• 한국연소학회:학술대회논문집
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• 한국연소학회 2014년도 제49회 KOSCO SYMPOSIUM 초록집
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• pp.339-342
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• 2014

Rotary kiln produces lime from limestone through thermal decomposition. Ring formation in kiln internal wall is known issue that decreases productivity. The cause of ring formation is temperature imbalance as flame leans toward upper wall. Therefore, burner nozzle geometry was changed to improve air-fuel mixing state which leads to prevention of ring formation. CFD simulation and experimental test were performed in this study to investigate the effect of air-fuel mixing on flame structure, temperature and $NO_X$ concentration. It is shown that combustion efficiency has been enhanced and $NO_X$ concentration has been decreased by using swirl flow for secondary combustion air. It's also shown that flame has been straightened by using straight flow for secondary combustion air.

• 보존과학회지
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• 제35권5호
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• pp.470-479
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• 2019

본고에서는 백제금동대향로의 고화질 촬영 및 실측을 통해 배연공과 흡기공의 확장이유를 밝히고자 하였다. 실험을 위해 백제금동대향로를 3차원 정밀 스캔한 뒤 스캔한 원본데이터를 기반으로 백제금동대향로 정밀재현품과 시판복제품을 3차원 스캔하여 전체적인 형태와 세부적인 문양을 원본데이터와 비교하였고, 뚜껑 내부구조 및 향연구멍의 크기와 위치가 실제유물과 가장 유사한 정밀재현품을 이용하여 배연공과 흡기공의 크기와 개폐유무에 따라 분향실험을 진행하였다. 분향실험 결과, 배연공과 흡기공의 크기에 따라서는 아랫줄 흡기공이 향로의 불완전 연소에 영향을 끼치는 것으로 확인되었으며, 배연공과 흡기공의 개폐유무에 따라선 봉황 배연공과 윗줄 배연공은 주로 연기를 배출하는 역할을 하며 아랫줄 흡기공은 주로 흡기구 역할을 한다는 것을 이번 실험을 통해 알 수 있었다.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2006년도 제33회 KOSCO SYMPOSIUM 논문집
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• pp.253-259
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• 2006

The effect of DC electric fields on the flame extinction was investigated experimentally in counterflow configurations for the methane/oxygen/nitrogen diffusion flame. The electric fields was applied by connecting the high voltage and ground terminals to the upper and lower burners, respectively. In case of having electric fields, several modes of flame extinction was observed according to the electric field intensity and strain rate defined by the exit velocity. To visualize and characterize the flame structure and intensity, planar LIF technique was adopted for OH radicals. Consequently, several length scales, including the flame width, thickness, and height from the burner tip, were introduced to explain the various flame behaviors and to characterize the flame extinctions. It was found that the variation of flame width and the chemical reaction are strongly related to a critical electric field intensity, thus the various modes of diffusion flame extinction could be observed due to the electric fields.

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2005년도 추계학술대회 논문집
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• pp.69-73
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• 2005

Three-dimensional density distributions of an impinging and eccentric flame have been analyzed numerically and experimentally by a combined optical system with a digital speckle tomography. The flame has been ignited by premixed butane/air from air holes and impinged vertically against a plate located at the upper side of tile burner nozzle. In order to compare with experimental data, computer synthesized phantoms of impinging and eccentric flames have been made and reconstructed by a developed three-dimensional multiplicative algebraic reconstruction technique (MART). A new scanning technique has been developed for the analysis of speckle displacements to investigate wall jet regions of the impinging flame including sharp variation of the flow direction and pressure gradient. The reconstructed temperatures have been compared with a temperature photography by an infrared camera and results of numerical analysis using a finite-element method.

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2004년도 추계학술대회 논문집
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• pp.34-35
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• 2004

Three dimensional density distributions of impinging and eccentric flames have been investigated by digital speckle tomography. The flames have been ignited by a mixture of butane and air from a circular nozzle and impinged against a plate located at the upper side of the burner exit. For comparison with experimental data, computer synthesized phantoms of impinging and eccentric flames have been reconstructed by a developed three-dimensional multiplicative algebraic reconstruction technique (MART). The advanced reconstruction in the stagnation flow region involved the sharp change of the flow direction and pressure gradient has been developed using a cross-correlation method and new scanning technique for the speckle displacement.

• 한국안전학회지
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• 제15권3호
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• pp.23-29
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• 2000

The objective of this paper is to study burst through the influence of overheating to affect a seamed container using the cookers with different materials and bottom sizes. Following result are drawn from this study; When bottom size of the roast meat had 24cm diameter, the upper part temperature of a seamed container was increased over $40^{\circ}C$. Therefore the cooker material without regard to cooker size had a great influence on the temperature of seamed container. For the natural stone plate which had bottom length 65cm, a seamed container was burst at the cooker temperature $801^{\circ}C$, the surface temperature of a burner $573^{\circ}C$. the upside temperature of seamed container $379^{\circ}C$, the downside temperature of seamed container $236^{\circ}C$ and ambient temperature $34^{\circ}C$. For the cooker of the same bottom area, the stone plate had greater influence on effect of temperature than aluminium cooker. Overheating had a great influence on the seamed container if the bottom or upside diameter of a cooker had been larger than a trivet.

• 대한한방내과학회지
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• 제21권5호
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• pp.697-704
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• 2000

According to herbalogical bibligraphy and literature, therapeutic effects of Achyranthis Radix on arthritis was as follows, 1. Achyranthis Radix of Amaranthaceae is divided into five species-Achyranthes japonica, A. bidentata, A. longifolia, A. fauriei, Cyathula capitata, C. officialis and the characteristic, taste, channel entry, effects and main treatments were alike. 2. Winefrying stood for repairing treatement method for Achyranthis Radix Before repairing treatment method, Achyranthis Radix had three tastes(bitter, sour, and sweet) and calm and not poisoning characteristic. After repairing treatment method, the bitter taste was disappeared, and calm and not poisoning characteristic was changed into warm characteristic. 3. Effects of Achyranthis Radix were quicking the blood and dispelling stasis, liver-kidney supplement and strengthening musculo-skeletal system. Main treatments were relief of lumbar and knee joint pain, static menstrural block and wind-cold- damp impediment. 4. Contraindication of Achyranthis Radix was sympthom caused by spleen-kidney yang vacuity, upper burner disease and lower burner hemorrhage etc. Being used in pregnant woman, it could incur abortion. 5. Contraindication of Achyranthis Radix was beef, milk and mutton. It's fear was Radix Cynanchi Stauntonii and Semen Plantaginis. It's aversion was the firefly. Herba Taraxaci, Carapax Amydae, Carapax Testudinis and Radix Cynanchi Stauntonii. From above results, I suppose Achyranthis Radix has enough herbalogical foundation and could be used to treat arthritis and it is necessary to make a profound study of it.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2017년도 제48회 춘계학술대회논문집
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• pp.104-107
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• 2017

9톤급 다단연소 사이클 엔진 개발을 위한 기술검증시제(TDM0) 파워팩 연소시험이 나로우주센터 3단 엔진 시험설비에서 수행되었다. 기술검증시제 파워팩 모델은 주연소기를 제외한 예연소기와 터보펌프, 추진제 공급시스템으로 구성되어 있다. 파워팩 연소시험에서는 파워팩 구성품들간의 연계 작동성을 확인하였으며, 엔진 시스템 시험을 위한 파워팩의 주요 성능 변수들을 평가하였다.

• 한국수소및신에너지학회논문집
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• 제30권6호
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• pp.593-600
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• 2019

The combustion characteristics of methane/hydrogen pre-mixed flame have been investigated with swirl stabilized flame in a laboratory-scale pre-mixed combustor with constant heat load of 5.81 kW. Hydrogen/methane fuel and air were mixed in a pre-mixer and introduced to the combustor through a burner nozzle with different degrees of swirl angle. The effects of hydrogen addition and swirl intensity on the combustion characteristics of pre-mixed methane flames were examined using particle image velocimetry (PIV), micro-thermocouples, various optical interference filters and gas analyzers to provide information about flow velocity, temperature distributions, and species concentrations of the reaction field. The results show that higher swirl intensity creates more recirculation flow, which reduces the temperature of the reaction zone and, consequently, reduces the thermal NO production. The distributions of flame radicals (OH, CH, C₂) are dependent more on the swirl intensity than the percentage of hydrogen added to methane fuel. The NO concentration at the upper part of the reaction zone is increased with an increase in hydrogen content in the fuel mixture because higher combustibility of hydrogen assists to promote faster chemical reaction, enabling more expansion of the gases at the upper part of the reaction zone, which reduces the recirculation flow. The CO concentration in the reaction zone is reduced with an increase in hydrogen content because the amount of C content is relatively decreased.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.1686-1691
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• 2004

The effect of recirculated exhaust gas on performance and exhaust emissions with FGR rate are investigated by using a natural circulation, pressurized draft and water tube boiler with FGR system operating at several boiler loads and over fire air(OFA) damper openings. The purpose of this study is to apply the FGR system to a power plant boiler for reducing $NO_{x}$ emissions. To activate the combustion, the suction damper of two stage combustion system installed in the upper side of wind box is opened by handling the lever between $0^{\circ}$ and $90^{\circ}$ , and the OFA with 0 to 20% into the flame is supplied, as the combustion air supplied to burner is reduced. It is found that the fuel consumption rate divided by evaporation rate does not show an obvious tendency to increase or decrease with rising the FOR rate, and $NO_{x}$ emissions are decreased, at the same OF A damper opening, as FOR rates are elevated and boiler loads are dropped.