• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.603-607
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• 2011

Structure of flashback and reignition occurring near flameholder was experimentally investigated in a model combustor with V-gutter flameholder. The combustor has a long duct shape with cross section of $40{\times}40mm$ and City Nature Gas(CNG) were used as fuel. Measurements of chemiluminescence with high speed camera was used for visualization of flame structure. In the lean case, flashback distance depend on equivalent ratio. New flame occurred at the front tip of flameholder when flashback. Flashback flame moved toward downstream direction of combustor because mixture flow velocity had increased, and then re-ignition was caused by entering flow into recirculation zone that is formed behind the flameholder.

• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.5
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• pp.121-131
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• 2013

The characteristics of flame dynamics occurring near the bluff body was experimentally investigated in a model combustor with V-gutter bluff body. Measurements of chemiluminescence with high speed camera and PIV were performed for visualization of flame structure. Flashback occurs due to the change of pressure gradient in the combustor, and the flashback distance depends on equivalent ratio. Unstable flames can be classified into three types depending on the flashback distance and structure. When the flame goes over the bluff body, an unusual flame structure occurs at the front of the bluff body. Re-stabilization takes place as the flame moves downstream of the combustor. This process is supported by a strong vortex structure behind the bluff body.

• Journal of Energy Engineering
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• v.9 no.2
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• pp.109-116
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• 2000

저발열량 석탄가스의 thermal/fuel NOx 생성특성과 화염 안정성을 규명하기 위한 실험적 연구를 수행하였다. 저발열량 합성 연료 가스는 일산화탄소, 수소, 질소 및 암모니아를 천연가스 연료와 동일한 입열량을 가지도록 혼합하여 만들었고 , 합성가스는 평면 화염 버너를 공급하여 태웠다. 특정한 합성가스에 대해 당량비를 변화시켜 가며, 비화 또는 역화에 의한 화염안정성을 규명하였고 안정된 화염 영역을 정의하였다. 저발열향 합성가스의 연소시 발생하는 thermal 및 fuel NOx를 측정하여 천연가스 연소시의 경우와 비교하였다.

• Journal of the Korean Institute of Gas
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• v.23 no.5
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• pp.24-34
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• 2019

In this study, the experimental studies were conducted to analyzing characteristics of combustion and flame stabilizing according to with and without water tube in boiler. The burner has consisted of SiC foam where has the location of submerged flame between a ceramic board acting as flash-back arrestor. Porous burner is also insulated to minimize heat loss in the radial direction. In the condition of fixed equivalence ratio, the flame mode was divided into three stability zones by the flow rate. The main factor for blow-off and flash-back depends on mixture flow rate. Consequently, the case of burner with water-tube has higher NOx emissions than without case. This result explains that the presence of water-tube makes the heat loss resistant to ambient temperature with increasing of NOx. This tendency was proved by predicting the relationship between O₂ emission and NO production rate, and by analysing temperature profiles.

• 한국연소학회:학술대회논문집
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• 2015.12a
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• pp.237-240
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• 2015

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.7
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• pp.79-88
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• 2006

In the present paper, the swirl flow structure and flame characteristics of turbulent premixed combustion in a model gas turbine combustor are investigated using large eddy simulation(LES). A G-equation flamelet model is employed to simulate the unsteady flame behavior. When inlet swirl number is increased, the distinct flow structures, such as the shapes of corner recirculation and center toroidal recirculation zone, are observed and the flame length is shorted gradually. Also, the phenomena of flashback are identified at strong swirl intensity. In order to get the accurate description of unsteady flame behavior, the predictive ability of the acoustic wave in a combustor is primarily evaluated. It is found that the vortex generated near the edge of step plays an important role in the flame fluctuation. Finally it is examined systematically that the flame and heat release fluctuation are coupled strongly to the vortex shedding generated by swirl flow and acoustic wave propagation from the analysis of flame-vortex interaction.

• Journal of Energy Engineering
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• v.8 no.1
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• pp.174-180
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• 1999

본 연구는 여러 종류의 연소가스들의 연소 특성변수를 판단하여 각 가스들 간의 교체 가능성을 조사하는 것을 목적으로 하고 있다. 천연가스, 메탄가스, IGCC 생성가스의 연소특성, 즉 역화, 비화, 및 황염형성을 분제 버너를 이용하여 판단하였고, 실험 데이터는 연소 다이어그램 상에서 이론 공기량 분률과 입열로 표현하였다. 실험 결과, 메탄은 천연가스와 아무런 운전조건의 변화없이 호환가능하나, 천연가스를 IGCC 생성가스로 치환하고자 할 경우는 화염 안정으로 인하여 버너의 운전변수를 조절하여야만 한다. 이러한 연구결과는 다양한 산지에 따른 각종 천연가스들의 교체가능성 및 타 연료와의 호환가능성을 판단하는 기초자료로 사용될 수 있다.

• Journal of the Korean Institute of Gas
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• v.16 no.4
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• pp.52-58
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• 2012

Recently, waste gas incineration is increasing due to strong environmental regulatory system in Korea. These incinerating facilities are usually connected with the top of the storage tank through pipeline and incinerate off gas with the flame. Therefore, the flame originated from these facilities is likely to move back into pipeline and might cause an explosion of the storage tank. Accordingly, the purpose of this study is to suggest the preventive measures and the way to improve the safety of these incineration systems through the cause analysis of a major industrial accident occurred in a acrylic acid manufacturing process in Korea. As a result of the study, the preventive measures are suggested as follows. (1) Air or inert gas inflow facilities should be well designed to dilute flammable gases into air or inert gas sufficiently before the blower is restarted in order to prevent the explosion (2) It is needed for the detonation-type flame arresters to be installed on the top of the storage tanks. (3) In case of using the deflagration-type flame arresters, it is necessary to install a rupture disk before the arresters, or blow off the flame outside tanks by connecting the tank top and the incinerator with hood-type pipe. (4) TDR should be installed to be restarted automatically after the momentary power failure.

• Transactions of the Korean hydrogen and new energy society
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• v.33 no.6
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• pp.776-785
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• 2022

Hydrogen combustion in modern gas-turbine engine is the cutting edge technology as carbon-free energy conversion system. Flashback of hydrogen flame, however, is inevitable and critical specially for premixed hydrogen combustion. Therefore, this experimental investigation is conducted to understand flashback phenomenon in premixed hydrogen combustion. In order to investigate flashback characteristics in premixed hydrogen (H₂)/air flame, we focus on pressure conditions and nozzle shapes. In general, quenching distance reduces as pressure of combustion chamber increases, causing flashback from boundary layer near wall. The flashback regime for reference and modified candidate configurations can broadly appear with increasing combustion chamber pressure. The later one can improve flashback-resist by compensating flow velocity at wall. Also, improved wall flow velocity profile of suggested contraction nozzle prevents entire flashback but causes local flashback at nozzle exit.

• Transactions of the Korean hydrogen and new energy society
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• v.21 no.6
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• pp.561-569
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• 2010

The present study deals with experimental investigations on the syngas-oxygen combustion characteristics of a swirl-stabilized premixed flame in a 10 kW combustor. The effect of hydrogen in syngas has been investigated with different swirl angles to identify the role of hydrogen and swirl strength on the flame stability and CO emissions. The results show that hydrogen addition extended the blowout limit while narrowing the flashback limit. The dependence of blowout on the swirl angle is negligible while the dependence of flashback on the swirl angle is evidenced by two regimes depending on the amount of hydrogen. CO emission is decreased with increasing excess $O_2$ supply or increasing hydrogen content. Chemiluminescence diagnostics is utilized to provide information on the structure of a swirl-stabilized premixed flame. The OH chemiluminescence intensity is more concentrated near the burner exit with an increase in the hydrogen content, which results from high reactivity of hydrogen.