Dynamic characteristics analysis of blade-casing rubbing faults with abradable coatings

In this paper, a dynamic model of a 0-2-1 rotor system with rubbing fault between blade and abradable coated casings is developed. The sub-model of rubbing force considers scraping work energy of coating, casing stiffness, and initial clearance between blade tip and casing. A rotor rig is established and samples of abradable coatings are introduced into the rubbing experiment. Vibration characteristics of the rotor system under blade-casing rubbing fault are analyzed. Effects of rotating speed and initial clearance on the rub force and the system vibration are studied. Results show that the vibration of rotor focuses on the fundamental and multiple fundamental frequencies due to the blade-casing rubbing with the abradable coating. The multiple fundamental frequencies, the 2 x and 3 x in particular, are greatly affected by the rotating speed. The fractional harmonic frequencies are strongly influenced by the initial clearance between the blade tip and casing. Besides, the rotating speed and the initial clearance between the blade tip and abradable coating on the casing also affect the amplitude and distribution of the rub force.

Automated summary

This paper develops a dynamic model for a 0-2-1 rotor system with rubbing fault between blade and abradable coated casings. Experimentation on vibration characteristics with abradable coatings show that rotor vibration focuses on fundamental and multiple fundamental frequencies due to blade-casing rubbing. Multiple fundamental frequencies, especially 2x and 3x, are greatly affected by rotating speed, while fractional harmonic frequencies are strongly influenced by initial clearance. Rotating speed and initial clearance also affect the amplitude and distribution of rub force.