• 대한기계학회논문집B
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• 제22권4호
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• pp.468-480
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• 1998

The temporal and spatial distributions of soot volume fractions were measured for single toluene droplet flames as a function of pressure under the normal-gravity condition. In order to characterize the transient nature of the flame and sooting regions, a full-field light extinction and subsequent tomographic inversion technique was used. The reduction in sooting as a function of pressure was assessed by comparison of the maximum soot volume fractions at several vertical positions along the axis above the droplet. The maximum soot volume fraction was reduced by 70% when the pressure was reduced by 60% from 1 atm to 0.4 atm. The reduction in sooting is attributed to variation of the geometric configuration of flame which reduces the system Grashof number as well as only the change in the adiabatic flame temperature as the pressure decreases. The gravimetrically-measured total soot yield was also compared to the optically-measured soot volume fraction to obtain a correlation between the two measurements. As a result, the total soot yield was linearly proportional to the optically-measured maximum soot volume fraction and linearly reduced as the pressure decreased. Accordingly, the non-intrusive full-field light extinction-measurements were able to be calibrated not only to measure soot volume fraction, but to simultaneously evaluate the total soot yield emitted from the toluene droplet flame (which is useful in the practical application).

• 한국화재소방학회논문지
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• 제33권5호
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• pp.13-18
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• 2019

본 연구에서는 한국형발사체와 유사한 작동환경에서 Jet A1 액체연료의 매연 입자특성에 대해 농도를 측정함으로써 그 결과를 고찰하였다. 발사체환경과 유사한 대기 조건을 모사하기 위해 연소챔버의 산소 농도를 30%로 유지하고 내부 압력을 0.06 MPa에서 0.1 MPa 까지 변화시켜가며 실험을 통해 수행하였고, 대기의 조성을 질소, 헬륨, 이산화탄소 가스로 치환하여 실험을 수행하였다. 직경이 2 mm인 Jet-A1 액적에 동일한 점화에너지를 인가하여 발생 되는 매연 입자의 농도를 전역 광소멸 기법을 이용하여 측정하였다. Jet-A1 액적 화염의 매연 입자입자의 농도는 모든 압력조건에서 대기의 조성이 질소로 치환된 경우 높았으며, 이산화탄소로 치환된 경우 가장 낮았다. 압력이 낮아질수록 매연의 입자농도가 감소하였고, 대기압력의 Pⁿ 형태로 감소하는 경향을 확인하였다.