某型航空发动机环形燃烧室火焰筒声学模态分析

燃烧不稳定不仅影响航空发动机的工作稳定性,而且还是造成燃烧室火焰筒薄壁结构声振耦合疲劳破坏的重要原因.燃烧不稳定性的非稳态运动与燃烧室火焰筒的固有声学振型密切相关,因此对燃烧室火焰筒进行声学特性分析具有重要意义.为此建立了航空发动机环形燃烧室火焰筒声学有限元模型,分析了燃烧室火焰筒的声学特性.分别对常温常压下和高温高压下燃烧室火焰筒的声学模态进行了分析,获得了相应的声学固有频率和振型,为发动机燃烧室结构抗疲劳设计提供了参考.

Acoustic modal analysis applied to aero - engine annular chamber flame tube

Combustion instability not only will affect the stability of aero-engine,but also can destroy the thin wall structures of combustor flame tubes.Since there are some connection between the acoustic mode and the combustion instability,it is necessary to analyze acoustic modal of the aero-engine annular chamber flame tubes.In this paper,the finite element method(FEM) model of combustion chamber flame tube cavity is built.Under the circumstance of normal room temperature and pressure,the acoustic mode under closed and open state is simulated.And so does it under the high temperature and high pressure.Then the numerical results of acoustic oscillation frequency and the acoustic mode shape are obtained.The analyzing method and the calculated results are of great significant for analyzing the panel structure sonic fatigue problem,and provide the theoretical basis.