李志彬, 曹亚雄, 林永峰, 等. 旋翼悬停状态形变特性及其对噪声的影响[J]. 空气动力学学报, 2022, 40(5): 71−78. doi: 10.7638/kqdlxxb-2021.0047
引用本文: 李志彬, 曹亚雄, 林永峰, 等. 旋翼悬停状态形变特性及其对噪声的影响[J]. 空气动力学学报, 2022, 40(5): 71−78. doi: 10.7638/kqdlxxb-2021.0047
LI Z B, CAO Y X, LIN Y F, et al. Deformation characteristics of a hovering rotor and its influence on the aerodynamic noise[J]. Acta Aerodynamica Sinica, 2022, 40(5): 71−78. doi: 10.7638/kqdlxxb-2021.0047
Citation: LI Z B, CAO Y X, LIN Y F, et al. Deformation characteristics of a hovering rotor and its influence on the aerodynamic noise[J]. Acta Aerodynamica Sinica, 2022, 40(5): 71−78. doi: 10.7638/kqdlxxb-2021.0047

旋翼悬停状态形变特性及其对噪声的影响

Deformation characteristics of a hovering rotor and its influence on the aerodynamic noise

  • 摘要: 为研究桨叶弹性形变对旋翼气动噪声的影响,基于Camrad Ⅱ软件和FW-H方程,建立了考虑桨叶弹性形变的旋翼悬停气动噪声计算模型。其中,桨叶弹性形变量采用Camrad Ⅱ的弹性桨叶模型计算,形变桨叶外形采用三维网格精确描述,结合Camrad Ⅱ计算得到的旋翼非定常气动载荷,最后基于FW-H方程进行了形变旋翼悬停噪声的计算分析。同时,在风洞中采用双目立体视觉方法对模型旋翼进行形变测量试验,通过Camrad Ⅱ的仿真数据与试验数据的对比分析,发现仿真数据与试验数据基本吻合,验证了Camrad Ⅱ具有较好的可靠性,能够准确预估悬停状态下桨叶的弹性形变量。全尺寸旋翼的悬停噪声计算结果表明:在典型工作状态下,旋翼桨叶会发生明显的弹性形变,尤其在挥舞方向;桨叶形变不会改变旋翼悬停气动噪声的方向特性;在噪声的主要传播方向上,桨叶形变对厚度噪声和载荷噪声均会产生作用,进而导致总噪声的最大变化量约1.0 dB。通过本文研究表明,在对旋翼气动噪声,尤其是载荷噪声成分进行精确计算时,考虑桨叶的弹性形变是非常必要的。

     

    Abstract: In order to study the influence of blade elastic deformation on rotor aerodynamic noise, based on Camrad Ⅱ and the FW-H equation, an aerodynamic noise calculation model that takes the blade elastic deformation into account has been established for a rotor in hover. The elastic blade model in Camrad Ⅱ is used to calculate the elastic shape variation of the blade. A three-dimensional grid is used to accurately describe the deformed blade. Combined with the unsteady aerodynamic load of the rotor obtained by Camrad Ⅱ, the hovering noise of the deformed blade is calculated and analyzed based on the FW-H equation. The binocular stereo vision method is used to measure the deformation of the model rotor in a wind tunnel. It is found that the numerical results are agree reasonably well with the experimental data, which verifies that Camrad Ⅱ has a good reliability and can accurately predict the elastic shape variation of the blade in hover. The hover noise characteristics of the full scale rotor are further calculated and analyzed. The results show that under typical working conditions, the rotor blade has obvious elastic deformation, especially in the flap direction. The blade deformation does not change the directivity of the noise in hover. However, it affects the thickness and loading noise in the main propagation direction, resulting in a maximum variation of about 1.0 dB in the total noise. Consequently, the influence of the blade elastic deformation should be considered for obtaining more accurate aerodynamic noise.

     

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