• 한국연소학회:학술대회논문집
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• 한국연소학회 2006년도 제32회 KOSCO SYMPOSIUM 논문집
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• pp.89-95
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• 2006

This study has numerically modelled the combustion processes of the turbulent swirling premixed lifted flames in the low-swirl burner (LSB). In these turbulent swirling premixed flames, the four tangentially-injected air jets induce the turbulent swirling flow which plays the crucial role to stabilize the turbulent lifted flame. In the present approach, the turbulence-chemistry interaction is represented by the level-set based flamelet model. Two-dimensional and three-dimensional computations are made for the various swirl numbers and nozzle length. In terms of the centerline velocity profiles and flame liftoff heights, numerical results are compared with experimental data The three-dimensional approach yields the much better conformity with agreements with measurements without any analytic assumptions on the inlet swirl profiles, compared to the two-dimensional approach. Numerical clearly results indicate that the present level-set based flamelet approach has realistically simulated the structure and stabilization mechanism of the turbulent swirling stoichiometric and lean-premixed lifted flames in the low-swirl burner.

• 대한기계학회논문집B
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• 제30권9호
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• pp.891-897
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• 2006

The SRS method is applied to a turbulent flame with radiation/turbulence interaction to invert the temperature and concentration profile. The flame is conditioned as optically thin per each fluctuation length and the flame spectral intensity is measured for inversion. From inversion result, we find that SRS can successfully invert the coupled temperature/concentration fluctuation amplitudes. For two cases of experiments, inverted values are within approximately 1% over the full range of fluctuation amplitude. However, SRS cannot find the detailed local fluctuation parameters such as pattern and phase, etc. as far as they do not affect the resulting radiation intensity. Important available parameters are the mean temperature and the temperature fluctuation amplitude. The radiation/turbulence interaction effect is verified to play an important role in the radiation.

• 대한가정학회지
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• 제25권1호
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• pp.43-50
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• 1987

Non-durable flame retardant finish, borax/boric acid mixed solution, was applied to cotton fabric with pad-dry method. The LOI(limited oxygen index) was measured as the measare of the flame retardant effect. The TGA was investigated to know the thermal behavior of the samples. In addition, the solubility of the solutions was investigated. The results were as follows: 1) There was a synergism of flame retardant effect in the borax/boric acid mixed solution treatment and the maximum synergism was shown around the ratio of 7 : 3 2) After the borax/boric acid solution treatment, the degradation temperature was lowered and degraded at the larger temp range with slower rate. The residual char length also increased. 3) The solubility of borax/boric acid become higher when the ratio of borax/boric acid became similar. Compositions from 80/20 to 40/60 borax/boric acid mixtures were solubilized well in room temperatuare or warmwater therefor there was no problem for home use.

• 동력기계공학회지
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• 제4권1호
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• pp.39-44
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• 2000

The purpose of this study is to investigate the flame structure and combustion characteristics in the model gas turbine combustor changing equivalence ratio. For this purpose, temperature and ion current were measured and these data were analyzed by the PDF and power spectra technique. We found that the flame length is longer while increasing the equivalence ratio in experimental condition, and especially ${\psi}=0.19$, combustion reaction was active by the stable swirl flow. and these flames were governed by the random three dimensional eddy.

• 한국안전학회지
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• 제25권6호
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• pp.9-13
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• 2010

An experimental study for characteristics of soot were conducted at the post-flame region in jet diffusion flames, where carbon dioxide was used as additives in oxidizer stream. Light-extinction method was performed using He-Ne laser with wave length at 632.8nm for the measurement of relative soot density and soot volume fraction with dimensionless extinction coefficient, $K_e$ and mass specific extinction coefficient, ${\sigma}_s$. To increase of resolution, laser light was modified for sheet-form using concave, convex lenses and slit. C/H ratio was introduced for quantitative analysis of soot growth which is expressed by carbonization and dehydrogen. Also transmission electron microscopy(TEM) was used for observation of morphological shape. The results show that the relative soot density in the post-flame region was lower when carbon dioxide was added in oxidizer stream because of reduction of flame temperature.

• 한국자동차공학회논문집
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• 제11권5호
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• pp.60-69
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• 2003

The simplified two-color method is proposed which can estimate the temperature distribution and the soot density of the whole flame with the image analysis of the high-speed photographs. The factors influenced on its processing were examined, for example, the selection of the wave length, the kind of films, the preparation of the calibration curve between the radiance of flame and the luminance temperature. The simplified two-color method reported in this paper can be used as a tool for the improvement of the combustion process in direct injection diesel engine.

• 한국안전학회지
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• 제10권3호
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• pp.56-61
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• 1995

The behaviors of flame propagation and quenching in a pipe were investigated to make a design criteria of flame arrester. The effects of sealing condition of pipe end, pipe diameter and lengh were studied, and also the effects of thickness of ceramic honycomb monolith on the quenching ability were discussed. Experimental results showed that the flame velocity in case of closed pipe was increased about twenty times faster than that of opened and the sealing coditions of pipe end and length showed significant effects on it. The quenching ability of ceramic honycomb monolith was Increased with thickness and coincided well with Palmer's equation.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2015년도 제51회 KOSCO SYMPOSIUM 초록집
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• pp.123-125
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• 2015

A study has been conducted to investigate the effect of swirl angle in low swirl combustor. In this study, the employed swirl angles were $28^{\circ}$, $32^{\circ}$ and $37^{\circ}$. Direct flame photos show that the width of the flame is expanded and the length of the flame is shortened when swirl angle is increased. Also, as the swirl angle was increased, the flame stability region could be widened due to the expansion of lower flammable limit. Between 3 and 7kW, CO emissions was below 10 ppm and NOx emissions was also below 27 ppm at $O_2$ 15% basis over the lean burning range of 0.6 < ${\Phi}$ < 0.9. From this investigation of stability expansion effect and emission performance, it was identified that the swirl angle $37^{\circ}$ is most suitable swirling condition in the low swirl model combustor.

• 대한기계학회논문집B
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• 제34권2호
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• pp.197-202
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• 2010

자발 진동하는 층류 예혼합 분젠 화염을 관찰하기 위하여 분기관을 가진 연소기를 제작 하였다. 특히, 조건에 따른 화염 거동을 살펴봤으며, 화염 표면적과 열발생 변동의 관계에 대하여 고찰하였다. 본 연구에서 사용된 당량비는 1.1 이고, 노즐 출구 평균 유속은 1.75 m/sec 이다. 연소 챔버와 분기관의 길이비(L.R.)는 연소기 내 압력 변동에 영향을 미치며, 결과적으로 화염 거동 특성이 달라짐을 관찰하였다. 또한, 간섭 필터의 유무에 따른 $OH^*$, $CH^*$, 그리고 화염 자발광은 정성적으로 유사한 거동을 나타냈으며, 자발 진동하는 층류 예혼합 분젠 화염의 화염 표면적 변동과 열발생 변동은 선형적인 관계를 가짐을 확인하였다.

• 폴리머
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• 제26권2호
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• pp.200-208
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• 2002

난연성분인 트리클로로벤조산(TBA)의 함량을 10, 20, 30 wt%로 변화시키면서 아디프산, 1,4-부탄디올 및 트리메틸올프로판과 축중합을 하여 트리클로로 락톤 변성폴리에스테르(TAPTs)를 합성한 후에, TAPT류와 이소시아네이트인 Desmodur IL을 블렌드하여 2성분계 폴리우레탄 난연 도료를 제조하였다. 제조된 난연도료의 도막물성을 측정한 결과, 결코 비난연도료보다 물성이 떨어지지 않음을 알았다. 또한 난연도료의 3종류 난연성 시험결과, 수직법에서 TBA 함량 20 wt% 이상에서 불꽃에 타지 않았고, LOI 연소성 시험에서 TBA 함량 20, 30 wt%시 25%와 27%의 LOI값을 나타내었으며, $45^{\circ}$ Meckel burner법에서는 탄화길이가 3.6-5.2 cm로서 난연 1급에 해당되었으므로 이를 미루어 난연효과가 좋은 난연도료임을 알 수 있었다.