发动机篦齿-橡胶涂层碰摩转子振动特性实验研究

Experimental Study on Vibrational Characteristics Induced by Rubbing Between Labyrinth and Rubber-Coating for Aero-Engine

关键词:  航空发动机  软碰摩  振动特征  轴心轨迹  进动分析

Key words:  Aero-engine  Soft-rubbing  Vibrational characteristics  Shaft orbit  Whirl analysis

摘要:

转静碰摩是航空发动机的多发故障，其引起的转子振动特性受转静碰摩材料的影响。考虑了碰摩机匣的硫化橡胶软涂层，实验研究了发动机增压级封严篦齿与封严机匣之间的渐进式碰摩，分析了转静碰摩过程中的转速、振动位移波形、轴心轨迹和进动特征的变化规律。结果表明：封严篦齿与橡胶涂层机匣的碰摩可分为四个阶段，转子转速经过了掉转-超加速-波动恢复-过减速的过程，振动位移波形在转速掉转阶段变化最明显，轴心轨迹呈现稳定-不稳定-稳定的变化规律，篦齿-橡胶软碰摩激起了转静子局部共振，表现为正反进动的高阶超次谐频，碰摩同时引起了对正反进动基频和低阶倍频的频率调制，增压级转静碰摩对涡轮端振动的影响相对较弱。

Abstract:

Rotor-stator rubbing is common in aero-engines， and the induced rotor vibrational characteristics are affected by the rubbing materials. The soft coating made by vulcanized rubber is considered for rubbing case， followed by the experimental investigations on the kind of progressive rubbing between the seal-labyrinth and the seal-case of aero-engine booster. The rotating speed， vibrational displacement waveforms， shaft orbits and whirl features during the rubbing process are analyzed. In the results， four variation-phases are observed for the investigated rubbing， wherein the rotating speed experiences a period of uncontrolled-deceleration， super-acceleration， oscillating-recovery， and excessive-deceleration. The most significant changes of vibrational displacement waveform are captured in the uncontrolled-deceleration phase. The shaft orbit varies from stable to unstable， and recovers to be stable finally. High-order superharmonics （corresponding to the resonance of the rotor and stator）， the modulations of the fundamental frequency and low-order harmonics of forward whirl and backward whirl are excited by the soft rubbing. The vibrations at the turbine end are slightly impacted by the rubbing at the booster end.