Vibration Test Method of Aero-Engine 3D Printing Pre-Swirl Nozzle

Abstract

According to the installation environment of the pre-swirl nozzle in the aero-engine, the equivalent constraint fixture is designed, which is the special fixture for vibration test. The equivalent constraint fixture has been checked in three aspects: stiffness simulation ring stiffness check, modal matching check and equivalent constraint fixture strength check. The modal characteristics of the pre-swirl are tested by hammering modal test method, and the natural frequency, mode shape and damping ratio are obtained within 2200Hz. By comparing the modal test results with the simulation results, the mode shapes are consistent. The maximum error of natural frequency is the 1st order 6 pitch diameter, , and the minimum error of the natural frequency is the 1st order 2 pitch diameter. The main frequency of the pre-swirl nozzle is determined to be 665.029Hz by frequency sweep test. The error of the result compared with the modal test result is 3.30%, and the error compared with the simulation result is only 1.59%. The excitation mode of pre-swirl nozzle formal durability test is determined by the pre-test. Finally, it is concluded that the vibration fatigue life of the pre-swirl nozzle can reach 5×10 7 times under a given stress level (120MPa).