弱旋流燃烧器流场特征和污染排放研究

关键词:弱旋流燃烧器；丁烷；贫油熄火；排放；激光诱导荧光

关键词:  弱旋流燃烧器  丁烷  贫油熄火  排放  激光诱导荧光

Key words:  Low swirl burner  Butane  Blow off  Emissions  Particle image velocimetry

摘要:

弱旋流燃烧技术具有极低的NO_x污染排放能力，是未来燃气涡轮发动机低排放贫油预混燃烧组织方案之一。为了深入理解弱旋流流场特征和燃烧稳定性，建立了采用弱旋流燃烧器的试验装置，设计了不同几何尺寸的叶片式旋流器，采用PIV方法分析了旋流数0.43，0.49和0.55的流场基本特征。以丁烷为燃料获得了稳定的弱旋流火焰，采用激光诱导荧光技术测量了火焰结构，火焰中具有明显的局部熄火和再点火区域。在不同来流条件下开展了火焰稳定范围研究，确定了燃烧器的火焰抬升和贫油熄火油气比，燃烧器共呈现了三种不同的燃烧模式:附着火焰、“W”型火焰和“U”型火焰。采用燃气分析仪测量了燃烧器的污染物排放，所有状态下NO_x排放低于10ppm。

Abstract:

Low swirl combustion technology has an ability of ultra-low emissions and is a promising solution to enable lean premixed combustion to meet the low emissions targets for future gas turbine combustors. In order to provide the scientific insights of the key flow features and relevance to flame stability of low swirl combustion， a test rig of vane type low swirl burner associated with different geometric dimensions is developed in the current paper. Particle Image Velocimetry (PIV) is utilized to facilitate the characterization of the flow field associated with swirl number 0.43， 0.49 and 0.55. Then butane is fueled to obtain the stable low swirl flames. The flame features are investigated by means of OH-PLIF diagnostics. Local quenching and relight regions exist in the turbulent flame brush. A series of reacting experiments are conducted under varying inflow conditions and the equivalence ratio corresponding to the flame lift off and blow off are determined. The flame exhibits three different combustion modes including attached flame， ‘W’ shaped flame and bowl shaped flame. The pollutant emissions are identified by the aid of gas analyzer. The emissions of NO_x are less than 10ppm for all conditions.