SUBADIABATIC AND SUPERADIABATIC PERFORMANCE OF A TWO-SECTION POROUS BURNER
SUBADIABATIC AND SUPERADIABATIC PERFORMANCE OF A TWO-SECTION POROUS BURNER
复制标题
DOI：
10.1080/00102200590950494
复制
发表时间：
2005-07
影响因子：
1.9
通讯作者：
Brian J. Vogel;J. Ellzey
中科院分区：
文献类型：
--
作者：
Brian J. Vogel;J. Ellzey
在多孔介质中，火焰可以在层流火焰速度以上或以下的速度下稳定。这两种状态通常分别称为超绝热和亚绝热。本文对几种燃烧器在超绝热和亚绝热条件下进行了实验研究。给出了稳定燃烧的速度上限和速度下限。对于0.70及以下的当量比，亚绝热和超绝热性能都可以看到。对于亚绝热和超绝热性能，火焰稳定在多孔介质的上游和下游部分之间的界面处或附近。超绝热性能的速度下限是火焰的熄灭。超绝热性能的上限是吹出，这发生在所有的燃烧器在几倍的绝热层流火焰速度的流速，这是由于多孔介质内的热再循环的现象。当当量比大于0.70时，仅观察到亚绝热性能。当火焰达到熄灭时，出现速度下限。当热再循环增强层流火焰速度到火焰前锋通过多孔介质的上游部分传播并在燃烧器的上游闪回的点时，发生速度上限。在当量比为1.1或接近1.1时，速度上限和下限均最小化。对于1.3和1.7之间的当量比和4和9厘米/秒之间的流速，多孔介质的下游部分内的火焰前缘的振荡进行了观察。
ABSTRACT Flames may be stabilized in porous media at velocities either above or below the laminar flame speed. These two regimes are often called superadiabatic and subadiabatic, respectively. In this paper, several burners are investigated experimentally at both superadiabatic and subadiabatic conditions. The upper and lower velocity limits of stable combustion are reported. For equivalence ratios of 0.70 and below, both sub- and superadiabatic performance was seen. For both sub- and superadiabatic performance, the flame was stabilized at or near the interface between the upstream and downstream sections of porous media. The lower velocity limit for superadiabatic performance was extinction of the flame. The upper limit for superadiabatic performance was blowoff, which occurred for all burners at a flow velocity several times the adiabatic laminar flame speed, a phenomenon which is attributed to heat recirculation within the porous media. For equivalence ratios above 0.70, only subadiabatic performance was observed. The lower velocity limit occurred when the flame reached extinction. The upper velocity limit occurred when heat recirculation enhanced the laminar flame speed to a point at which the flame front propagated through the upstream section of porous media and flashed back upstream of the burner. Both the upper and lower velocity limits minimized at or near an equivalence ratio of 1.1. For equivalence ratios between 1.3 and 1.7 and flow velocities between 4 and 9 cm/s, oscillations of the flame front within the downstream section of porous media were observed.