燃烧室热-声-结构耦合数值研究

Numerical Investigation of Thermal-acoustic-structural Coupling in Combustion Chamber

航空发动机燃烧室多种载荷间的交变作用是影响其工作稳定性及疲劳寿命的重要因素。应用有限元方法开展了燃烧室多场耦合数值研究,对比分析了不同网格质量、湍流模型、流体速度及材料属性等因素对模拟产生的影响,并运用ANSYS Workbench 14.0分别采用单向与双向耦合方式仿真分析了热-声-结构耦合作用下的结构动力特性。通过试验数据与模拟结果的对比分析,得出网格质量对计算时间和准确性影响较大,湍流模型主要影响温度、压力与速度等流场结果,而流体速度对流场温度和结构振动频率等具有较大影响;耦合作用产生的根源为燃烧不稳定性,热载荷较之声载荷对结构振动影响更大且在频率为275 Hz和385 Hz附近时耦合对振动影响较强。研究工作对燃烧室设计等具有重要实际意义。

Continuous coupling and alternating effects of a variety of loads in the combustor have an important influence on the fatigue damage when it＇s in operation. In order to analyze the mechanism of multi-physics coupling,numerical simulation by finite element method is implemented on the combustion chamber. Effects from different grids quality,turbulence models,fluid velocities and material properties on coupling simulation are discussed by comparison method. And simulations of one-way and two-way couplings are proceeded respectively to get the physical parameters of thermal-acoustic-structure coupling by application of ANSYS Workbench 14. 0. The conclusions that mesh quality has a large impact on the accuracy and efficiency of calculation,turbulence model mainly effects of the rationality of flow field change,and fluid velocity has an important influence on flow field temperature and structural vibration frequency are obtained by the comparative analysis of experimental data and simulation results. The generation root of coupling is combustion instability,thermal loads have a greater impact on the structure vibration than acoustic loads and the coupling near the frequencies of 290 Hz and 385 Hz has a stronger effect on vibration are also deduced. These works have an important significance for design of combustion chambers.