Research On Unbalance Identification Method Of Turbocharger Rotor Based On Transient Response

With the rapid development of society,turbochargers are widely used in the field of automobile and aviation to improve the output power of the engine.On the one hand,because the turbocharger is driven by gas and rotates,the speed on the test table is unstable and will rise to a high speed in a very short time;On the other hand,the rotor of the turbocharger will be balanced at a low speed on the dynamic balancing machine before installation.However,the installation of the turbocharger requires the impeller end of the turbocharger to be removed before installation on the relevant equipment,which will destroy the balanced state of the impeller end and keep the original balanced state of the turbine end.Therefore,it is particularly important to study the whole machine high-speed dynamic balance of turbocharger rotor and the identification method of unbalance based on transient response.In order to verify the accuracy of the finite element model of the rotor system based on the transient unbalanced response and its solution method,the transient motion differential equations of the single-disk rotor system that consider the gyroscopic moment and damping of the rotor system is derived and is solved numerically by MATLAB in this paper;The finite element model of the single disk rotor system is established by ANSYS,and the transient solution of the finite element model is carried out;By comparing the numerical solution of the differential equation with the calculated results of the finite element model,it is found that the error of the calculated results of the finite element model of the rotor system's natural frequency,critical speed and transient unbalanced response are very small,and the accuracy of the finite element model of the rotor system based on transient unbalanced response and its solution method is successfully verified.Using correlation analysis method,this paper proposes an unbalance identification method based on transient response,and on this basis,puts forward an improved method for the unbalance identification-the average method;By analyzing the influence of double frequency noise and white gaussian noise on the unbalance identification,it is found that the correlation analysis method and average method can be used to eliminate the interference of the noise so as to accurately identify the unbalance of the rotor system;By analyzing the influence of different sampling frequencies on the unbalance identification,it is found that when the sampling frequency of the rotor system is greater than 6 times of the working speed,correlation analysis method based on transient response and average method can be used to accurately identify the unbalance of the rotor system.On the basis of the above theoretical research,this paper proposes a single surface unbalance identification method based on transient response for the rotor of turbocharger-single surface influence coefficient method.Finally,the unbalance identification method is verified by experiments.The simulation results are basically consistent with the experimental results,which proves the effectiveness and practicability of the method.