• 대한기계학회논문집B
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• 제28권8호
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• pp.937-944
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• 2004

An experimental study has been conducted to evaluate the effects of $CO_2$ on heat transfer from oxygen-enriched hydrogen flame. Experiments were performed on flames stabilized by a co-flow swirl burner, which was mounted on top of the furnace. Five different oxidizer compositions were prepared by replacing $N_2$ with $CO_2$. In a steady state, the total as well as radiative heat flux from the flame to the wall of furnace have been measured using a heat flux meter. Temperature distribution in furnace also has been measured and compared. By increasing $CO_2$ proportion in the oxidizer, the convection played a more significant role rather than radiation. Overall temperature in the furnace was seen to be decreased, while the total heat flux has increased.

• 한국연소학회지
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• 제10권2호
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• pp.18-25
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• 2005

An experimental study has been conducted to evaluate the effects of reburning on $NO_x$ reduction and also to examine heat transfer characteristics from LPG flame. Experiments were performed in flames stabilized by a co-flow swirl burner, which was mounted at the bottom of the furnace. Tests were conducted using LPG gas as main fuel and also as reburn fuel. The effects of reburn fuel fraction and injecting location of reburn fuel are studied. The paper reports data on flue gas emissions, temperature distribution in furnace and various heat fluxes at the wall for a wide range of experimental conditions. In a steady state, the total as well as radiative heat flux from the flame to the wall of furnace has been measured using a heat flux meter. Temperature distribution and emission formation in furnace have been also measured and compared.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년도 제30회 춘계학술대회논문집
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• pp.67-70
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• 2008

스월 연소기의 비반응 난류 유동특성을 파악하기 위하여 3차원 Large Eddy Simulation(LES)을 수행하였다. 연소기는 GEAE LM6000 연소기를 이용하였으며, 실제 실험 결과에 따른 인젝터 유입 형상을 적용하였다. 주 흐름 부분에서 강한 vortex breakdown, 중심 재순환영역, 모서리 재순환영역, 축방향으로 전진하는 스월링 형상, 주기적으로 나타나는 난류 구조를 관찰하였다. 계산된 결과는 실제 실험결과와 선행연구자들의 LES 계산결과와 비교하여 잘 맞음을 확인하였다.

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2004년도 추계학술대회 논문집
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• pp.102-103
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• 2004

Simultaneous CH and OH planar laser induced fluorescence(PLIF) and stereoscopic particle image velocimetry(PIV) measurements have been developed to investigate the local flame structure of turbulent premixed flames. The developed simultaneous two radical concentrations and three component velocity measurements on a two-dimensional plane was applied for relatively high Renolds number turbulent premixed flames in a swirl stabilized combustor. All measurements were conducted for methane-air premixed flames in the corrugated flamelets regime. Strong three-dimensional fluctuation implies that misunderstanding of the flame/turbulent interactions would be caused by the analysis of two-component velocity distribution in a cross section. Furthermore, comparisons of CH-OH PLIF and three-component velocity field show that the burned gases not always have high-speed velocity in relatively high Renolds number turbulent premixed flame.

• 한국연소학회지
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• 제12권4호
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• pp.14-21
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• 2007

In order to enhance combustion efficiency, oxygen-enriched combustion is used by increasing the oxygen ratio in the oxidizer. However, since the flame temperature increases, NOx formation in the furnace seriously increases for low oxygen enrichment ratio. In this case, reburning is a useful technology for reducing nitric oxide. In this research, experimental studies have been conducted to evaluate the hybrid effects of reburning/selective non-catalytic reaction (SNCR) and reburning/air staging on NOx formation and also to examine heat transfer characteristics in various oxygen-enriched LPG flames. Experiments were performed in flames stabilized by a co-flow swirl burner, which were mounted at the bottom of the furnace. Tests were conducted using LPG gas as main fuel and also as reburn fuel. The paper reported data on flue gas emissions, temperature distribution in furnace and various heat fluxes at the wall for a wide range of experimental conditions. Overall temperature in the furnace, heat fluxes to the wall and NOx generation were observed to increase by low level oxygen-enriched combustion, but due to its hybrid effects of reburning, SNCR and Air staging, NOx concentration in the exhaust have decreased considerably.

• 한국연소학회지
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• 제15권4호
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• pp.37-42
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• 2010

The measurement of heat release rate is of great importance in the study of thermo-acoustic instability occurring in lean premixed combustion and the chemiluminescence emission has been used as an indicator of heat release in combustion instability studies primarily for its relative simplicity. This paper presents results of experimental study of flame chemiluminescence from an atmospheric, swirl-stabilized, turbulent lean premixed flame with a main emphasis on the effect of $CO_2^*$ background level in the $CH^*$ and $OH^*$ band. The test results show that the effect of $CO_2^*$ level in the $CH^*$ band is greater than that in the $OH^*$ band. Also, the background to peak ratio for both $CH^*$ and $OH^*$ bands can be expressed as a function of equivalence ratio, almost regardless of a change in the inlet velocity.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2006년 창립20주년기념 정기학술대회 및 국제워크샵
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• pp.420-425
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• 2006

Measurements results of flow-structure-interactions (FSI) of an air-lifted body are introduced. An adaptive stereoscopic-PIV system has been constructed for the measurements of the air-lifted body. The measurement system consists of two cameras and optical sensors. The flow characteristics around a lifted cylinder body(length=60mmm, diameter =10mm, polystyrene) in the swirling flow field in a vertical pipe (length=600mm, inner diameter=) are investigated by the use of the constructed adaptive stereoscopic-PIV system. The images of the two cameras were used for the analysis of the flow fields around the floated cylinder body. The images of the cylinder body captured by the two cameras were used for the analyses of its motions. Four optical sensors (LED) were used for the detection of the postures of the freely-lifted cylinder body. The FSI analyses have been carried out to find the physical conditions at which the floating body is stabilized with its upright postures.

• 대한기계학회논문집B
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• 제30권8호
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• pp.788-795
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• 2006

From the view of the environmental protection against the use of fossil fuels, the great of efforts have been exerted to find an effective method which is not only pollutant reduction but also high thermal efficiency. Reburning is a useful technology in reducing nitric oxide through injection of a secondary hydrocarbon fuel. In this paper, an experimental study has been conducted to evaluate the hybrid effects of reburning and selective non-catalytic reaction (SNCR) on $NO_x/CO$ reduction from oxygen-enriched LPG flame. Experiments were performed in flames stabilized by a co-flow swirl burner, which was mounted at the bottom of the furnace. Tests were conducted using LPG gas as main fuel and also as reburn fuel. The paper reported data on flue gas emissions, temperature distribution in furnace and various heat fluxes at the wall for a wide range of experimental conditions. Overall temperature in the furnace, heat fluxes to the wall and $NO_x$ generation were observed to increase by oxygen-enriched combustion, but due to its hybrid effects of reburning and SNCR, $NOx/CO$ concentration in the downstream has considerably decreased.

• 한국연소학회지
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• 제14권4호
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• pp.41-47
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• 2009

An experimental study was performed to confirm the effect of the changing combustor pressure(-30~30 kpa), combustion characteristics were investigated by measuring the local chemiluminescence intensity, the local temperature distribution and emission. In order to investigate combustion ones, the combustor pressure index($P^*$) was controlled in the range of 0.7~1.3 for each equivalence ratio in the present combustion system, where $P^*$ is defined as the ratio of absolute pressure to atmospheric one. The local mean temperature showed the uniform distributions for lower pressure index, which increased with increasing equivalence ratio. The mean $OH^*$ chemiluminescence intensity, showed high level for lower pressure index for ${\Phi}{\get}1.0$ conditions. EINOx decreased with decreasing pressure index for overall equivalence ratio conditions.

• 한국연소학회지
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• 제14권4호
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• pp.17-24
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• 2009

Reburning is one of the most useful technologies for reducing nitric oxide in economically and technically. The reburning process was demonstrated as an effective NOx reduction method through injection of a secondary hydrocarbon fuel. An experimental study has been conducted to evaluate the effect of biomass reburning on NOx and CO formation in a light oil flamed combustion furnace. Reburning tests on NOx reduction of air-carried rice husk powder as the reburn fuel and light oil as the main fuel were performed in flames stabilized by a co-flow swirl and fuel staged burner, which was mounted at the front of the furnace. The results included flue gas emissions and temperature distribution in the furnace for several kinds of experimental conditions. It was observed clearly that NOx concentrations in the exhaust have considerably decreased due to effect of biomass reburning. The maximum NOx reduction rate was 42% when the reburn fuel fraction was 0.18. The CO emissions were kept under 42 ppmv in all experimental tests. And this paper makes clear that in order to decrease NOx concentration in the exhaust when the biomass reburning system is adapted, the control of some factors such as reburn fuel fraction and reburn zone fraction is very important.