Some influencing factors of rotor vibratory loads prediction under high speed state
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摘要: 依据直升机大速度前飞状态的气动环境和桨叶运动,分析了非定常气动力模型、动态失速模型、诱导速度分布、桨叶弹性变形、桨毂力合成以及数值计算方法对旋翼振动载荷预计的影响.将Leishman和Beddoes气动模型、动态入流理论和桨叶挥舞运动综合计入载荷模型中,采用状态空间法对方程进行离散化处理,编制了相应的计算程序.计算结果表明采用不同的分析模型对旋翼振动载荷预计有较大影响,翼型失速是主要影响因素.Abstract: Based on the rotor airflow environment and blades movement, which would be produced when the helicopter flighted forward with high speed. It was analyzed the influence on the hub vibratory loads prediction by unsteady aerodynamics model, dynamic stall model, induced-flow distribution, elasticity deformation of blade, synthesization of hub loads and the method of numerical calculation. The hub load model includes the Leishman-Beddoes unsteady dynamic stall model, dynamic inflow theory and coupled blade movement between flap and torsion. The state-space method was used to solve the equation, which was fit for computer calculation. A calculation program was built up. Comparing calculational results of several models, it is revealed that various analysis models have great influence on hub vibratory loads prediction precision, and that aerofoil stall and induced velocity distribution are primary influencing factors. It is appropriate that more advanced induced inflow model and unsteady aerodynamics are introduced in hub vibratory loads prediction.
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Key words:
- rotors /
- vibration /
- dynamic loads /
- unsteady flow
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