同轴射流非预混火焰闪烁特性及非线性分析  

Flickering Characteristics and Nonlinear Analysis of Non-premixed Coaxial Jet Flames

作　　者：潘文轩 杨茉[1] PAN Wenxuan;YANG Mo(School of Energy and Power Engineering,University of Shanghai for Science and Technology,Shanghai 200093,China)

机构地区：[1]上海理工大学能源与动力工程学院,上海200093

出　　处：《动力工程学报》2020年第7期571-579,共9页Journal of Chinese Society of Power Engineering

基　　金：国家自然科学基金资助项目(51736007,51476103)。

摘　　要：以同轴射流燃烧器为研究对象,对6 mm、11.4 mm和17.4 mm 3种燃烧器直径下的甲烷空气同轴射流扩散火焰进行数值模拟,研究了氧气质量分数在23%~48%内扩散火焰的闪烁特性。结果表明:使火焰稳定的伴流速度比值Ur随着燃烧器直径的增大而增加,3种燃烧器直径下抑制火焰振荡所对应的Ur值分别为0.647、2.2和11.4;作用在火焰面外部的涡旋随着Ur的增大逐渐向火焰下游推移,同时峰值闪烁频率增加,而火焰的振荡幅度逐渐减小,流动与换热特性由周期性振荡转变为混沌状态;火焰的振荡幅度随着氧气质量分数的增加而减小,当氧气质量分数为48%时,火焰的闪烁峰值频率为10 Hz,且火焰闪烁的峰值频率不随氧气质量分数发生变化。Taking the coaxial jet burner as an object of study, numerical simulations were conducted on the coaxial methane-air diffusion flame under the nozzle diameters of 6 mm, 11.4 mm and 17.4 mm, respectively, so as to analyze the flickering characteristics of the diffusion flames with the oxygen concentration in 23%-48%. Results show that the optimum co-flow ratio Ur, under which the flame could be stabilized, increases with rising diameter of the burner, and the corresponding Ur values for the three burner diameters to suppress flame oscillation are 0.647, 2.2 and 11.4 respectively. The vortex surrounding the flame moves downward gradually with the increase of the Ur, when the peak flickering frequency rises, and the amplitude of flame oscillation reduces, while the flow and heat transfer change from periodic oscillation to chaos state. The amplitude of diffusion flame decreases as the oxygen concentration increases, and when the oxygen mass fraction is 48%, the peak frequency is 10 Hz, which does not change with the mass fraction of oxygen.

关 键 词：同轴射流 非预混火焰 氧气质量分数 火焰闪烁 非线性 

分 类 号：TK16[动力工程及工程热物理—热能工程]