基于单扇区燃烧室试验的热声模拟方法研究及验证

Research and verification of thermo-acoustic simulation method based on single-sector combustion test

利用自主开发的热声网络模型研究了不同试验工况、出口边界条件、入口测量段长度对单扇区燃烧室试验台燃烧不稳定性的影响,并与试验结果进行了对比分析。结果表明:声学网络模型准确预测了不同试验工况的失稳频率。预测失稳频率与试验失稳频率相差±10 Hz以内,误差在2%以内。前期单扇区燃烧室试验表明,当入口测量段为0.4 m时,发生燃烧振荡,当入口测量段为0.25 m时,未发生燃烧振荡。数值模拟表明只有当入口测量段长度在0.35~0.44 m之间时,才会激发自激燃烧振荡,这很好地解释了上述试验结果。

An in-house developed thermo-acoustic network model was used to study the effects of different test conditions, outlet boundary conditions, and the length of inlet measurement section on the combustion instabilities of single sector combustion test rig, and the results were compared between simulations and tests.The results showed that the thermo-acoustic network model accurately predicted the unstable frequency at different test conditions.The differences between the predicted and test results were within ±10 Hz, and the errors were within 2%.The previous single-sector combustion chamber test showed that combustion oscillation occurred when the inlet measurement section was 0.4 m.Combustion oscillation did not happen when the inlet measurement section was 0.25 m. Numerical simulations showed that the self-excited combustion oscillation can be excited only when the length of the inlet measurement section was between0.35 m and 0.44 m,which explained the above test results well.