• 한국연소학회:학술대회논문집
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• 한국연소학회 2006년도 제33회 KOSCO SYMPOSIUM 논문집
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• pp.137-144
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• 2006

Oil-fired power plants usually use several burners and the combustion air is supplied to each burner through the complicated duct which is called windbox. A windbox should be designed to supply combustion air to each burner evenly but, due to the complicated duct shape, flow distribution in the windbox is unbalanced and uneven supplies of combustion air to each burner are induced by these unbalanced flow distribution in the windbox. These flow patterns tend to make flame unstable, increase the formation of pollutants and lower the overall combustion efficiency. To prevent these disadvantages, flow patterns in the windbox should be investigated for the uniform flow distribution. In this study, computational simulation method was used to investigate the flow distribution in the windbox and measured the velocities at the exit of burners in the real windbox to compare with CFD results. The results show two significant flow patterns. One is that the flow rates of each burner are different from each other and this means that all burners operate in different conditions of air to fuel ratio. The other is that the flow distribution at the exit of each burner is not axi-symmetric although the burner shape is axi-symmetric and this increases the pollutant products like CO.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2005년도 제31회 KOSCO SYMPOSIUM 논문집
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• pp.85-92
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• 2005

Oil-fired power plants usually use several burners and the combustion air is supplied to each burner through the complicated duct which is called windbox. A windbox should be designed to supply combustion air to each burner evenly but, due to the complicated duct shape, flow distribution in the windbox is unbalanced and uneven supplies of combustion air to each burner are induced by these unbalanced flow distribution in the windbox. These flow patterns tend to make flame unstable, increase the formation of pollutants and lower the overall combustion efficiency. To prevent these disadvantages, flow patterns in the windbox should be investigated for the uniform flow distribution. In this study, computational simulation method was used to investigate the flow distribution in the windbox and measured the velocities at the exit of burners in the real windbox to compare with CFD results. The results show two significant flow patterns. One is that the flow rates of each burner are different from each other and this means that all burners operate in different conditions of air to fuel ratio. The other is that the flow distribution at the exit of each burner is not axi-symmetric although the burner shape is axi-symmetric and this increases the pollutant products like CO.

• 한국연소학회지
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• 제9권3호
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• pp.36-43
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• 2004

The flame patterns were investigated in an oscillating combustion burner equipped with a specially designed proportioning valve. The proportioning valve is driven by a solenoid and has an elastomer part which controls the valve opening area. For characterizing the valve, nozzle exit velocities were measured with a hot wire anemometry. The flame patterns were investigated by direct photographing methods using a high speed camera and a digital camera. The results show that the nozzle exit velocities could be controlled diversely and rapidly changed, so the valve seemed appropriate for the oscillating combustion burner application. Mushroom shape and highly wrinkled structure were typical features of the flames in the oscillating combustion burner. As the oscillating intensity of the fuel flow increased, the flame length was shortened.

• 한국연소학회지
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• 제11권1호
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• pp.1-10
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• 2006

Oil-fired power plant usually uses several burners and combustion air is supplied to each burner through the complicated duct which is called windbox. A windbox should be designed to supply combustion air to each burner uniformly but, due to the complicated duct shape, flow distribution in the windbox is unbalanced and non-uniform supplies of combustion air are induced by these unbalanced flows in the windbox. These flow patterns tend to make flame unstable, increase the formation of pollutants and lower the overall combustion efficiency. To prevent these disadvantages, flow patterns in the windbox should be investigated for the uniform flow distribution. In this study, computational simulation method was used to investigate the flow distribution in a windbox and measured the velocities at the exit of burners in a real windbox and model tests to compare with CFD results. The results show two significant flow patterns. One is that the flow rates of each burner are different from each other and this means that all burners operate in different conditions of air to fuel ratio. The other is that the flow distribution at the exit of each burner is not axi-symmetric although the burner shape is axi-symmetric. Additionally some modifications of windbox shape and installation of baffles were proposed to make the uniform flow in the windox.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2004년도 제29회 KOSCI SYMPOSIUM 논문집
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• pp.130-137
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• 2004

The flame patterns were investigated in an oscillating combustion burner equipped with a proportioning valve. The proportioning valve is driven by a solenoid and has an elastomer part which controls the valve opening area. For characterizing the valve, nozzle exit velocities were measured with a Hot Wire Anemometry. The flame patterns were investigated by direct photographing methods using a high speed camera and a digital camera. The results show that the nozzle exit velocities could be controlled diversely and rose up and fell down abruptly, so the valve seemed appropriate for the application for the oscillating combustion burner. Mushroom shaped and highly wrinkled flames were a typical features of the oscillating combustion burner. As the oscillating intensity of the fuel flow increased, the flame length was shortened.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2862-2867
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• 2008

High-temperature components of gas turbine operated for certain period of time can be reused by being repaired or rejuvenated. In case of the gas turbine combustion liners, the biggest and the most important one in the high-temperature components, come in a repair shop after operated for 8,000 or 12,000 hours according to the model and go through the repair and rejuvenation in order to be reused. A stated combustion liner is the first channel which has the combustion gas reached a nozzle from a fuel nozzle. Materials and coating properties of old and new model combustion liners were investigated. To repair these components after the visual inspection, the coatings of combustion liners were removed and then FPI(Fluorescent Penetrant Inspection), a kind of the NDI(Non-Destructive Inspection), was conducted. Damage patterns and the number of the damaged components were classified and analyzed based on data provided from the visual inspection over a long period of time. Focusing on the difference between old model and new model combustion liners, we analyzed the damage distribution and changes and consequently concluded that new model combustion liner would increase repair rate.

• 한국화재소방학회논문지
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• 제28권4호
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• pp.14-20
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• 2014

본 연구는 인화성 액체를 특정 용기에 담유하고 구획된 공간에서 연소 실험을 실시하여 연소 패턴을 분석하는 데 있다. 담유 실험에 사용된 용기는 깊이 20 mm, 넓이 150 mm의 플라스틱이다. 화염이 착화되어 연소되는 과정은 디지털카메라(digital camera) 및 비디오카메라(video camera)를 이용하여 확보하였다. 화염이 최성기에 도달하는 속도는 벤젠이 가장 빠르고 약 60 s이다. 반면 가장 늦게 것은 알코올이었으며 약 360.0 s로 6배 정도 차이가 있었다. 화염이 최성기에 도달하였을 때 플라스틱 용기와 인화성 액체가 동시에 연소됨에 따라 연기는 대부분 검정색이었다. 연소가 완료된 후유증 검지관(crime investigation tube)을 이용하여 유증을 조사한 결과 대두유를 제외한 모든 인화성 물질에서 유증 채취가 가능했다. 즉, 연소 물질의 종류에 따라 화재의 확산 속도 및 패턴 등에 큰 차이가 있다는 것을 알 수 있었다.

• 한국연소학회지
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• 제21권2호
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• pp.15-21
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• 2016

Flame characteristics and combustion stability of a swirl coaxial injector are studied experimentally. Characteristics of flame and combustion instability are analyzed with the parameter of MFR (momentum flux ratio) using hexane instead of kerosene. Flame patterns of blue and yellow are changed with variable MFR. Combustion instabilities are measured and analyzed by adopting a model chamber. Combustion instability mapping is made by evaluating damping factor at the 2 L (second longitudinal) mode with variable MFR in 63 cases for operating condition.

• International Journal of Aeronautical and Space Sciences
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• 제13권4호
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• pp.507-514
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• 2012

The present study is the analyses of what has been attempted and what was understood in terms of improving the regression rate and enlarging the basic understanding of internal flow dynamics. The first part is mainly intended to assess the role of helical grain configuration in the regression rate inside the hybrid rocket motor. To improve the regression rate, a combination of swirl (which is an active method) and helical grain (which is a passive method) was adopted. The second part is devoted to the internal flow dynamics of hybrid rocket combustion. A large eddy simulation was also performed with an objective of understanding the origin of isolated surface roughness patterns seen in several recent experiments. Several turbulent statistics and correlations indicate that the wall injection drastically changes the characteristics of the near-wall turbulence. Contours of instantaneous streamwise velocity in the plane close to the wall clearly show that the structural feature has been significantly altered by the application of wall injection, which is reminiscent of the isolated roughness patterns found in several experiments.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2004년도 제28회 KOSCO SYMPOSIUM 논문집
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• pp.199-206
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• 2004

In the multi-burner power plant, uneven supplies of combustion air to multi-burner are induced by unbalanced flow distribution in the windbox. These flow patterns tend to make flame unstable, increase the formation of pollutants and lower the overall combustion efficiency. To prevent these disadvantages, flow patterns in the windbox should be investigated and made to be distributed uniformly, In this study, scaled windbox model was used for tests and measured the velocities at the exit of the each burner and compared those with the CFD results.