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为揭示单片桨叶控制(IBC)主动控制技术抑制旋翼桨-涡干扰(BVI)噪声的降噪机理,建立了一套基于CFD/CSD/FW-H_pds方程的综合噪声分析方法。旋翼桨-涡干扰噪声与旋翼桨叶载荷特性、气动变形以及旋翼桨尖涡结构等密切相关,为有效模拟旋翼桨叶的载荷特性及桨尖涡结构,将Navier-Stokes方程作为前飞流场的主控方程,空间离散上采用三阶MUSCL插值格式与通量差分裂Roe格式相结合;时间方向上采用双时间法,使用隐式LU-SGS格式在伪时间方向上进行推进;湍流模型采用对分离流动具有较好捕捉能力的Spalart-Allmaras模型。为提高旋翼桨叶弹性变形运动的模拟精度,建立了基于Hamilton变分原理的CSD模型,并与高精度的CFD求解器结合,发展了适合旋翼桨叶变形及载荷特性模拟的流固耦合分析方法。在CFD/CSD耦合方法分析流场基础上,使用可穿透空间积分面的FW-H_pds方法对旋翼气动噪声特性进行计算。首先,对流场及噪声数值方法进行验证;然后,着重针对UH-60A旋翼的斜下降飞行状态,分别对有/无IBC噪声主动控制条件下的旋翼BVI气动噪声特性进行了模拟,相位角、幅值和频率等不同控制参数的影响对比分析结果表明:IBC主动控制减小了前行侧桨叶表面尤其是桨叶尖部的负压峰值,降低了桨-涡干扰发生位置附近的桨叶气动载荷;同时主动控制后的桨尖涡集中程度变弱,并且增加了桨叶与桨尖涡之间的相遇距离,从而显著降低了桨-涡干扰噪声;选取合理的相位角、幅值和频率等主动控制参数组合,BVI噪声降低可达5~7dB。
In order to reveal the noise reduction mechanism of active rotor blade control (IBC) to suppress BVI noise, a comprehensive noise analysis method based on CFD / CSD / FW-H_pds equation was established. Rotor blade-vortex interference noise is closely related to the rotor blade load characteristics, aerodynamic deformation and rotor blade tip vortex structure. In order to effectively simulate the rotor blade’s load characteristics and tip-vortex structure, the Navier-Stokes equation is used as the forward flow field The main governing equations are discretized using the third-order MUSCL interpolation scheme and the flux-difference splitting Roe scheme. The dual-time method is used in the time direction and the pseudo-time is used in the implicit LU-SGS format. The turbulence model uses Spalart-Allmaras model with good ability to capture separated flow. In order to improve the simulation precision of rotor blade elastic deformation motion, a CSD model based on Hamilton variational principle is established and coupled with a high precision CFD solver, a fluid-solid coupling analysis method suitable for rotor blade deformation and load characteristics simulation is developed . Based on the CFD / CSD coupled flow field analysis, the rotor aerodynamic noise characteristics were calculated using the FW-H_pds method which can penetrate the space integral surface. First of all, the numerical simulation of flow field and noise is carried out. Then, the aerodynamic noise characteristics of rotor BVI under active control with / without IBC noise are simulated and the phase angle, The results of comparative analysis of the influence of different control parameters such as amplitude and frequency show that the IBC active control reduces the negative pressure peak on the front propeller surface, especially the tip of the propeller blade, and reduces the blade near the propeller-vortex disturbance And the aerodynamic load is reduced. At the same time, the degree of concentration of the tip vortex after active control is weakened, and the encounter distance between the vane and the tip vortex is increased, so the noise of the propeller-vortex interference is significantly reduced. The reasonable phase angle, amplitude and Frequency and other active control parameters, BVI noise reduction of up to 5 ~ 7dB.