Study On Whole-body Vibration Characteristics Of Civil High-bypass-ratio Turbofan Engine

The vibration of the engine will not only affect the performance,but also damage its internal structure by the vibration stress.The engine vibration caused by unbalanced vibration of the rotor and other factors can be transmitted to the internal subsystems through the internal connecting parts in turn.The process of engine vibration transferring from one subsystem to another through connecting parts is a transfer path.It is necessary to control the vibration of the engine by controlling the main transmission path.The main research results of the civil large bypass ratio turbofan engine are as follows:First analyze the internal structure of the engine and build a 3D model of the engine using the modeling software UG.NX10.0And then introduce the basic principle and types of the transmission path analysis method,and select the operational transfer analysis method(OTPA)as the theoretical basis,establish the engine OTPA model.The vibration contribution analysis of the internal engine system is performed by the path insertion loss method.Analyze the influencing factors of the factors affecting the vibration transmission of the engine,find the influence law of the excitation frequency on the vibration of the whole engine and determine the stiffness of the bearing components.Verify the accuracy of the engine 3D model and OTPA model,and analyze the vibration load transfer path of the engine under different vibration excitation conditions by changing different vibration excitation inputs.The results show the 3-D model of engine vibration and OTPA model can be used for analysis after validating the accuracy of the model.The influence of excitation frequency on vibration of the whole machine is found through calculation,and the installation joints and bearing stiffness which effectively control the vibration of the engine are determined.At the same time,the transmission path of the engine is analyzed,and the general law of vibration load transmission in the engine under different input loads is obtained.