相较于传统尾桨结构，涵道尾桨系统呈现出更为复杂的气动耦合特性，主要表现为其旋转桨叶与环形涵道内壁、定子等固定部件之间产生的多重气动干扰现象。本文基于周期性边界条件与旋转参考系框架，建立了结合多块结构化网格生成技术及定常雷诺平均Navier-Stokes（RANS）方程的高精度数值模拟方法。通过对比SA365N1型海豚直升机涵道尾桨在悬停工况下总距5°至40°区间的气动载荷计算数据与试验数据，验证了数值方法的可靠性。在此基础上，系统性探究了桨叶扭转、桨叶弦长等几何特征，以及桨尖间隙对悬停气动性能的影响机理。研究表明：在较大桨叶负扭转的状态下，涵道所提供的拉力减小，进而引起悬停效率降低；当桨叶配置7°负扭转时，涵道尾桨气动效率可达到最优。弦长缩短至基准值的90%时，桨叶与涵道表面载荷显著降低；反之，当弦长增长至基准值的110%时，桨叶载荷虽有所提升，但增幅仅存在于桨尖局部区域，且提升幅度相对有限。进一步分析桨尖间隙的影响发现：较大的桨尖间隙尺寸将削弱涵道壁对流动的约束效应，导致桨尖流动强度加剧，并引发更为显著的扩散段流动分离现象，最终造成涵道尾桨悬停效率的损失；然而，过小的间隙会导致大总距下涵道内的质量流量减少，进而降低涵道尾桨整体性能。

Compared with conventional tail rotor configurations, ducted tail rotor systems exhibit more complex aerodynamic coupling charac-teristics, primarily manifested through multiple aerodynamic interference phenomena between rotating blades and fixed components such as annular duct walls and stators. This study establishes a high-fidelity numerical simulation method combining multi-block structured grid generation techniques and steady Reynolds-averaged Navier-Stokes (RANS) equations, based on periodic boundary conditions and a rotating reference frame framework. The reliability of the numerical approach was validated by comparing computa-tional aerodynamic load data with experimental measurements for the SA365N1 Dauphin helicopter ducted tail rotor under hover conditions across collective pitch angles ranging from 5° to 40°. Systematic investigations were conducted on the influence mecha-nisms of geometric parameters including blade twist, blade chord length, and tip clearance on hover performance. Key findings re-veal that excessive negative blade twist reduces the duct's contribution to thrust generation, consequently degrading hover efficiency, with optimal aerodynamic efficiency achieved at 7° negative twist. Chord length reduction to 90% of baseline significantly diminish-es blade and duct surface loading, while chord extension to 110% yields limited load enhancement confined to blade tip regions. Tip clearance analysis demonstrates that enlarged gaps weaken the duct's flow confinement effect, intensifying tip vortex strength and exacerbating flow separation in the diffuser section, thereby reducing hover efficiency. Conversely, insufficient clearance decreases mass flow rate at high collective pitch angles, compromising overall performance.