Vibration Analysis and Methods of Dry Friction Damping of Tubed Vortex Reducer

The tubed vortex reducer is a new structure of aero-engine, which is widely used in advanced large bypass ratio high performance turbofan engines. It is usually installed between the rear two-stage discs of the high-pressure compressor, and reduces the generation of free vortices by restricting the flow path of the cooling airflow, thereby reducing the pressure loss of the cooling airflow and improving the engine efficiency. In this paper, vibration analysis of tubed vortex reducer is carried out by experiments and numerical simulations. Using the finite element method, the natural vibration characteristics of the vortex reducer are calculated with ANSYS. The sensitivity analysis of the design parameters on the vibration characteristics is carried out, and the vibration laws of different components are obtained. In addition, the vibration test bench of the vortex reducer is set up, and the vibration test of the vortex reducer is carried out by means of frequency sweeping and hammer hitting respectively. Considering the effect of additional mass on the vibration of the vortex reducer, the experimental results satisfactorily reproduce the simulation results. Then the theoretical model of dry friction damping of vortex reducer is established and the relationship between friction work in different directions and its equivalent damping ratio is derived. The design method of damper sleeve of vortex reducer is proposed, and the dynamic model of a complex contact system composed of vortex tube and damping sleeve is established. Finally, The influence of the change of key structural design parameters and different installation methods on the damping ratio is analyzed. Overall,  this work can provide reference for vibration reduction design and engineering optimization of vortex reducer.