热声激励下燃烧室热声固耦合特性数值研究

Numerical study on thermoacoustic of combustion chamber subjected to thermoacoustic exciation

为研究燃烧室结构对热、声激励的响应,基于多场耦合瞬态模拟技术,建立燃烧室结构有限元模型,模拟了瞬态条件下热、声激励下燃烧室结构的热应力、温度场和结构应力。结果表明:受热声耦合作用的影响,靠近出口处的声压幅值下降约75%。燃烧室所受热应力与声压应力量级相同,两者对结构的影响皆不可忽略。燃烧室结构对声压的响应与声压激励频率有关。当激励频率接近燃烧室固有频率时,声压应力将显著提高并出现共振。

A simulation model has been established based on the multi-field coupling transient simulation technology in order to study the combuster structural response to the thermo-acoustic excitation.The thermal stress,temperature field and structural stress of combuster structure under thermal and acoustic excitation under transient conditions are simulated.The results show that,the acoustic pressure distribution at different locations within the combuster is uneven,and the amplitude of the acoustic pressure near the outlet is significantly reduced,the decrease is about 75%under the influence of thermoacoustic coupling.The thermal stress is the same as the sound pressure stress level,and the influence of both on the structure could not be neglected.The response of the combuster structure to the sound pressure is related to the frequency of the sound pressure excitation.When the excitation frequency is close to the natural frequency of the combuster,the sound pressure stress will be significantly improved.