微尺度甲烷扩散火焰及其熄灭特性

用不同直径微/小尺度圆管对甲烷在空气中的扩散燃烧进行实验研究,分析了微/小尺度火焰的结构,考察了影响火焰高度的相关因素,详细探讨了火焰的熄灭极限特点,并拟合了淬熄速度与喷管出口直径d之间的经验关系式.结果表明,火焰的高度与喷管出口速度呈线性关系,随d减小而减小;H/d(火焰高度/喷口直径)与出口处Re值成正比,与d无关;随尺度d的减少,下限(淬熄速度)增大,火焰的稳燃区间变小,稳定燃烧条件苛刻.

Structure and Extinction Characteristics of Methane Micro-Diffusion Flames

The structure and extinction characteristics of methane micro-diffusion flames were investigated in quiescent air with small-size ports with diameter varied from 0.2 mm to 1.0 mm.When the diameter is less than 0.53 mm,the methane micro-diffusion flames were laminar flames;the flame height was linear to the port injected velocity,and at the same port injected velocity,the flame height shortens with smaller port diameter.The scale size effect has no influence on the relationship between the flame height/diameter ratio(H/d) and the port Reynolds number.And the blow-off velocity keeps constant at different diameters,but it influences the quenching limit velocity heavily.The stable flame region reduced as the characteristic size became smaller.