气流入口条件对低旋流燃烧火焰稳定性的影响  

Effects of Inlet Conditions on Low Swirl Combustion Flame Stability

作　　者：陈立[1] 李祥晟[1] 杨诏 卢炼[1] 

机构地区：[1]西安交通大学能源与动力工程学院,西安710049

出　　处：《西安交通大学学报》2016年第5期114-119,共6页Journal of Xi'an Jiaotong University

摘　　要：为了研究低旋流燃烧器在喷嘴出口气流平均速度为10.12~19.12m/s、入口温度为300~500K、入口压力为101.325~8×101.325kPa条件下的火焰稳定性,对当量比为0.7的甲烷空气预混气体进行了数值模拟,分析了低旋流燃烧器的流场结构及火焰特性,揭示了燃烧稳定的根本原因。结果表明：低旋流燃烧器流场结构受气流入口条件的影响较小,且能够保持自相似特性;轴向和径向速度延伸率以及虚拟原点的位置基本不受气流入口条件的影响;低旋流燃烧器流场随喷嘴出口气流平均速度、入口压力的增加,回火的可能性减小,随入口温度的提高,回火的可能性增大。综合而言,低旋流燃烧器能够在较宽气流入口条件下保持火焰锋面稳定,有利于燃烧器的稳定工作。A numerical simulation of premixed methane-air gas at equivalence ratio 0.7 was conducted to investigate the flame stability of the low swirl combustion under the conditions of different bulk velocity from 10.12m/s to 40.00m/s,inlet temperature from 300 Kto 500Kand inlet pressure from 101.325 kPa to 8×101.325 kPa.Mechanism of the combustion stability was revealed by analysis of flow field structure and flame characteristics of the low swirl injector.The results show that the bulk velocity,inlet temperature and inlet pressure exert small influences on the flow field structure,so the self-similar characteristics of the low swirl combustion remain.The mean axial aerodynamic stretch rate,the mean radial aerodynamic stretch rate and the virtual origin are almost not affected by the inlet conditions,which facilitates protecting the stability of flame front.The possibility of backfiring reduces with the increasing bulk velocity or the inlet pressure,while the possibility of backfiring increases with the increasing inlet temperature.The flame front of low swirl combustion retains its stability under wider inlet conditions.

关 键 词：低旋流燃烧 自相似特性 火焰锋面 回火 

分 类 号：TK47[动力工程及工程热物理—动力机械及工程]