산소부화와 희석제에 따른 비예혼합 화염의 안정성

Abstract

CO₂ is well known greenhouse gas which is the major source of global wanning. Reducing CO₂ emission in combustion process can be achieved by increasing combustion efficiency, oxygen enriched combustion and recirculation of the emitted CO₂ gas. Stability of non-premixed flame in oxygen enriched environment will be affected by the amount of oxygen, kind of diluents and fuel exit velocity. The effects of these parameters on flame liftoff and blowout are studied experimentally in oxidizer co flowing burner. Experiments were divided into three cases according as where CO₂ gas was supplied. - 1) to coflowing air, 2) to fuel with O₂-N₂ co flow, 3) to co flowing oxygen. Flame in air coflowing case was lifted in turbulent region. Flame lift and blowout in laminar region with the increase in CO₂ volume fraction in CO₂-Air mixture makes flame lift and blowout in laminar region. Increase in oxygen volume fraction makes flame stable-i.e. flame liftoff and blowout occur at higher fuel flowrates. Liftoff height was non-linear function of nozzle exit velocity and affected by the O₂ volume fraction. It was found that the flame in O₂-N₂ coflow case was more stable than O₂-CO₂ case. Liftoff heights vs (nozzle exit velocity/laminar burning velocity)^3.8 has a good correlation in O₂-CO₂ oxidizer case.br/