摘要
基于平面激光诱导荧光(PLIF)技术,在常温常压下对富燃料正丁烷/空气同轴射流预混火焰结构及热释放率(HRR)特性进行了实验研究。通过火焰轴截面的OH-PLIF与CH_(2)O-PLIF二维测量以及[OH]×[CH_(2)O]归一化乘积获得热释放率分布特性,计算得到火焰面厚度值,并与火焰自发光CH*自由基表征的热释放率分布与火焰厚度值进行比较。结果表明:火焰中热释放率区域位于CH_(2)O与OH自由基峰值之间,基于PLIF测量得到的热释放率区间比CH*自发光区域稍小;燃料当量比对热释放率峰值位置和分布区域有较大的影响,但低雷诺数下预混气初始流速对热释放率分布的影响较小;根据OH自由基与CH_(2)O峰值位置间距得到的火焰面厚度值明显大于利用CH*自发光和[OH]×[CH_(2)O]得到热释放率的半峰全宽。
Objective Planar laser-induced fluorescence(PLIF)technology is commonly used for flame structure diagnosis.For instance,OH hydroxyl(OH radical)and formaldehyde(CH_(2)O)groups in different flames have been extensively measured using the PLIF technology.Generally,the OH radical and CH_(2)O mainly exist in high-and low-temperature oxidation zones of carbon fuel flames,respectively.The heat release rate(HRR)of flames can also be measured indirectly by calculating[OH]×[CH_(2)O]after obtaining the OH-PLIF and CH_(2)O-PLIF images.However,most previous studies have focused on the HRR distribution measurement in turbulent flames with light fuels(e.g.,methane)based on the PLIF technology and the measurement of flame thickness has received limited attention.In this study,the PLIF technology is used to measure the HRR and flame thickness of n-butane/air laminar flames under varied equivalence ratios and inlet flow velocities.Moreover,the obtained results are compared with those based on CH*chemiluminescence imaging.Because the oxidation reaction process of n-butane is similar to that of some large molecular hydrocarbon fuels,the findings of this study can provide quantitatively experimental data for further understanding the combustion characteristics of n-butane and large molecular hydrocarbon fuels.Methods In the experiment,a coflow burner is used to generate n-butane/air jet flames for optical diagnosis.The inner diameter of the burner center tube for supplying n-butane/air mixtures is 4.5 mm,and the diameter of the sintered bronze plug plate of the burner for supplying the accompanying air is 60 mm.The equivalence ratios of the mixtures are 1.1-1.5.The mixture flow velocity is varied from 1.6 to 2.0 m/s with the Reynolds number Re=497-636.The PLIF technology(LaVision Inc.)is employed to measure the flame structure.The OH-PLIF and CH_(2)O-PLIF measurements are performed using excitation wavelengths near 283 and 355 nm,respectively(~6.5 and 260 mJ/pulse,respectively,@10 Hz).All fluorescence signals are measured using an I
作者
金川
蒋利桥
李凡
李星
汪小憨
Jin Chuan;Jiang Liqiao;Li Fan;Li Xing;Wang Xiaohan(Guangzhou Institute of Energy Conversion,Chinese Academy of Sciences,Guangzhou 510640,Guangdong,China;Nano Science and Technology Institute,University of Science and Technology of China,Suzhou 215123,Jiangsu,China)
出处
《中国激光》
EI
CAS
CSCD
北大核心
2022年第13期51-59,共9页
Chinese Journal of Lasers
基金
国家重点研发计划政府间国际科技创新合作重点专项(2016YFE0127500)
广东省科技计划项目(2016A040403095)。
关键词
测量
平面激光诱导荧光
热释放率
火焰面厚度
射流预混火焰
正丁烷
measurement
planar laser induced fluorescence
heat release rate
flame thickness
jet premixed flame
n-butane
