基于释热率分析的钝体贫油熄火过程分析  

Lean blowoff process of bluff body based on heat release rate analysis

作　　者：邢竞文 金捷[1,2,3] 王方 XING Jingwen;JIN Jie;WANG Fang(School of Energy and Power Engineering,Beihang University,Beijing 100083,China;Jiangxi Research Institute of Beihang University,Nanchang 330096,China;Chengdu Innovation Research Institute on Aircraft Power of Beihang University,Chengdu 611930,China)

机构地区：[1]北京航空航天大学能源与动力工程学院,北京100083 [2]北京航空航天大学江西研究院,南昌330096 [3]北京航空航天大学成都航空动力创新研究院,成都611930

出　　处：《北京航空航天大学学报》2022年第3期473-484,共12页Journal of Beijing University of Aeronautics and Astronautics

基　　金：国家自然科学基金(91741125);国家科技重大专项(2017-I-0004-0005,2017-I-0001-0001)。

摘　　要：针对锥形钝体稳定的甲烷-空气预混湍流火焰复杂的熄火过程,采用大涡模拟(LES)与输运方程概率密度函数(TPDF)湍流燃烧模型相结合的模拟方法,研究远离熄火、近熄火及熄火点的火焰和释热率(HRR)数值变化情况,定量分析熄火判据。结果表明:冷态速度模拟结果和实验的相对均方根误差在10%以内,热态误差在20%以内;释热率是否出现在OH和CH;O重叠的区域,是判断熄火的一个重要参数;远离熄火时,释热率高的区域主要沿内侧剪切层出现;近熄火工况下,释热率在流向轴上闭合,回流区下游也出现较大的释热率;熄火点工况下,较大释热率的区域在回流区下游和上游均有出现;模拟预测的熄火情况和实验PLIF结果一致;平均释热率可作为判断熄火的定量依据,即当钝体后方0.2d处内侧剪切层平均释热率与回流区平均释热率的比值小于4时,发生熄火。To understand the complicated blowoff process of premixed turbulence methane-air flame after a conical bluff body,the numerical simulation method based on large eddy simulation(LES)and transport equation probability density function(TPDF)turbulence combustion model was adopted to simulate the flame situations,i.e.far away from blowoff,close to blowoff and blowoff conditions.The flame and the heat release rate(HRR)value under these different conditions were studied,and the criterion for lean blowoff judgement was analyzed quantitatively.The results show that the average relative error between velocity simulation results and experimental results is under 10%in cold situation and under 20%in hot situation.HRR appears in the region where OH and CH;O overlap,and is an important blowoff judgment parameter.When the flame is far away from blowoff conditions,HRR mainly appears at the inner shear layer;when close to blowoff conditions,HRR closes on the flow axis and also appears downstream of the recirculation zone;under blowoff conditions,higher HRR regions spread from downstream to upstream of the recirculation zone.The simulation blowoff predictions are consistent with the experimental PLIF results.In this study,the average HRR can be quantitatively used as a criterion for lean blowoff judgment.At 0.2d section behind the bluff body,blowoff will occur when the ratio of the average HRR for inner shear layer to the average HRR of the recirculation zone is less than 4.

关 键 词：释热率(HRR) 贫油熄火边界预测 大涡模拟(LES) 输运方程概率密度函数(TPDF) 湍流燃烧 

分 类 号：V231.2[航空宇航科学与技术—航空宇航推进理论与工程]