摘要
为了研究垂直圆管内掺氢甲烷燃烧的不稳定性,自行搭建了上端为开口下端为闭口的透明圆形燃烧管道(半径r=30 mm,管长L=600 mm),火焰在开口端被点燃,向闭口端传播,在化学当量比条件下,通过改变氢气体积分数进行实验。结果表明,当氢气体积分数γ≥50%后,火焰在传播过程中出现了数量众多的小尺寸胞状结构,并逐渐演变为平滑的弯曲火焰锋面结构,而在γ<50%的工况中没有出现此现象;对初级不稳定性振荡以及次级不稳定性振荡出现的原因进行了分析,火焰表面积的快速变化是形成初级不稳定性振荡的主要原因,燃烧过程中产生的有限振幅的声学振荡是次级不稳定性振荡产生的原因;对不同工况反应过程组分流量的敏感性分析可以得出,链式反应R1(H+O_(2)=====O+OH)为促进燃烧反应速率的主导链式反应;火焰传播过程中的最大压力出现在次级不稳定性振荡阶段,由于开口声压损失以及开口预混未燃气体损失,最大压力的数值随氢气体积分数的增加而减小。
In order to study the instability of hydrogen-doped methane combustion in vertical circular tube,a transparent circular combustion tube(radius r=30 mm,tube length L=600 mm)with upper end opening and lower end closing was built.The flame was ignited at the opening end and propagated to the closing end.Under the condition of chemical equivalence ratio,the experiment was carried out by changing the volume fraction of hydrogen.The results show that when the volume fraction of hydrogenγ≥50%,a large number of small-size cellular structures appear in the flame propagation process,and gradually evolve into the flame front structure of the approximate plane,but this phenomenon does not appear in the case ofγ<50%.The primary unstable oscillation and the causes of the secondary unstable oscillation are analyzed.The rapid change of flame surface area is the main reason for the formation of primary instability oscillation,and the limited amplitude acoustic oscillation produced in the combustion process is the reason for the secondary instability oscillation.The sensitivity analysis of the component flow rate of the reaction process under different operating conditions can be concluded that the chain reaction R1(H+O_(2)=====O+OH)is the dominant reaction to promote the combustion reaction rate.The maximum pressure in the flame propagation process appears in the secondary instability oscillation stage.Due to the opening sound pressure loss and the opening premixed gas loss,the maximum pressure value decreases with the increase of hydrogen volume fraction.
作者
吴一
温小萍
张素梅
郭志东
邓浩鑫
纪文涛
WU Yi;WEN Xiaoping;ZHANG Sumei;GUO Zhidong;DENG Haoxin;JI Wentao(School of Mechanical and Power Engineering,Henan Polytechnic University,Jiaozuo 454003,Henan,China;State Key Laboratory of Coal Mine Disaster Dynamics and Control,Chongqing University,Chongqing 400044,China;School of Safety Science and Engineering,Henan Polytechnic University,Jiaozuo 454003,Henan,China)
出处
《化工学报》
EI
CSCD
北大核心
2022年第10期4780-4790,共11页
CIESC Journal
基金
国家自然科学基金项目(51774115,52004085)。
关键词
氢气
甲烷
不稳定性
火焰结构
敏感性分析
hydrogen
methane
instability
flame structure
sensitivity analysis
