Study On Characteristic Of Pressure Fluctuation Of Aircraft Hydraulic System

Aircraft hydraulic system,as an important part of aircraft,is the power source of flight control system and landing gear,which determines whether the aircraft can take off safely.The pulsating flow output of the aircraft hydraulic pump will cause the pressure pulsation of the aircraft hydraulic system,and the pressure pulsation will cause the vibration and noise of the hydraulic system.In the vast majority of cases,pressure pulsation is harmful to the normal work of the hydraulic system,will reduce the life of the hydraulic system and components,serious will cause pipe wall rupture,support structure damage,resulting in support stiffness decline,pipeline system failure,hydraulic oil leakage,and even cause the machine destroyed.Therefore,it is of great significance for improving the safety of aircraft hydraulic system to study the mechanism and influencing factors of pressure pulsation and analyze the piping system under the action of pressure pulsation.Based on the aircraft hydraulic system as the research object,analyzes the mechanism of pressure pulsation,established the mathematical model of a typical hydraulic system,and the fluid-structure coupling model of hydraulic pipeline,with the analysis of related software,the influence factors of pressure pulsation and pressure pulsation pipeline under the action of features,and the fluid-structure interaction analysis of pipeline system is researched.The main research work is as follows:Firstly,the research background and significance of this paper are analyzed,the mechanism of pressure pulsation generated by the hydraulic system is analyzed in depth,the research on pressure pulsation characteristics of the hydraulic system at home and abroad is expounded,and the research content and structure of this paper are clarified.Secondly,the working condition of the hydraulic system was introduced,the working principle of the hydraulic pump was studied,the theoretical output flow of the hydraulic pump was deduced,the internal leakage path of the hydraulic pump and the calculation of internal leakage were analyzed,and the influence of machining and assembly errors on the leakage of each part was discussed.Finally,the actual output flow pulsation law of axial piston pump is obtained.Thirdly,establish a perfect mathematical model of the hydraulic system and establish a Simulink model of the model.Based on the model,the influence of each component parameter on the pressure pulsation is analyzed,and the pressure pulsation characteristics under different parameter Settings are given.Fourthly,the principle of aircraft hydraulic pipeline layout is introduced,and the fluid-solid coupling characteristics of the pipeline system are analyzed.The fluid-solid coupling mathematical model of hydraulic pipeline is established.Finally,fluid-solid coupling simulation analysis and experimental study of pipelines in aircraft hydraulic system were carried out.According to the finite element equation of aircraft hydraulic pipeline,the models of hydraulic system pipeline and flow field were established respectively,and the stress and displacement results of straight pipeline and curved pipeline were obtained by coupled calculation with MPCCI.The convection-solid coupling analysis is studied experimentally.