Based upon the turbulent Navier-Stokes equations, a CFD method is established to analyze the flow field and aerodynamic characteristics around the helicopter ducted tail rotor. In this method, a multi-block patched structured grid approach for predicting the flowfield of ducted tail rotor has been presented by considering the geometry characters of ducted tail rotor and the momentum-source model, and the multi-block grids are generated by solving the Poisson equations. On the basis of the known movements, geometric and aerodynamic characteristics about ducted tail rotor, the CFD method containing momentum-source terms is developed for the solution of N-S equations with S-A tur bulence model which can capture the vortex and flow separation phenomenon around the duct wall well. The calculat ed results about the flowfield of the ONERA M6 wing, coupled with thrust, induced velocities and load distributions of ducted tail rotor in hover, were compared with available experimental data for validation. By the present method, the flowfield and aerodynamic characteristics of the helicopter ducted tail rotor in hover, sideward flight and forward flight have been investigated respectively, some meaningful conclusions are obtained.%基于湍流Navier-Stokes方程,建立了一套直升机涵道尾桨流场及气动特性的CFD分析方法.在该方法中,针对直升机涵道尾桨流场的特点以及动量源方法对网格系统的要求,提出了一种多块对接网格生成方法,分块贴体网格采用求解Poisson方程的方法生成.通过结合涵道尾桨的运动方式、几何特征及气动特征,建立一个包含动量源项的N-S方程的涵道尾桨流场计算方法和迭代流程；为较好地捕捉涵道壁附近存在的旋涡及分离现象,采用了一方程S-A湍流模型.通过对ONERA M6机翼的绕流特性的计算分析,以及对涵道尾桨在悬停状态下的拉力、诱导速度、载荷分布等的计算分析,验证了该CFD方法的有效性.在此基础上,采用该方法进行直升机悬停、侧飞和前飞状态下涵道尾桨流场与气动特性的数值分析,得到了关于涵道尾桨流场和气动特性的一些有意义的结论.
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