CAJ | 학술논문

对有凹腔的微细通道内甲烷/空气的预混燃烧进行了实验研究，并与无凹腔的情况进行了比较。结果表明，无凹腔时，只出现了稳定或振荡的倾斜火焰；有凹腔时，在很宽的速度范围内火焰均能被有效地稳定，当进气速度接近吹出极限时，火焰锋面发生弯曲和脉动。当量比为0.8、0.9和1.0时有凹腔的微细通道的吹出极限分别为0.8、1.35和1.75 m·s-1，是对应进气条件下燃烧速度的几倍，这表明凹腔具有很强的稳燃能力。数值模拟结果表明，凹腔的斜壁与下游的水平壁面之间的转折点存在很大的速度梯度和剪应力，导致了火焰在高速下被拉断而吹出。总之，有凹腔的微细通道内火焰的稳定性主要由反应区和流场之间的相互作用决定。
대유요강적미세통도내갑완/공기적예혼연소진행료실험연구，병여무요강적정황진행료비교。결과표명，무요강시，지출현료은정혹진탕적경사화염；유요강시，재흔관적속도범위내화염균능피유효지은정，당진기속도접근취출겁한시，화염봉면발생만곡화맥동。당량비위0.8、0.9화1.0시유요강적미세통도적취출겁한분별위0.8、1.35화1.75 m·s-1，시대응진기조건하연소속도적궤배，저표명요강구유흔강적은연능력。수치모의결과표명，요강적사벽여하유적수평벽면지간적전절점존재흔대적속도제도화전응력，도치료화염재고속하피랍단이취출。총지，유요강적미세통도내화염적은정성주요유반응구화류장지간적상호작용결정。
Premixed CH4/air combustion in a mesoscale channel with cavities were experimentally investigated and compared with that without cavity. The experimental results demonstrate that no symmetric stable flame is observed in the channel without cavities and flame is prone to inclining and pulsating. In contrast, flame can be effectively anchored by the recirculation zone and low velocity zone in the channel with cavities. When the inlet velocity is close to blowout limit, curved fluctuating flames occurs. The blowout limit of the channel with cavities is 0.8, 1.35 and 1.75 m·s-1 for the equivalence ratio of 0.8, 0.9 and 1.0 respectively, which is several times larger than the corresponding burning velocity of incoming CH4/air mixture. These indicate that the cavities have a strong ability to anchor flame. Numerical simulation is performed to help analyzing the flame blowout mechanism, and reasonable accuracy of the numerical model adopted is confirmed. Results reveal that a large shear stress exists at the transition point between the ramped cavity wall and downstream inner wall, making flame split at high inlet velocity, and it is difficult to stabilize the flame in a straight channel. Once the second part of the reaction zone is separated from the one in the cavity, it is prone to blowout. In summary, flame behavior in the mesoscale channel with cavities strongly depends on the interactions between the reaction zone and flow field.