摘 要：与传统尾桨相比，剪刀尾桨因调制效应具有一定的降噪优势，但上、下旋翼间气动干扰诱发了气动效率损失问题。为了揭示剪刀尾桨的气动干扰机理，本文结合嵌套网格技术，构建了基于非定常雷诺平均Navier-Stokes方程的剪刀尾桨高精度流场数值模拟方法，开展了悬停状态下剪刀尾桨上、下旋翼气动干扰特性研究。系统分析了剪刀角、翼型、后掠桨尖等外形和布局参数对气动特性的影响规律，提出上、下旋翼不同总距配置、不同桨盘半径等非常规剪刀尾桨构型，并开展了气动干扰特性分析。结果表明：在总距不变的前提下，“U”型剪刀尾桨整体拉力与剪刀角呈现正相关，上、下桨盘拉力呈现此消彼长的变化特性；通过对比三种典型直升机尾桨翼型，OA翼型应用于剪刀尾桨中时悬停效率最佳；采用后掠构型虽不会提高剪刀尾桨的最大悬停效率，但可延缓尾桨的桨尖失速。非常规构型方面，通过实施下桨盘半径增大10%的改进方案，可使最大悬停效率较常规构型提升12.5%；合理调整下桨盘总距（较上桨盘增加2°）能优化载荷分配，实现整体效率2.4%的增益。
Abstract: Compared with conventional tail rotors, scissor tail rotors exhibit certain noise reduction advantages due to their modu-lation effect, but suffer from aerodynamic efficiency loss caused by aerodynamic interference between upper and lower rotors. To improve the aerodynamic efficiency of scissor tail rotors, this paper employs overset grid technology to establish a high-precision numerical simulation method based on unsteady Reynolds-averaged Navier-Stokes (URANS) equations, investigating the aerody-namic interference characteristics of scissors tail rotors in hover. The research systematically analyzes the influence of configuration parameters including scissor angle, airfoil type, and swept blade tips on aerodynamic performance. Unconventional configurations featuring differential collective pitch settings and varying rotor disk radii between upper and lower rotors are proposed and evaluated. Results indi-cate that: Under constant total collective pitch, the "U"-type scissor tail rotors total thrust shows positive correlation with scissor angle, while upper and lower rotor thrusts demonstrate a seesaw relationship; Moreover, among three typical helicopter tail rotor airfoils, the OA airfoil achieves optimal hover efficiency. Additionally, swept blade tip configuration delays tip stall without improving maximum hover efficiency. Regarding unconventional configurations: Increasing lower rotor radius by 10% enhances maximum hover efficiency by 13% compared to conventional designs; Appropriately adjusting lower rotor collective pitch (+2° rela-tive to upper rotor) optimizes load distribution, achieving 2% overall efficiency gain.
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