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

Abstract

The suppression mechanisms of carbon dioxide (CO 2 ) as a representative fire suppression agent were revisited using a counterflow diffusion flame which could be applied the concept of a local application system. To end this, the low strain rate CH 4 /air counterflow diffusions with CO 2 addition in either fuel or oxidizer stream were examined numerically using detailed-kinetic chemistry. Radiative heat loss due to radiating gas species including CO 2 added was considered by the optically thin model (OTM). As a result, the critical CO 2 volume fractions in the oxidizer stream required to extinguish the flame were in good agreement with the experimental data reported in the literature, while somewhat under-prediction was observed with CO 2 added in the fuel stream. The surrogate agents were adopted to estimate the quantitative contribution with changing in global strain rate (a g ) on the flame extinguishment among pure dilution effect, thermal effects including radiation heat loss and chemical effect due to the CO 2 fire suppression agent.

Effect of Radiation Models on the Suppression Limits in Counterflow Methane/Air Diffusion Flames

“…이러한 소화과정은 대향류버너 (counterflow burner)를 통해 체계적으로 연구될 수 있다 (1) . 대향류 버너는 유속과 관련된 화염의 신장율(strain rate)을 직접 조절하기 용이하고, 화염면의 위치를 조절하기 편리 한 특성을 가지고 있기 때문에 화염신장율에 따른 소화특 성을 검토하는데 많이 이용되고 있다 (2) .…”