Modeling And Analysis Of Coupled Vibration Of Double-pipe System Of Aero Engine

Vibration of hydraulic piping system of aeroengine mainly includes three aspects:the coupling vibration between casing and the pipelines, the coupling vibration between pipelines and the coupling vibration between conveying fluid and the pipeline. The study of FSI of single pipe is relatively mature, but the coupling vibration between pipelines makes the vibration of the whole system very complex, so that the FSI of single pipe model can’t fully support engineering. Therefore, research on the coupling vibration between pipelines has important significance.This research aims at the vibration mechanism of hydraulic pipes on the aero-engine so as to solve the oil leakage and crack problem of resonance. So accidents can be avoided. Based on Newton method, the nonlinear differential equation of FSI vibration has been established. On that basis, according to the classification of clamp the equations of double-pipe vibration have been established. The equations include visco-elastic coefficient and fluctuating flow factors, than the dimensionless equation was got. The influence of mass ratio, velocity of fluid and axial force on the natural frequency were researched by analyze the double-pipe vibration equation. Discretize the differential equation of the pipe motion by using Galerkin method. And then, by using the orthogonality of modal functions, the standard equation of the first order differential equations were got; the mathematical expression of pipe system critical velocity was deduced; the differences between complex modal Galerkin method and method were compared; the relationship curves between the natural frequency and parameters such as mass ratio were got. And the response of vibration amplitude of the pipe to aero-engine casing stimulation was analyzed. Through the numerical simulation of the aero-engine hydraulic pipe vibration, the response curve and the phase plane portrait of the system were obtained. Then, the stability of the system was analyzed.The conclusions of this paper correspond with the results obtained of FSI vibration of pipe conveying fluid. And the paper has better simulated the work environment of hydraulic pipe on aero-engine. The research can provide references for designing hydraulic pipe system of the aero-engine.