• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.254-257
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• 2017

As a part of the development of aircraft gas turbines, combustion performance tests have been conducted in the single combustor sector. The effects of change in the amount of air supplied to the main combustion zone to the performance of the combustor, such as a pollutant emission, a liner temperature distribution and an exit temperature patterns, were studied. Emissions of CO and NOx increased with the main air-ratio and exit temperature pattern was improved. When changing the pattern of the dilution holes, it was shown that the temperature patterns on the exit plane of the combustor and the surface of liner changed depending on the main flame structure and mixing with diluent air. These observations will be applied to combustor liner designs to improve combustor durability and emissions reduction performance.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.242-245
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• 2009

The effect of fuel composition on flame length was studied in a non-premixed turbulent diluted hydrogen jet with coaxial air. The observed flame length was expressed as a function of the ratio of coaxial air to fuel jet velocity and compared with a theoretical prediction based on the velocity ratio. Four cases of fuel mixed by volume were determined. In the present study, we derived a scaling correlation for predicting the flame length in a simple jet with coaxial air using the effective jet diameter in the near-field concept. The experimental results showed that visible flame length had a good relation with the theoretical prediction. The scaling analysis is also valid for diluted hydrogen jet flames with varied fuel composition.

• Journal of the Korean Society of Propulsion Engineers
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• v.14 no.5
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• pp.72-83
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• 2010

Experiments were conducted to investigate the effects of added diluents (carbon dioxide, nitrogen, and helium) on cellular instabilities in outwardly propagating spherical syngas-air premixed flames. Laminar burning velocities and Markstein lengths were measured by analyzing high-speed schlieren images at various diluent concentrations and equivalence ratios. Experimental results showed substantial reduction of the laminar burning velocities and of the Markstein lengths with the diluent additions in the fuel blends. Effective Lewis numbers of helium-diluted syngas-air flames increased but those of carbon dioxide- and nitrogen-diluted syngas-air flames decreased in increase of diluents in the reactant mixtures. With helium diluent, the propensity for cells formation was significantly diminished, whereas the cellular instabilities for carbon dioxide- and nitrogen-diluted syngas-air flames were not suppressed.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.2
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• pp.137-143
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• 2013

This study is to develop the production method of stepwise dilution gas for the evaluation of complex odor concentration by orifice tube. The basic orifice tube for 10 and 30 times of dilution sample was made at first, and with the combination of the basic orifice tubes we can continuously manufacture the stepwise dilution sample gas for air dilution sensory test ; 10, 30, 100, 300, 1,000, 3,000 times etc. The hole size of orifice tube was 0.84 mm for 10 times of dilution sample, and was 0.34 mm for 30 times. Dilution sample gas made with the basic orifice tube have an excellent reproducibility, 2%RSD. In addition, over 90% of correlation was shown between the sample made by the orifice tube and the sample by the syringe dilution method. Because there was no concentration drift of dilution gas with changes of connected pump flow, the basic orifice tube could be mounted directly with a vacuum suction box, and could be used simply as a tool for the evaluation of odor, especially on site.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.549-551
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• 2016

In this paper, With the development of modern science and technology are Sheds to stay indoors rather than outdoors space it increased significantly compared to the past. And a wide variety of research about outdoor air quality until recently, efforts are underway but the issue of air quality in the room is the fact that all considered relatively lightly. As the contamination of the room air is polluted, unlike the natural environment, a large outdoor air dilution rate, the dilution rate is very low, once the contaminated air continuously circulating exerts a very bad influence on the health of people staying in the room. In this study, movement characteristics of the person living in a room, the air measuring device for the study of the active indoor environmental control system reflects the life form to measure the quality of the measured air in real time for transmitting the information to the user of the smart devices, alarm bot It was implemented and operational applications.

• 한국전산유체공학회:학술대회논문집
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• 2010.05a
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• pp.491-492
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• 2010

기존에 사용중인 저압용 벤튜리 타입 혼합기는 0.32kg/cm2에서 열리고 0.28kg/cm2에서 닫히도록 설정되어 있다. 이 방식은 증가하는 도시가스 공급량을 따라갈 수 없기 때문에 강제 혼합기를 개발 현장에 적용하고자 한다. 본 연구를 통해서 개발하고자하는 강제 혼합기는 제어밸브을 통하여 가스 62.5%, 압축공기 37.5%의 비율로 희석하여 서지탱크로 보내진다. 완성된 혼합기를 이용한 열량실험 결과 유량이 변하여도 일정한 열량이 나옴을 알 수 있었다.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.6
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• pp.90-99
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• 2002

The main purpose of this study lies on the development of micro dilution tunnel based on the Sierra Dilution chamber model. As a primary examination, characteristics of flow and temperature distributions during the steady dilution process in dilution chamber are observed with numerical analysis. The penetration of dilution air through porous tube as well as wall temperature and temperature gradient inside porous tube are examined. The thermophoretic velocity in terms of temperature behavior inside porous tube are defined and examined. Based on the ratio of penetration and thermophoretic velocities, all part of porous tube are shown to be safe from the particulate depositions. However, The inlet portion of porous tube in addition to the portion of impinging of dilution air are marginally safe from the particulate depositions. Generally the safer design against particulate deposition is required in provision f3r steady dilution process and for transient process as well.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.393-396
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• 2008

The study of nitrogen dilution effect on flame stability was experimentally investigated in non-premixed turbulent lifted hydrogen jet with coaxial air. hydrogen gas was used as a fuel and coaxial air was injected to make flame liftoff. And both of the fuel jet and coaxial air velocity were fixed as $u_F$=200 m/s and $u_A$=16 m/s, while nitrogen diluents mole fraction was varied from 0 to 0.2. For the analysis of flame structure and flame stabilization mechanism, the simultaneous measurement of PIV/OH PLIF had been performed. It was found that the turbulent flame propagation velocity increased as decreasing of nitrogen mole fraction. We concluded that the turbulent flame propagation velocity was expressed as a function of turbulent intensity, even though the mole fraction of nitrogen diluents gas was changed.

• 한국연소학회:학술대회논문집
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• 1999.10a
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• pp.201-207
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• 1999

The combustion characteristics for the low NOx 50 kW-class gas turbine combustor have been experimentally investigated. In order to achieve the premixing and the lean burn combustion, the geometries of the primary zone including premixed chamber were modified from conventional combustor. The centerline profiles of CO and NO concentration, and temperature were measured for the premixed combustors with or without dilution holes in the liner. The effects of the pilot fuel injection rate and air dilution on flame stabilization and pollutant (CO, NO) emission are discussed in detail.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.4
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• pp.651-659
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• 2000

The characteristics of ammonia removal by natural neutralizer were studied by using a scrubber type equipment. As operation parameters, neutralizer dilution ratio, neutralizer inlet flowrate, air flowrate and initial ammonia concentration were selected and their effects on ammonia removal efficiency were investigated. The optimal removal effect was achieved at neutralizer dilution ratio of 1.0% and neutralizer inlet flowrate of $60m{\ell}/min$. On the other hand, with respect to air flowrate and initial ammonia concentration, there was no significant effect on removal efficiency, when loading rate was considered. In addition, ammonia removal reaction was investigated by analyzing the ammonia oxides, such as nitrites and nitrates, after reacting ammonium solution with natural neutralizer. The result shows a partial oxidation by natural neutralizer besides dominant absorption of ammonia.