Research On Vibration-Acoustic Coupling Characteristics Of Combustion Chamber

Acoustic-structure coupling characteristics study is now a key study direction. It is often working in high temperature and pressure environment, and prone to failure of structural damage and acoustic fatigue damage, seriously affect on the life of the combustion chamber. Aircraft engine combustion instability is not only the main reason for affecting its work stability, but also cause the combustion chamber wall structure vibro-acoustic coupling fatigue damage. And there are some closely connections between the vibro-acoustic coupling mode and the combustion instability. Therefore, in order to prolong the life of the combustion chamber, studying of acoustic-structure coupling characteristic in the combustion chamber is necessary.In this paper, the model of the combustion chamber wall structure is built by finite element method, and the structure modal of the combustion chamber wall structure, acoustic modal and acoustic-structure coupling modal are calculated to study the effects on acoustic-solid coupled of combustion chamber by structure modal and acoustic modal. Structure mode of the combustion chamber has a little influence on the fluid-solid coupling modal, only weak coupling happened.Acoustic modal of combustion chamber had a greater influence on the solid coupling modal with the strong coupling by a new mode.Its vibro-acoustic coupling characteristics are researched in different fluid densities, different velocity and different wall thicknesses through analysis the combustion chamber wall structure for harmonic response. Second, natural frequencies by experimentally derived and mode shapes of the finite element results are verified, a good validation of the finite element results is correct. Finally, CFD simulation of the combustion chamber combustion characteristics.it is applied to the combustion chamber wall structure with finite element calculation of its natural frequency by calculating the combustion pressure and combustion temperature.This paper studies the structural and acoustic coupled characteristics of the combustion chamber, it has an important application value for the study of sound and solid coupled and increase structural strength of combustion chamber.