Modification Of Friction Term For The 14-equations Of Fluid-structure Interaction Vibration Of High Speed And High Pressure Hydraulic Pipeline

With the development of the hydraulic system to high pressure and high speed,the damage of fluid-structure interaction vibration of hydraulic pipeline becomes more obvious.With the increase of flow velocity,the turbulent flow appears inside the hydraulic pipeline,which will cause the vibration mechanism of pipeline with high speed and high pressure to be more complex.So focus on the mechanism and the interface effect of fluid-structure interaction vibration,the friction model was corrected with the turbulence was taken into consideration in this paper.And the fluid-structure interaction vibration characteristics were compared under different flow state,such as laminar flow and turbulent flow.All of the research works will provide guidance for the optimization of the aero hydraulic pipeline.The main research work and content are as follows.(1)With the adequate investigation of fluid-structure interaction vibration,we found that the fluid-structure interaction vibration of hydraulic pipeline is a common problem of pipeline systems,and a lot of innovative research works had been put forward by scholars at home and abroad.However,the researches under high speed and high pressure are rarely to see,and the friction coupling is always to be neglected.Therefore,this paper introduced the friction coupling term into the analysis to improve the solving precision of the fluidstructure interaction vibration dynamic behaviors.And the research work on the modification of the friction term was carried out under high speed and high pressure.(2)The 14-equations model of aero hydraulic pipeline under high speed and high pressure was built up with the effect of friction coupling was taken into consideration.The boundary constraint matrix,the excitation matrix and the coordinate rotation matrix were established to simulating the real working conditions of an aero hydraulic pipeline.And the dynamic behaviors were solved with the transfer matrix method which was performed by MATLAB program.(3)The comparison between the steady flow model and the transient flow model was completed based on the theory of friction coupling.And expression of the shear friction which is suitable for not only steady flow but also transient flow was put forward on the base of unsteady friction model.At last the friction model was corrected.(4)The axial vibration response characteristics of an aero hydraulic pipeline of the domestic large aircraft C919 were analyzed based on.the friction model which was obtained above.And during such an analysis,the flow and pressure parameters were considered to simulating the real working conditions of airplane.(5)The experimental testing for fluid-structure interaction vibration of an aero hydraulic pipeline was completed.The axial vibration response of the aero hydraulic Pipeline under laminar flow and turbulent flow were obtained by adjusting the flow velocity.And the experimental results were used to verifying the correctness of the simulation analysis.