积冰对飞机本体纵向非线性动力学稳定域的影响

摘要

Icing may threaten flight safety,so the research on the effect of icing on aircraft stability is of great significance in ensuring flight safety.Ice reduces the stall angle of attack.Only studying the stability of a small angle of attack in the linear segment is not sufficient,so it is necessary to investigate the nonlinear dynamic stability region of the aircraft.Firstly,a nonlinear dynamics model of iced aircraft's longitudinal motion is built based on the aerodynamic coefficient curves under icing condition.Then,the stability region boundary of the aircraft's longitudinal motion is constructed according to the nonlinear dynamics theory,and is verified by time-domain simulation.Finally,the influence of icing on the stability region of the aircraft is analyzed through comparing the change of the stability region under ice-free and icing conditions,and the effects of icing on the stability region and the aerodynamic coefficients are compared.Under icing condition,the stability region shrinks by about 20 percent in the pitch velocity direction,and the maximum angle of attack on the boundary of stability region decreases by about 1 degree.The results show that the change of the stability region of the aircraft is consistent with the change of the aerodynamic coefficient under icing condition,which leads to a smaller stability region or even flight accident.%积冰威胁飞行安全,研究积冰对飞机稳定性的影响对确保飞行安全具有重要意义.积冰导致飞机失速迎角降低,仅研究飞机在小迎角线性段的稳定性是不充分的,还需对其非线性动力学稳定域进行研究.首先,基于积冰条件下的飞机气动系数曲线,建立积冰飞机纵向运动的非线性模型;然后,根据非线性动力学理论构造出飞机纵向运动的稳定域边界,并利用时域仿真对稳定域边界进行验证;最后,通过对比无冰与积冰条件下稳定域的变化,分析积冰对飞机稳定域的影响,并将积冰对飞机稳定域的影响和其对气动系数的影响进行对比.积冰条件下飞机稳定域在俯仰角速度方向上收缩约20％,稳定域边界处的最大迎角减小约1°.研究结果表明,积冰条件下飞机稳定域的变化与气动系数的变化一致,积冰导致飞机的稳定域缩小,容易引起飞行事故.