关键词: 燃烧室, 薄壁结构, 有限元, 声振耦合

Abstract:

The vibro-acoustic coupling affected combustion stability of the chamber, augmented chamber structure fatigue damage. Therefore, the study of vibro-acoustic coupling characteristics of a combustion chamber structure was essential for its design to increase combustion stability and resist fatigue damage. A three dimensional structural-acoustic model was built by using finite element software to study the vibro-acoustic coupling characteristics of a closed structure combustor, and then the natural frequencies and modal shapes were worked out. The combustor acoustic-structure transfer functions were measured in the experiments, while the natural frequencies and modal shapes of the combustor structure within vibro-acoustic coupling were obtained.The results show that the acoustic field, which produces special coupling frequencies, is equivalent to the additional mass added to the structure and reduces the natural frequency of the structure. The experiments verify the correctness of the finite element calculation results, may provide a basis for the design of the combustor liner thin-walled structure.

Key words: combustion chamber, thin-walled structure, finite element method, vibro-acoustic coupling