关键词: 随机噪声干扰, 响应不确定性, 转子不平衡, 转速选择, 概率统计

Abstract: Whole engine dynamic balance during the assembly and trial run of aero gas turbine engine can improve the efficiency of dynamic balance. However, the complex transmission characteristics and multi-source excitations tend to induce significant randomness in the vibration responses of casing measuring points, which reduces the accuracy of the unbalance reversion. Therefore, a reverse method of equivalent unbalance of engine rotor based on the response of casing measuring points and considering complex transmission characteristics and random noise is proposed. Through the dynamic analysis of the whole engine, the transmission characteristics of the high-rotor unbalance excitation to the bearing position and the casing measuring point response are obtained. According to the probability distribution of the measured response, the unbalanced response with uncertainty is generated by superimposing the background noise of measured data and proportional noise varying with the fundamental frequency responses in the deterministic simulation response. Then, the response amplitude-frequency characteristics of the simulation and the actual measurements are matched, and the rotational speeds for unbalance reversion are selected. On this basis, A reverse method considering uncertain response and speed optimization is proposed to realize the reverse of unbalance with probability distribution. The simulation results show that the proposed method can suppress the deviation of the reversion results caused by the randomness of the response and improve the accuracy and stability of the reversion. Furthermore, the measured data are adopted for verification. The difference rate between the reversed response based on the equivalent unbalance obtained by the reverse method and the original response is significantly reduced compared with those obtained without this method, which verifies the engineering application potential of the proposed method.

Key words: random noise interference, response uncertainty, rotor unbalance, speed selection, probability and statistics