• Journal of Energy Engineering
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• v.24 no.1
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• pp.132-136
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• 2015

The objective of this study is to investigate the effect of biodiesel blending on spray and combustion characteristics. In order to this, blended fuels containing 0, 5, 20, 50, 100% biodiesel in weight fraction was injected via common rail to constant volume combustion chamber. As a result, spray cone angle decreased and the Sauter mean diameter increased because of the higher dynamic viscosity and density of biodiesel, however, it does not seemed that spray penetration was affected by these factors considerably. In the combustion experiment, ignition delay of biodiesel was shorter than that of diesel due to higher cetane number. And the peak value of heat release rate increased and the end of combustion was advanced owing to higher combustion efficiency cause by the characteristic of oxygenated fuel.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.5
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• pp.315-321
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• 2004

To compare soil carbon contents by Tyurin method and dry combustion method, we carried out analysis for 212 samples of agricultural land in Korea. The average values of soil carbon contents analyzed by Tyurin method and dry combustion method were $17.47{\pm}10.80$ and $19.91{\pm}10.63g\;kg^{-1}$, respectively. Both methods were evaluated as acceptable methods for soil carbon contents as the results showed. The results showed that soil texture had little effect on analysis method of carbon contents. Highly significant linear regression equation, Y = 0.846X ($R^2=0.991$), was obtained between carbon contents analyzed by Tyurin method (Y) and dry combustion method (X). As a result of comparison with data of carbon contents of the two methods, about 69% of results at dry combustion method have exceeded to results at Tyurin method. Especially, differences between results at two methods became higher as carbon contents were increasing. Tyurin method has been advantages such as shorter analysis time for one sample, more recognition for carbon analysis, and no need for expensive analyzer, while dry combustion method has simpler procedure, no heavy metal wastes, and more samples for analysis at one time.

• Journal of Energy Engineering
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• v.8 no.1
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• pp.159-165
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• 1999

복합화력 발전플랜트의 운전에서 특히 하절기의 첨두부하시에 외기온도의 상승으로 인한 가스터빈의 출력 감소를 해결하기 위한 방법으로 LNG 연료가 보유하고 있는 냉열을 이용하여 압축기로 유입되는 공기 온도를 감소시키는 냉각시스템의 개념을 개발하고자 복합화력 발전플랜트에 대한 설계점 및 외기온도 변화에 대한 탈설계점 모델링 연구를 수행하였다. 대상 프랜트는 940 MW 서인천 복합 발전플랜트 모듈의 단위 블록을 선택하였으며 발전플랜트 전용 해석코드인 GateCycle을 이용하여 가스터빈과 증기사이클의 주요 기기 들에 대한 모델을 개발하였다. 개발된 모델의 결과를 대상플랜트의 시운전결과와 비교하여 모델의 적정성을 검증하였다. 출력, 효율, 온도 및 유량 등 주요 설계인자들이 최대 ~1.3%의 상대오차 범위 안에서 만족할 만한 신뢰도를 갖는 것을 확인하였다. 탈설계점 성능해석은 본 논문과 관련한 연구의 주목적인 LNG 냉열에 의한 유입공기 냉각시스템 설계시의 경계변수인 외기온도 증가에 대한 각 사이클의 특성변화를 대상으로 하였다. 종합적으로 외기온도가 증가하면 압축기로 유입되는 공기의 양과 이에 대응하는 소요 연료량이 동시에 감소하므로 연소에 따른 가스터빈의 팽창비가 감소한다. 이로 인하여 외기온도 증가시에 가스터빈 출력감소율은 0.5%/$^{\circ}C$로서 배기가스를 이용하는 증기사이클의 출력감소율 0.2%/$^{\circ}C$에 비해 민감하므로 가스터빈 유입공기의 냉각시스템의 설계는 복합화력발전 플랜트의 효율 향상에 크게 기여할 것으로 예상된다.

• Journal of the Korean Institute of Gas
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• v.24 no.5
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• pp.29-38
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• 2020

It is practically difficult to accurately measure the temperature and concentration of a large combustion systems at industrial sites in real time. Temperature measurement using thermocouple, which are mainly used, is a point-measuring method that is less accurate and less reliable to analyze the wide area range of inner combustion system, and has limitations to internal accessibility. In terms of concentration analysis, most measurement methods use sampling method, which are limited by the difficulty of real-time measurement. As a way to overcome these limitations, laser-based measurement methods have been developed continuously. Laser-based measurement are line-average measurement methods with high representation and precision, which are beneficial for the application of large combustion systems. In this study the temperature and concentration were measured in real time by water vapor and oxygen generated during combustion using Tunable Diode Laser Absorption Spectroscopy (TDLAS). The results showed that the average temperature inside the combustion system was 1330℃ and the mean oxygen concentration was 3.3 %, which showed similar tendency with plant monitoring data.

• Explosives and Blasting
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• v.33 no.3
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• pp.21-28
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• 2015

The objective of this study is to develop a method for monitoring continuously the combustion propagation behavior of commercial thermite reaction mixtures using conventional continuous VOD (velocity of detonation) system. In order to monitor the combustion front propagation with elapsed time during thermite reaction, the VOD system employs two types of commercial VOD probes and one self-made probe: VOD PROBEROD-OS, VOD PROBEROD-HS and VOD PROBEROD-ES, respectively. Among the probes, the only self made VOD PROBEROD-ES successfully demonstrates the velocity of combustion propagation (VOC) with elapsed time. It was found that VOC of the thermite reaction mixture inside a steel tube has been reached around 200m/s within 100mm distance from the ignition and dramatically increased up to about twice the speed of sound in the range between 100mm and 300mm distance. Finally the VOC reached up to around 800m/s. This results imply that it is necessary to use over 300mm long cartridge of thermite reaction mixture in order to achieve normal VOC of the mixture.

• Fire Science and Engineering
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• v.27 no.5
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• pp.19-25
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• 2013

The fire took place in the synthetic heat transfer fluid boiler. This study uses simulation to investigate the first, second and third passes and the temperature in the fire burner. The boiler's internal fluid is more or less unsteady due to the out of order inverter. As the operation continues, the flame's flow and speed are unsteady. The synthetic heat transfer fluid leak spouted about 120 kg/min in the form of vapor in the early period of the fire. The flame extended to the second and third passes. The highest temperature of the second and third pass is $1059^{\circ}C$ and $1007^{\circ}C$, respectively. The simulation shows that the temperature is $767^{\circ}C$ in the low part of the third pass. The synthetic heat transfer fluid spouted through the cracked part of the fire box in the first pass and accumulated on the turn table. The temperature rises to $183^{\circ}C$ in the low part of the burner. Therefore, it is expected that the temperature of the interior of the fire box is above $1200^{\circ}C$. The temperature of the burner rises to a maximum level several times in a short period. On account of that, several explosions occur in the fire burner.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.3
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• pp.259-267
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• 2010

In this study, the effect of particle size on the combustion characteristics of pulverized sub-bituminous coal was experimentally investigated. A laminar-flow-entrained reactor was designed and implemented to realize the desired heating ratio and temperature corresponding to the combustion atmosphere of a pulverized-coal-fueled furnace. The flame length and structure of burning particles according to different sizes were investigated. Coal combustion processes were clearly distinguished by direct visual observation of the flame structure. The onset point of volatile ignition is greatly affected by changes in the particle size, and the burning time of the volatiles is least affected by changes in the particle size. The length and instability of char flame also increase with the increase of the particle size. However, the char consumption rate within the residential time remains nearly constant.

• Proceedings of the Optical Society of Korea Conference
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• 2002.07a
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• pp.236-237
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• 2002

원자력 발전소에서 사용되는 연료의 효율을 증가시키기 위해서는 반응로에서 연소된 연료에 잔존하는 미량의 란탄족 (lanthanide)과 악티늄족 (actinide) 원소를 측정하고, 동위원소 성분비를 분석하는 작업이 필요하다. 이러한 미량원소 측정에는 흡수분광학 (absorption spectroscopy) 방법이 주로 사용되고 있다. 최근 들어 단일 종 모드 (single-longitudinal mode) 반도체 레이저가 개발되면서 미량원소 분석을 위한 분광 기술이 급속히 발전하고 있다. 반도체 레이저는 동작시킬 때 전력소모가 적고, 설치 공간이 작다는 점 때문에 현장 적용이 용이하므로 미량원소 측정 연구의 광원으로 많이 활용되고 있다. (중략)

• Journal of Energy Engineering
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• v.4 no.3
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• pp.324-330
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• 1995

석탄 연소로에 사용 적합한 석탄의 선정 및 조업조건의 설정에 도움을 주고, 석탁회분의 슬래깅 성향을 파악하기 위해서 갈탄부터 역청탄에 이르는 4종의 시료를 사용하여 산화성 분위기에서 고온 회전 점도계를 사용하여 석탄회분 슬래그의 점도를 온도의 함수로서 측정하였다. 또한 석탄회분의 슬래깅 성향을 해석하기 위해서, 석탄회분 조성을 사용한 Base/Acid Ratio, Lignite Factor 및 Silica Ratio 등의 주요한 인자들이 슬래그 점도에 미치는 영향을 고찰하였다.

• Journal of the KSME
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• v.32 no.12
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• pp.1049-1058
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• 1992

자동차 공해를 저감하기 위해서는 정부 당국의 도로 여건 개선을 통한 교통 체증의 해소, 자동차 제조기술(연소, 제어, 배기가스 정화등)의 개선, 정유사의 저공해 연료 개발 및 운전자 개개인의 운전 습관 개선, 차량 정비 점검 등 제반 노력이 합치되어야 할 것이다. 이중 연료 측면에서의 대기오염 개선을 위한 저공해화 기술을 요약하면 다음과 같다. 자동차 배기가스에 영향을 미치는 휘발유의 황함량을 낮추면 휘발유 자동차의 유해 배기가스 배출이 전반적으로 감소한다. RVP와 방향족 함량은 낮을수록, 함산소화합물함량은 높을수록 HC와 CO를 저감시키며 특히 CO의 저 감이 현저하다. 90% 증류점을 낮추면 HC 배출량이 크게 감소하고 올레핀함량을 낮추면 $NO_{x$ 배출이 억제된다.