当量比对不同形状障碍物管道内火焰加速的影响
Effects of Equivalent Ratio on Flame Acceleration in Channels with Obstacles of Different Shapes
董吉舟 1晏自鸿 1李晓曦 1肖华华1
作者信息
- 1. 中国科学技术大学火灾科学国家重点实验室,合肥 230026
- 折叠
摘要
本文采用高速摄像-纹影技术研究了障碍物管道内不同当量比氢/空气预混气体的火焰加速过程.障碍物形状共3种:三角形、全切半圆形以及半圆形.结果表明,当量比通过影响火焰不稳定性和层流燃烧速度,改变了管道内的火焰演化过程以及传播速度.当量比(φ)为1.5时,火焰传播最快.障碍物形状对火焰加速有显著影响.带有尖锐结构的障碍物有利于火焰的拉伸和破碎,促进湍流化.极富燃料工况(φ=3)下,火焰锋面演化更稳定,尖锐的全切半圆形障碍物对火焰锋面湍流化的作用更明显,加速更快.半圆形障碍物管道内火焰过渡平缓,传播最慢.本研究可为燃爆安全防护和燃烧器设计提供实验支持.
Abstract
This paper investigates the flame acceleration process of premixed hydrogen/air with dif-ferent equivalence ratios in obstacle channels by high-speed schlieren photography technique.There are three types of obstacle shapes,including triangle,fully-cut semicircle and semicircle.The results indicate that the equivalence ratio changes the flame propagation speed and evolution process inside the channel by affecting flame instabilities and laminar flame speed.When the equivalence ratio(φ)is 1.5,the flame propagates at the fastest speed.The shape of obstacles has a significant impact on flame acceleration.Obstacles with sharp structures are conductive to the stretching and frag-mentation of flame,promoting flame turbulization.Under extremely rich fuel conditions(φ=3),the evolution of the flame front is more stable,and sharp fully-cut semicircular obstacles have a more significant effect on flame turbulization,enhancing the acceleration.The flame transition in the semicircular obstacle channel is smooth and spreads slowest.This study can provide experimental support for explosion safety and burner design.
关键词
火焰加速/当量比/障碍物形状/氢/空气燃烧Key words
flame acceleration/equivalent ratio/obstacle shape/hydrogen-air combustion引用本文复制引用
基金项目
国家自然科学基金项目(52211530436)
中央高校基本科研业务费专项(WK2320000055)
出版年
2024
NETL
NSTL
万方数据