超声场中正庚烷液滴火焰抬升机制  

Lifted-Off Flame Mechanism of n-Heptane Droplet Combustion in Ultrasonic Field

作　　者：龙相州 苟小龙[1] Long Xiangzhou;Gou Xiaolong(School of Energy and Power Engineering,Chongqing University,Chongqing 400044,China)

机构地区：[1]重庆大学能源与动力工程学院,重庆400044

出　　处：《燃烧科学与技术》2020年第6期558-566,共9页Journal of Combustion Science and Technology

基　　金：国家自然科学基金资助项目(51776023).

摘　　要：为了揭示超声对液体燃料燃烧的影响机制,采用高速摄影仪、纹影仪和激光诱导荧光(PLIF)等测试手段对超声场中液滴燃烧过程的相关参数进行了测量.并结合有限元模拟软件COMSOL MULTIPHYSICS,分析了正庚烷液滴在超声作用下的自由基分布以及蒸发燃烧特性.结果表明,超声对火焰形状、燃烧速率以及自由基分布有着显著的影响,其中超声声辐射力促进流动与蒸发是影响液滴燃烧的重要因素之一,超声通过改变蒸气的聚集形态进而影响火焰.进一步研究发现,超声对液滴燃烧特性的影响与声场的分布直接相关,且波节与波腹对液滴燃烧的促进与抑制效果明显不同.本研究在一定程度上揭示了超声波影响液体燃料燃烧的机制,证实了超声波在稳燃以及燃烧调控方面的可行性.To reveal the mechanism of ultrasonic effect on the liquid fuel combustion,some testing methods such as the high-speed camera,Schlieren and planar laser induced fluorescence(PLIF)were used to measure related parameters during the droplet combustion process in ultrasonic field.The free radical distribution and combustion characteristics of n-heptane droplet were analyzed with the combination of simulation results obtained using the finite element software COMSOL and experimental data.Results show that ultrasonic had obvious effects on the flame shape,combustion rate constant and the distribution of free radicals.In particular,the flow and evaporation promoted by ultrasonic radiation was one of the important factors that affect the droplet combustion.Besides,the aggregation morphology of vapor which had a great influence on droplet combustion was affected by ultrasonic.Further studies show that the ultrasonic impact on droplet combustion characteristics was directly related to the distribution of sound field,and the promotion and inhibition effects of nodes and antinodes of ultrasonic on the droplet combustion were significantly different.This study revealed the mechanism of ultrasonic liquid fuel combustion to some extent and confirmed the feasibility of ultrasound in improving the combustion stability and combustion control.

关 键 词：超声辐射 燃烧速率 液滴 正庚烷 

分 类 号：TK428.9[动力工程及工程热物理—动力机械及工程]