• Title/Summary/Keyword: Extinguishing concentration

Search Result 18, Processing Time 0.159 seconds

A Study on the Measurement of Flame Extinguishing Concentration of Halon Alternatives by New Test Equipment (할론대체물질의 새로운 불꽃소화농도 측정장치에 관한 연구)

  • 김재덕;임종성;이윤우;이윤용
    • Fire Science and Engineering
    • /
    • v.8 no.1
    • /
    • pp.3-8
    • /
    • 1994
  • A new test system was established to measure the flame extinguishing concentration of Halon alternatives. The main characteristic of this system is to use the solid paraffin with a wick instead of liquid fuel, such as n-Heptane. Our results showed that the extinguishing concentration of compounds was lower than that of other existing data, but the trend was consistent with others. The flame extinguishing concentration of all tested compounds were not almost effected by gas flow velocity. The system produces good reliable data with a minimum error for measuring the flame extinguishing concentration. Therefore our new system can be utilized as a standard equipment to evaluate Halon alternatives.

  • PDF

A Study on the Extinction Concentration of Inert Gas for Extinction Performance Estimation of Kerosene (등유의 소화성능 평가를 위한 불활성 가스의 소화농도에 관한 연구)

  • Choi, Jae-Wook
    • Journal of the Korean Society of Safety
    • /
    • v.22 no.3
    • /
    • pp.34-38
    • /
    • 2007
  • The experiment was done to investigate extinguishing concentrations of different inert gases of verying concentrations made in contact with Kerosene. The experimental results obtained are as follows; at a standard amount of air flow was 40L/min, the extinguishing concentration of Argon, Nitrogen, Carbon dioxide and Helium for Kerosene were 36.5%, 27.3%, 17.4%, 12.3%, respectively. And, according to these results, Helium of 12.3% showed the lowest extinguishing concentration.

Extinguishing Concentration of Inert Gases in Heptane Pool Fires (헵탄 풀화재에서 불활성기체 소화농도)

  • Jung, Tae-Hee;Lee, Eui-Ju
    • Journal of the Korean Society of Safety
    • /
    • v.27 no.3
    • /
    • pp.71-76
    • /
    • 2012
  • The coflow velocity effect on the minimum extinguishing concentration(MEC) was investigated experimentally in heptane cup-burner flames. Various inert gases($N_2$, Ar, $CO_2$, He) were added into the oxidizer to find the critical concentration and the effectiveness of the agents on flame extinction. The experimental results showed that the MECs were increased with increasing coflow velocity for most inert gases except helium, but the higher coflow velocity induced the lower burning rates of heptane. This indicated that the increase of coflow velocity resulted in the decrease of fuel velocity evaporated from fuel surface, and hence the stain rate on the reaction zone was also decreased. In the case of helium as a additive, the extinguishing concentration was independent of the coflow velocity because the heat conductivity was ten times larger than the other inert gases and flow effect by a strain rate might be compensated for heat loss to the surroundings.

Quantitative Difference in the Extinguishing Concentration of Inert Gases with Fire Suppression Criteria in a Cup Burner Test (컵버너시험에서 소화기준에 따른 불활성기체의 소화농도에 대한 정량적 차이)

  • Cho, Jae-Ho;Hwang, Cheol-Hong
    • Fire Science and Engineering
    • /
    • v.28 no.3
    • /
    • pp.34-42
    • /
    • 2014
  • The concentrations of inert gases ($N_2$, Ar, $CO_2$ and He) required to induce the flame instabilities such as swing, rotation, lifted and blow-out were measured in a cup burner nonpremixed flames for $CH_4$ and $C_3H_8$ fuels. Quantitative differences in the extinguishing concentration with fire suppression criteria (i.e. blow-out or onset of flame instability) were also examined. It was found that the difference in extinguishing concentration was increased with the appearance of lifted flame and the low extinguishing performance of inert gaseous. The maximum difference in extinguishing concentration with the suppression criteria was approximately 35% at the highest fuel velocity condition (1.3 cm/s) for the $C_3H_8$-air nonpremixed flame. It can be also expected that the extinguishing concentration by the criteria based on the onset of flame instability will provide the useful information from the viewpoint of the accurate and economical design concentration.

Flame Extinguishing Concentrations of Mixed Gaseous Agents (가스계 혼합소화약제의 불꽃소화농도)

  • 김재덕;임종성;이윤우;이윤용
    • Fire Science and Engineering
    • /
    • v.15 no.1
    • /
    • pp.34-40
    • /
    • 2001
  • Fire extinguishing efficiency of mixed gaseous agents were investigated by the cup-burner test and predicting by the model of flame extinguishing concentration. The binary mixed agents that tested were carbon dioxide/HFC-23, carbon dioxide/HCFC-22, carbon dioxide/HFC-227ea, carbon dioxide/HFC-125, carbon dioxide/FIC-13I1, Hexafluoropropylene/HFC-23 and ternary mixed agents were carbon dioxide/HFC-23/HFC-l34a, carbon dioxide/HFC-23/HFC-227ea, carbon dioxide/HFC-23/HFC-125. A model which contains the flame extinguishing concentration and composition of pure components predicted the flame extinguishing concentration of mixture well. This model was superior when each component of the mixture exhibit physical fire extinguishing performance.

  • PDF

Flame Extinguishing Concentrations and Flue Gas Compositions of n-Heptane by Mixed Inert Gas Agents (불활성 가스계 혼합소화약제의 n-Heptane 불꽃소화농도 및 배가스 조성)

  • 김재덕;김영래;홍승태;이성철
    • Fire Science and Engineering
    • /
    • v.16 no.3
    • /
    • pp.77-83
    • /
    • 2002
  • We measured flame extinguishing concentration and flue gas composition in the n-heptane fuel cup-burner system using inert gas agents such as nitrogen, argon, carbon dioxide and their mixtures. The flame extinguishing concentration of binary gaseous mixture was well predicted by model which contains the flame extinguishing concentration and composition of pure components. The higher average specific gravity of the mixed inert gas agents, the more excellent flame extinguishing performance. And the structure of enclosed space also affects the fire extinguishing. The composition of carbon dioxide in the flue gas was decreased with increasing extinguishing agent used. Nitrogen monoxide production is not related with increasing nitrogen, but increased at rapid mass flow rate of air in the cup-burner.

Effect of Radiation Models on the Suppression Limits in Counterflow Methane/Air Diffusion Flames (대향류 메탄/공기 확산화염에서 복사모델이 소화한계에 미치는 영향)

  • Mun, Sun-Yeo;Cho, Jae-Ho;Hwang, Cheol-Hong;Oh, Chang Bo;Park, Won-Hee
    • Fire Science and Engineering
    • /
    • v.28 no.3
    • /
    • pp.20-28
    • /
    • 2014
  • Effect of radiation models on the suppression limits in counterflow $CH_4$/air diffusion flame was numerically investigated with fundamental experiments for the numerical validation. $N_2$ and $CO_2$ were considered as extinguishing agents. The differences in extinguishing concentration between OTM and SNB radiation models which have different accuracy levels were examined. As a result, there is no considerable difference in extinguishing concentration for the $N_2$ dilution as the radiation models with different accuracy levels were used. As the $CO_2$ having strong radiative effect was diluted in the low strain flames, however, the radiation model with high predictive accuracy such as SNB should be used. In particular, the $CO_2$ dilution in fuel stream leads to the significant difference in extinguishing concentration between OTM and SNB models. Therefore, it is necessary that the radiation model should be reasonably chosen with the consideration of numerical accuracy and computational time for the prediction of extinguishing concentration.

A Study on Extinguishing Concentration of K2CO3-Zeolite Composites (K2CO3가 흡착된 합성제올라이트 구조체의 소화농도에 관한 연구)

  • Kim, Seung-Il;Shin, Chang-Sub
    • Fire Science and Engineering
    • /
    • v.26 no.4
    • /
    • pp.42-47
    • /
    • 2012
  • In the study, fire extinguishing concentration of $K_2CO_3$-Zeolite composite was measured. Zeolite composite is a porous adsorbent which has small particle size, low density and anti-catalytic effect. Scanning Electron Microscopy, X-Ray diffraction and thermal analysis were also conducted to investigate the structural properties of composite. The result showed that despite of weight ratio, the extinguishing concentration of the composite was lower than pure $K_2CO_3$. The extinguishing concentration of $K_2CO_3$-Zeolite composite which has weight ratio of 7 : 3 was 5.72 times lower than that of pure $K_2CO_3$ and 1.1 times lower than that of ABC powder. The SEM and XRD patterns showed that $K_2CO_3$ was adsorbed on the Zeolite properly, and through the thermal analysis, it was founded that the composite is more effective extinguishing agent than pure $K_2CO_3$.

Flame- Extinguishing Concentrations of Inert Gases in Jet Diffusion Flames (제트확산화염에서의 불활성기체 소화농도)

  • Ji, Jung-Hoon;Lee, Eui-Ju
    • Journal of the Korean Society of Safety
    • /
    • v.24 no.1
    • /
    • pp.21-25
    • /
    • 2009
  • Extinguishing limits of laminar ethylene/oxygen flames in both normal and inverse co-flow jet burner have been determined experimentally and computationally. An inert gas($N_2$, Ar, $CO_2$) was added into the oxidizer to find the critical concentration and the effectiveness of the agents on flame extinction. The experimental results showed that the physical aspect of inert gases was main mechanism for flame blow-out as same as cup burner test, but the flow effect should be considered to determine the extinction concentration. The numerical prediction was performed with modified WSR model and the result was in good agreement with the measurements. The experimental and numerical methods could be used for the assessment of various flame suppression agents such as minimum extinguishing concentration.

The Characteristic of Extinguishment of Engine Nacelle Fire Using a Bluff Body (둔각 물체를 이용한 엔진 나셀 화재 소화 특성)

  • Lee, Jung-Ran;Lee, Eui-Ju
    • Journal of the Korean Society of Safety
    • /
    • v.27 no.1
    • /
    • pp.20-25
    • /
    • 2012
  • The purpose of the study is to assess the extinguishing concentration of inert gases in engine nacelle fire. The experiment was performed with a two dimensional rectangular bluff body stabilized flames, where the fuel was ejected to counter flow and co-flow against an oxidizer stream. Two inert gases, $CO_2$ and $N_2$, were used for extinguishing agent in the oxidizer and methane was used for fuel. The main experimental parameters were the direction of injecting fuel, the kinds of agent and the velocity ratio between air and fuel streams, which controlled the mixing characteristic near bluff body and the strength of recirculation zone in the downstream. The result shows the flame structure and the mode were strongly dependent with fuel/air ratio and the fuel jet direction. For both flow configurations, the extinguishing concentration of $CO_2$ was smaller than the $N_2$ because of the large heat capacity of $CO_2$. However, the concentration of inert gasesat blowout was much smaller than those in the cup burner and coflow jet diffusion flames, which implies that the extinction mechanism of bluff body stabilized flames was mainly due to the aerodynamic aspect. Compared to co-flow fuel injection, the extinguishing concentration of inert gases under counter flow configuration was lower. The effect of direction might result from the mixing characteristic and strength of recirculation zonearound a bluff body. More details should be investigated for the characteristic of recirculation zone in the wake of bluff body using the LES(Large Eddy Simulation).