小尺度湍流对近极限非预混火焰熄灭极限的影响  

Effect of Small-Scale Turbulence on Extinction Limit of Near-Limit Non-Premixed Flames

作　　者：邹俊 杨协和 张扬[1] 吴玉新[1] 张海[1] 吕俊复[1] Zou Jun;Yang Xiehe;Zhang Yang;Wu Yuxin;Zhang Hai;LüJunfu(Key Laboratory for Thermal Science and Power Engineering of Ministry of Education,Department of Energy and Power Engineering,Tsinghua University,Beijing 100084,China)

机构地区：[1]清华大学能源与动力工程系热科学与动力工程教育部重点实验室,北京100084

出　　处：《燃烧科学与技术》2022年第2期190-197,共8页Journal of Combustion Science and Technology

基　　金：国家自然科学基金资助项目(51706119);四川省科技计划资助项目(2018JZ0021,2019YFS0497).

摘　　要：基于“比拟理论(analogy theory)”,本文研究了小尺度湍流引发的传热传质增强作用对湍流非预混火焰熄灭极限的影响.结果表明:小尺度涡的传热传质增强作用使湍流非预混火焰层厚度增厚,火焰温度降低,火焰层内活性自由基H和OH的摩尔分数降低.化学反应时间和停留时间都随湍流强度增加而增加;但在同一湍流强度下,不同燃料浓度的非预混火焰熄灭临界达姆克勒数(Damköhler number)近似为定值,该临界达姆克勒数随着湍流脉动速度的增加而增加.The effect of heat and mass transfer enhancement induced by small-scale turbulence on the extinction limit of turbulent non-premixed flames was studied using the“Analogy theory”.The results show that the heat and mass transfer enhancement induced by small-scale vortex leads to the thickening of turbulent non-premixed flame layer,the decrease of flame temperature,and the reduction of mole fraction of active H and OH radicals in the flame layer.The chemical reaction time and residence time increase as the turbulence intensity increases.In addition,the critical Damköhler number of non-premixed flames with different fuel concentrations is approximately a constant at the same turbulence intensity.However,the critical Damköhler number increases with the increase of turbulent fluctuating velocity.

关 键 词：小尺度湍流 小火焰 扩散火焰 熄灭极限 传热传质 

分 类 号：TK16[动力工程及工程热物理—热能工程]