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建立了基于气动/弹性耦合的旋翼桨涡干扰(BVI)气动和噪声分析方法。气动模型包括修正Beddoes尾迹模型和CFD模型,噪声计算采用基于声学类比法推导出的FW-H(Ffowcs-Williams Hawkings)方程,弹性桨叶动力学建模采用有限元方法。应用所建立的方法,对刚性的OLS(operational load survey)旋翼桨涡干扰状态的气动和噪声特性进行了计算,对比了两种气动模型在研究桨涡干扰问题的有效性;以弹性的HARTⅡ旋翼为研究对象,分析了桨叶弹性、时间步长对桨涡干扰气动载荷和噪声的影响。结果表明:进行桨涡干扰计算时所采用的时间步长不宜超过2°。CFD方法由于固有的数值耗散,计算出的OLS旋翼噪声声压峰值仅为试验值的60%,而修正Beddoes尾迹模型能够避免数值耗散,且具有高效率的优势。考虑桨叶气动弹性能够提高旋翼桨涡干扰噪声的预测精度。
Aeroelastic / elastic coupled aerodynamic and noise analysis of rotor vane vortex disturbance (BVI) is established. The aerodynamic model includes modified Beddoes wake model and CFD model. The FW-H (Ffowcs-Williams Hawkings) equation derived from acoustical analogy is used for noise calculation, and the finite element method is used for elastic blade dynamics modeling. The aerodynamic and acoustic characteristics of a rigid OLS (Rotor Propeller Vortex Interference) state were calculated by using the established method. The effectiveness of the two aerodynamic models in the study of the disturbance of the propeller vortex was compared with that of a rigid HART Ⅱ rotor As the research object, the influence of paddle elasticity and time step on the aerodynamic loads and noise disturbance of paddle vortex was analyzed. The results show that the time step used in the calculation of propeller vortex interference should not exceed 2 °. CFD method Due to the inherent numerical dissipation, the calculated OLS rotor noise sound pressure peak is only 60% of the experimental value, while the modified Beddoes wake model avoids numerical dissipation and has the advantage of high efficiency. Considering the aeroelasticity of the blade can improve the prediction accuracy of the rotor blade vortex interference noise.