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针对航空发动机气膜阻尼的结构设计需求,基于挤压间隙流理论和能量方程建立气膜阻尼的力学模型,由此获得气膜阻尼结构的等效刚度系数和等效阻尼系数,通过振动方程的理论推导获得放大因子的表达式.结果表明:气腔厚度、气腔初始压强、吸振薄板模态频率和安装位置是影响减振效果的关键参数.气腔最优厚度主要由附面层厚度和实际振动频率决定,需结合实际情况确定气腔厚度,以最大程度降低振动响应;气腔初始压强越高,阻尼系数越大;吸振薄板的固有频率应尽可能与叶片本体接近,并且安装在本体振动响应最大位置,以取得最好的减振效果.
Aiming at the structural design requirements of aero-engine aerofoil damping, the mechanical model of aerofoil damping is established based on the theory of squeezing gap flow and energy equation, and the equivalent stiffness coefficient and equivalent damping coefficient of the aerodynamic damping structure are obtained. The theoretical derivation obtains the expression of magnifying factor.The results show that: the thickness of the gas cavity, the initial pressure of the gas cavity, the mode frequency of the vibration-absorbing sheet and the installation position are the key parameters that affect the damping effect.The optimum thickness of the gas cavity is mainly determined by the thickness The actual vibration frequency is determined, the air chamber thickness needs to be determined according to the actual situation to minimize the vibration response; the higher the initial pressure of the air chamber, the larger the damping coefficient; the natural frequency of the vibration-absorbing sheet should be as close as possible to the blade body, Vibration response to the maximum position, in order to obtain the best damping effect.