Study on rubbing failure between fan vanes and spacer ring of a Turbo-Fan Engine

The objective of the present work is the study of the rubbing failure between fan stator vanes and the spacer ring of a Turbo-Fan Engine. The similar failures appeared 2 times in this small turbo-fan engine. The failure mechanism is analysed, in which kinds of factors that could influence the clearance between the rotor and the stator are taken into account. The failure is analysed by means of both test characterizations and numerical simulation techniques. Firstly, a finite element model of the spline joints is used to calculate the stiffness of the fan-rotor considering the influence of locating surface clearance. Secondly, a traveling wave vibration analysis of the spacer ring is performed, as well as the analysis of the stator vane. Finally, the analysis of the vibration test data is performed. The test characterizations and numerical simulation results indicate that, for Engine-1, the large 2× vibration shows a rotor misalignment, at the same time the traveling wave resonance of the spacer ring occurs, these cause the appearance of the failure. For Engine-2, the failure is caused by the rotor unbalance vibration. Some improvement measures are proposed to avoid this failure.