, a rotor free wake model for the study of the aerodynamic characteristics of a coaxial double rotor is established in this paper, and the surface element method is used to simulate the influence of the flow field around the rotor. In the process of modeling, the rigid motion model of blade is established, and the Weissinger-L first order lift surface model is used to consider the three-dimensional effect of the blade, and the aerodynamic interference between rotor / rotor and rotor / ground is fully highlighted. In the stable state, the double rotor system is equalized and each model coupled is solved by numerical iteration. The analytical model of ground effect of coaxial double rotor is established on the basis of the free wake model of single rotor, which can be used to analyze the flow field characteristics of single rotor and coaxial double rotor in ground effect state. The validity of the mathematical model is verified by the existing experimental data and the experimental data obtained in this paper. Finally, based on the verified mathematical model, the aerodynamic characteristics of the rotor with ground effect in hovering and forward flight states are calculated and analyzed. Then, the free wake geometry, flow field characteristics and rotor performance of the coaxial biaxial rotor under the influence of horizontal ground and inclined ground with certain angles are studied. The presence of the ground has some disturbance on the flow field around the rotor. The ground satisfies the condition of non-penetrating boundary, and its influence makes the downward wash flow of rotor expand radial and roll up, which has an obvious effect on the pull force of the coaxial double rotor, especially the lower rotor. The aerodynamic interference characteristics of coaxial double rotor are calculated and analyzed, and some meaningful conclusions are obtained.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：V211.52
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