The influence of carbon dioxide and oxygen as additives on soot formation in diffusion flames

Experimental assessment of the sudden-reversal of the oxygen dilution effect on soot production in coflow ethylene flames

“…Still, the latter does not incorporate the uncertainty associated with E(m) due to the ongoing debate about this quantity in the combustion community. allows the sooting tendency to be reversed as mentioned earlier for air as the coflow oxidizer [7,14,15]. For X ax O 2 higher than 32%, the flame burning in the air coflow starts experiencing flickering, an instability that is intimately linked to soot load at the flame tip [21,29].…”

“…As discussed by Du et al [7] and Liu et al [8], the reduction of soot formation resulting from the introduction of inert gaseous additives, such as N 2 or Ar, can be attributed to two main effects: 1 a dilution effect because of the reduction in the concentrations of the reactive species; 2 a thermal effect due to the change in flame temperature as a consequence of the streams' physical properties variation.…”

“…For the purpose of studying the effect of adding oxygen to the fuel stream of a laminar coflow diffusion flame, methane, ethylene, and propane have commonly been used as the fuel and different soot formation behaviors were reported [7,9,[14][15][16][17][18]. Gülder et al [9] investigated the effects of adding oxygen and nitrogen to three fuels (methane, propane, and n-butane).…”

“…The authors explained that the unique sooting behavior exhibited by methane is due to the reduction in acetylene concentration among the pyrolysis products as the oxygen mole fraction in the methane stream is increased. Interestingly, addition of oxygen to fuel in ethylene diffusion flames exhibits the features of these opposite trends: soot formation is first significantly promoted when increasing the oxygen mole fraction in the fuel stream, then soot formation 6 is abruptly reduced above a critical oxygen mole fraction of approximately 32% [7,14,15]. Different explanations of this sudden trend reversal were proposed.…”

A Numerical Study on the Extinguishing Effects of CO2in Counterflow Diffusion Flames with the Concept of Local Application System

“…이들 CO 2 의 소화효 과는 본질적으로 분리되어 설명될 수 없으나, 최근 상세 반응기구를 이용한 수치해석의 적용을 통해 연료 및 공기 류에 첨가된 CO 2 의 복사 열손실 및 화학반응의 참여 유무 에 따른 화염구조, 소염, NOx 및 soot 생성특성 차이에 관 한 많은 연구들이 진행되고 있다 (2,(8)(9)(10) . Figure 1과 같은 대향류 확산화 염을 대상으로 하였다.…”