Abstract: A new method for rub fault detection based on electrostatic technique is discussed for online monitoring of blade rub in aeroengine. The generation process and charging mechanism of blade rub debris are first analyzed, and then the electrostatic probe theory and characteristics of electrostatic induction of a point charge are presented. After that a periodical rub detection model is established. The model shows that a series of characteristic frequencies which decay greatly over frequency will appear in the sensor output signal when periodical rub occurs. Two simulated rub experiments are performed with an electrostatic sensor. The result of the first experiment shows that rub debris could be detected by the sensor, while the activity level (AL) significantly increases and the event rate (ER) does not change during the rub. The second experiment shows that the characteristic frequency and its double frequency in the signal and the amplitude decay greatly over frequency. Thus, the validity of the periodical rub detection model is proved.

Key words: aeroengine, rub fault, electrostatics, model, experiment