• Journal of the Korean Society of Propulsion Engineers
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• v.4 no.3
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• pp.38-44
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• 2000

In general liquid rocket nozzles are protected from hot combustion gas by regenerative cooling techniques. But due to the complexity of the cooling system, it causes increase of system cost and frequently source of the system malfunction. Recently, instead of regenerative cooing, ablative material are used to protect combustion chamber wall and nozzle. To determine the nozzle material erosion rate and erosion shape, more than 500 hot fire test were performed by using 100 lb thrust experimental liquid rocket. Test variable were propellant feed sequence, injector, position of igniter and liquid oxygen supply temperature.

• Journal of the korean Society of Automotive Engineers
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• v.3 no.2
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• pp.43-49
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• 1981

연료 연소를 수반하는 장치는 공업계에서 널리 사용되고 있으나, 그 설계에 있어서 확립된 이 론은 거의 없고 대체로 과거의 설계에 따라 설계하고 있는 것이 현상이라 하겠다. 변조장치의 형 식이 정해져 있고, 성능도 거의 알려져 있는 경우에는 위와같은 방법도 좋겠지만 예를 들어 새로 운 형식 변조기나 연소실을 계획할 경우에는 실기와 동규모의 실험장치를 몇 종류 제작하여 그 성능을 실험적으로 비교 검토하여 좋은 것을 찾는 방밥을 취하게 된다. 이러한 방법은 많은 비용이 소요되며 기종이 바뀌면 새로위와 같은 일을 반복하여야 한다. 이와같은 불합리를 없애기 위하여 많은 연구자는 이론적으로 또 실험적으로 연구를 계속해왔다. 그리하여 현재 많은 사 실을 구명하였으나 아직 구체적 이론을 확립하기까지는 이르지못한 실정이다. 이것은 연소란 현상이 아주 복잡하고 또 관계된 인자가 많은 까닭이다. 본 강좌에서는 열체분우연소의 기본을 이루는 액적의 증발과 연소 문제에 대해서 현상적으로 해설하여 기초적 해석에 도움이 되기를 바라는 바이다.

• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.5
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• pp.19-26
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• 2011

In order to investigate the effect of fuel injection hole configuration within the scramjet combustor, experiment and quasi-one-dimensional analysis was performed. And the results were compared with experiment and analysis result which were performed in 2008 with same facility and test condition. Fuel injection hole size was decreased and quantity was increased. However the depth of fuel penetration and flow quantity of fuel were maintained. As a test result, combustion performance was increased significantly with no-cavity injector and slightly with plain-cavity. However, combustion performance with zigzag-cavity was decreased.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.423-431
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• 2010

In order to investigate the effect of fuel injection hole configuration within the scramjet combustor, experiment and quasi-one-dimensional analysis was performed. And the results were compared with experiment and analysis result which were performed in 2008 with same facility and test condition. Fuel injection hole size was decreased and quantity was increased. However the depth of fuel penetration and fuel flow were maintained. As a test result, combustion performance was increased significantly with no-cavity injector and slightly with plain-cavity. However, combustion performance with zigzag-cavity was decreased.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2010.10a
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• pp.257-260
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• 2010

실제 규모 ISO 9705 표준 화재실에서 액체연료를 대상으로 연소효율 개념에 관한 실험적 연구가 수행되었다. 특히 구획 외부에서 측정되는 총괄연소효율과 구획 내부의 고온 상층부에서 측정된 국부연소효율 개념을 비교 검토하였다. 주요 결과로서, 총괄연소효율은 총괄당량비 증가에 따라 비교적 선형적인 감소경향을 보였다. 반면에 국부연소효율은 총괄당량비가 증가함에 따라 2차 곡선의 형태로 크게 감소됨을 확인하였다. 위 결과를 통해 국부연소 효율에 대한 정보는 구획 내부의 화재현상을 이해하는데 유용한 변수임을 알 수 있었다. 또한 국부연소효율은 구획화재의 상사과정에서 중요한 변수로 사용될 수 있음을 논의하였다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2000.11a
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• pp.15-15
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• 2000

두 개의 사각형 유입구가 $90^{\cire}$의 각도를 이루고 있는 액체 램제트 엔진의 연소실 형상을 최적화하기 위해서 수조를 이용한 연소실 유동 계측 실험을 수행하였다. 공기 유입구의 연소실 유입 각도는 $30^{\cire}$, $45^{\cire}$ 및 $60^{\cire}$인 세 가지 형상의 연소실 모형을 제작하였으며, 각각의 유입 각도에 대하여 연소실 재순환 영역의 크기를 5가지로 변화시킬 수 있도록 모형을 제작하였다. 그리고 연소실의 배면은 돔의 형태로 하여 재순환이 잘 이루어지도록 모형을 제작하였으며, 유입구에서 연소실로 들어가는 유동의 안정화를 위해 안내깃을 세 개 설치하여 실험하였다.(중략)

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.187-199
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• 2011

The main objective of this study was investigation of natural gas flames in a lean premixed swirl-stabilized dump combustor with an attention focused on the effect of the various fuel-air mixing section geometry on the combustion instability characteristics. The multi-channel dynamic pressure transducers were located on the combustor and inlet mixing section region to observe combustion pressure oscillation and difference phase at each dynamic pressure measurement results. Dynamic pressures were also measured to investigate characteristics of combustion at the same time. The combustor and mixing section length was varied in order to have different acoustic resonance characteristics from 800 to 1800 mm in combustor and 470, 550, 870 mm in mixing section. We observed two dominant instability frequencies in this study. Lower frequencies were obtained at lower equivalence ratio region and it was associated with a fundamental longitudinal mode of combustor length. Higher frequencies were observed in higher equivalence ratio conditions. It was related to secondary longitudinal mode of coupled with the combustor and mixing section. In this instability characteristics, pressure oscillation of mixing section part was larger than pressure oscillation of combustor. As a result, combustion instability was strongly affected by acoustic characteristics of combustor and mixing section geometry.

• Journal of the Korean Society of Propulsion Engineers
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• v.7 no.4
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• pp.27-32
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• 2003

The Performance of micro combustor in various condition was exploited experimentally. Various geometric conditions of combustor were considered to figure out the performance of micro combustor. The micro combustor studied in this study was constant volume with cylindrical shape. Geometric parameters of combustor were defined to be combustor height and diameter. The effect of height was exploited parametrically with the size of 1mm, 2mm and 3mm. The effect of diameter was observed parameterized with 7.5mm and 15mm. Three different combustibles or Stoichiometric mixture of methane/air, hydrogen/air were used. Pressure transition during combustion process was recorded. The maximum pressure by combustion responded favorably with the change of height of combustor and the initial pressure. The flame propagation was visulized using Schlieren method. The flame propagation within combustor was observed when specific conditions such as combustor height and initial pressure over critical value was satisfied.

• Korean Chemical Engineering Research
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• v.55 no.6
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• pp.846-853
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• 2017

Cold bed and $30kW_{th}$ pilot bed tests using circulating fluidized bed (CFB) were conducted to apply oxy-fuel technology for waste sludge combustion as a carbon capture and storage technology. In cold bed test, the minimum fluidization velocity ($u_{mf}$) and superficial velocity for fast fluidization was determined as 0.120 m/s and 2.5 m/s, respectively. In the pilot test, air and oxy-fuel combustion experiments for waste sludge were conducted using CFB unit. The flue-gas temperature in 21~25% oxy-fuel combustion was higher than that of air and up to 30% oxy-fuel combustion. In addition, the concentration of carbon dioxide was more than 80% with the oxygen injection range from 21% to 25% in oxy-fuel CFB waste sludge combustion.

• Journal of the Korean Society of Propulsion Engineers
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• v.16 no.4
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• pp.57-69
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• 2012

The main objective of this study was investigation of natural gas flames in a lean premixed swirl-stabilized dump combustor with an attention focused on the effect of the various fuel-air mixing section geometry on the combustion instability characteristics. The combustor and mixing section length was varied in order to have different acoustic resonance characteristics from 800 to 1800 mm in combustor and 470, 550, 870 mm in mixing section. We observed two dominant instability frequencies in this study. Lower frequencies were associated with a fundamental longitudinal mode of combustor length. Higher frequencies were related to secondary longitudinal mode of coupled with the combustor and mixing section. As a result, combustion instability was strongly affected by acoustic characteristics of combustor and mixing section geometry.