摘要
实验研究了贫燃预混分级火焰的燃烧不稳定性和火焰动力学特性。实验是在一个常温常压实验台上进行的,燃料为甲烷。通过对动态压力、热释放速率的快速傅里叶变换(FFT)分析,火焰图像的Abel逆变换、热释放积分、本征正交分解(POD)分析等方法,重点研究了分级比对燃烧不稳定性的影响。实验表明:预燃级燃料比例,对火焰的稳焰机制、热释放分布以及火焰的稳定性有至关重要的作用。随着分级比的提高,火焰由不稳定的脱体火焰或者蘑菇形火焰,变成稳定而紧凑的Ⅴ形火焰,火焰的热释放中心向喷嘴方向前移。POD分析表明,分级比较大时,预燃级火焰通过改善火焰根部的稳焰特性,进而削弱了火焰面周期性的膨胀和收缩,最终抑制了燃烧不稳定性。
The combustion instability and flame dynamics characteristics of the lean premixed graded swirl flame were experimentally studied.The experiment was carried out on a laboratory bench at room temperature and pressure fueled by methane.By means of fast Fourier transform(FFT) analysis of dynamic pressure and heat release rate, inverse Abel transformation of flame image, heat release integral, and proper orthogonal decomposition(POD) analysis, the effect of grade ratio on combustion instability was emphatically studied.The experimental results showed that the proportion of pilot stage fuel played an important role in flame stabilization mechanism, heat release distribution and flame stability.As the grade ratio increased, the flame changed from an unstable detached flame or mushroom flame to a stable and compact Ⅴ-shaped flame, with the heat release center of the flame moving towards the nozzle.POD analysis showed that when the grade ratio was relatively large, the pilot stage flame reduced the periodic expansion and contraction of the flame surface by improving the flame stability at the flame root, and finally inhibited the combustion instability.
作者
苏贺
郭志辉
SU He;GUO Zhihui(National Key Laboratory of Science and Technology on Aero-Engine Aero-thermodynamics,School of Energy and Power Engineering,Beijing University of Aeronautics and Astronautics,Beijing 100191,China)
出处
《航空动力学报》
EI
CAS
CSCD
北大核心
2021年第4期806-815,共10页
Journal of Aerospace Power
基金
国家科技重大专项(2017-111-0004-0028)。
关键词
分级旋流火焰
燃烧不稳定性
火焰动力学
压力脉动
本征正交分解
staged swirl flame
combustion instability
flame dynamics
pressure oscillation
proper orthogonal decomposition
