贫预混燃烧室燃烧稳定性的数值研究

Numerical Study on Combustion Stability in a Lean Premixed Combustor

关键词:  贫预混燃烧  旋流强度  燃烧不稳定  抑制方法

Key words:  Lean premixed combustion  Swirl intensity  Combustion instability  Suppression method

摘要:

为了深入探究贫预混燃烧中的燃烧不稳定特性并发展有效的控制方法，通过数值模拟的方法，详细分析了当量比、旋流数、预混气初温对燃烧不稳定的影响规律，并尝试把穿孔板背腔用于模型燃烧室燃烧不稳定的控制研究中。研究发现该模型燃烧室的压力振荡为径向自激振荡模式，旋流强度和当量比对贫预混燃烧的稳定性具有重要影响作用，预混气初始温度的不同，对室内的一阶振荡频率和声压级影响不大，穿孔板背腔可以用来抑制燃烧室内的不稳定现象，当穿孔板背腔长度增加到60mm时，室内的声压级降低了19.35%。

Abstract:

In order to explore the characteristics of combustion instability and develop effective control methods，the combustion instability phenomenon，which happens in lean premixed combustion，was investigated. In the numerical simulation，the effects of equivalent ratio，swirl number，and initial temperature of premixed gas on instability combustion were emphasized，and the perforated liners were used in the control of combustion instability. Research results show that the pressure oscillation mode is radial self-excited oscillation mode in the combustion chamber. The equivalence ratio and swirl intensity have an important influence on the combustion stability. The initial temperature of premixed gas has little effect on the first order oscillation frequency and sound pressure level in the combustion chamber. The perforated liners can be used to suppress the combustion instability，especially，when the length of the perforated plate increased to 60mm，the sound pressure level in the chamber is reduced by 19.35%.