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开发了一种微型钝体燃烧器,实验和模拟均表明钝体能使吹熄极限扩大5倍以上.采用氢气/空气的详细反应机理,通过数值模拟研究了钝体的尺寸大小,即阻塞比(ζ)对火焰吹熄极限的影响.结果表明:当ζ分别为0.3,0.4和0.5时,吹熄极限分别为20,32和36m/s,即吹熄极限随着阻塞比的增大而增大;当ζ=0.3时,钝体后的回流区太小导致火焰在较小的进气速度下即被整体吹出燃烧室,而对于ζ=0.4和0.5的情况,火焰由于在高速下受到剪切层的强烈拉伸作用而导致熄灭,实验观察也证实了这一现象;由于反应区集中于燃烧室中央,高温气体对壁面的作用减弱,使得不同阻塞比的钝体燃烧器之间的散热损失差别不大.
A micro-bluff body burner was developed, both experimentally and simulatively showed that the bluff body can make the blow-out blow-out limit more than 5 times.Using the detailed reaction mechanism of hydrogen / air, the size of the bluff body was studied by numerical simulation, ζ) on the blow-out limit of the flame.The results show that when the ζ are 0.3, 0.4 and 0.5 respectively, the blow-out quenching limits are 20, 32 and 36 m / s, respectively, that is the blow-out limit increases with the increase of the blockage ratio At ζ = 0.3, the backflow zone behind the bluff body is too small to cause the flame to be blown out of the combustion chamber at a relatively small intake air velocity, whereas for ζ = 0.4 and 0.5, the flame is subjected to shear at high speed This phenomenon is also confirmed by experimental observation. As the reaction zone is concentrated in the center of the combustion chamber, the effect of the high-temperature gas on the wall surface is weakened, so that the heat dissipation between the bluff body burners with different blocking ratios Little difference between losses.