• 한국연소학회:학술대회논문집
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• 2000.12a
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• pp.47-58
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• 2000

The relationship among the flame radiation, NOx emissions, residence time, and global strain rate are examined for turbulent non-premixed jet flames with wide variations in coaxial air conditions. Measurements of NOx emission, flame geometry and flame radiation were made to explain the NOx emission scaling based on global parameters such as flame residence time, global strain rate, and radiant fraction. The overall 1/2-power scaling is observed in coaxial air flames, irrespective of coaxial air conditions, but the degree of deviation from the l/2-slope curve in each case differs from one another. From the comparison between the results of pure hydrogen flames and those of helium diluted hydrogen flames, it is observed that flame radiation plays a significant role in pure hydrogen flames with coaxial air and the deviation from 1/2-power scaling may be explained in two reasons: the difference in the flame radiation and the difference in jet similarity in coaxial air flames. From the radiation measurements, more detailed explanations on these deviations were suggested.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.4
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• pp.291-298
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• 2007

The purpose of this study is to evaluate the efficacy of multizone simulation that enables to grasp of details about microbial contaminant problem in an multistoried apartment. We used actual indoor test data to figure up microbial contaminant level as initial value for the multizone simulation and estimated the various effects of indoor occupant infected with germs such as bacteria and fungus and the performance of air sterilization by using multizone simulation in substitute for infeasible experimental approach. The results show that natural ventilation make ourselves generally useful for removing indoor microbial contaminants. The results also show that the performance of air sterilization reach the maximum in the case of using mechanical ventilation and UVGI air sterilizer. The conclusion is that this multizone simulation is useful tool for actual design method for immune building systems.

• 연구논문집
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• s.31
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• pp.23-43
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• 2001

An experimental investigation on the reduction of nitrogen oxide emission from swirling, turbulent diffusion flames was conducted using multi air staged combustor, The combustor utilizes swirler to dampen fuel/air mixing, allowing an extended residence time for fuel pyrolysis and fuel-N conversion chemistry in an locally fuel-rich environment prior to burnout. This process also allow to reduce thermal NOx formation to lessen the temperature of reaction zone. The aerodynamic process therefore emulates the conventional staged combustion process, but without the need for the physically separate fuel-rich and -lean stages. Parametric studies on the ratios of each staged air and droplet size were carried out the feasibility of fuel/air mixing for low NOx combustion with diesel and pyridine mixed diesel fuel oil.

• Journal of Mechanical Science and Technology
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• v.14 no.1
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• pp.103-112
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• 2000

Numerical simulations of unsteady opposed-flow flames are performed using an adaptive time integration method designed for differential-algebraic systems. The compressibility effect is considered in deriving the system of equations, such that the numerical difficulties associated with a high-index system are alleviated. The numerical method is implemented for systems with detailed chemical mechanisms and transport properties by utilizing the Chemkin software. Two test simulations are performeds hydrogen/air diffusion flames with an oscillatory strain rate and transient ignition of methane against heated air. Both results show that the rapid transient behavior is successfully captured by the numerical method.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.8.1-8.1
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• 2005

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2000.11a
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• pp.324-325
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• 2000

대기 오염 성분에 대한 연구 뿐 만 아니라 반도체 가공 현장의 환경평가를 위한 미량 기체의 효과적인 포집 및 정량 방법이 요구되고 있다(Lue, S. J., 1999). 이들 오염원은 대부분 pub 이하의 농도로 존재하며 순간적으로 변화하므로 분석을 위해서는 연속적으로 여러 원소를 감시할 수 있는 장비가 효과적이다. 이러한 관점에서 스크러버 형태의 확산 포집기와 이온 크로마토그래피를 이용한 대기중 미량 기체의 연속 정량법이 가장 효과적이다. (중략)

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2002.04a
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• pp.285-286
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• 2002

자동차의 주행에 의한 이산화질소(또는 부유 입자성 물질)의 환경영향평가는 인간의 건강과 생활환경의 보전의 관점에서 주거 등을 대상으로 하고 있다. 조사는 예측에 필요한 background 농도의 설정을 위해 현 상태의 농도파악과 예측에 사용되는 기상data의 설정을 목적으로 하며, plume식 및 puff식을 사용하여 이산화질소(또는 부유 입자성 물질)의 연평균을 예측한다. 예측결과로부터, 환경영향이 없거나 삭은 경우로 판단되지 않는 경우에 환경보전조치를 검토한다. 이러한 예측을 보다 손쉽게 하기 위해서 본 시스템을 개발하였다. (중략)

• 전기의세계
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• v.26 no.2
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• pp.95-98
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• 1977

Commercially available fuel oil for power plant contains relatively much sulphur, which means accordingly high content sulphur deoxide in exhaust gas. Sulphur deoxide has been identified as the worst-pollutant caused by thermal power generation. This paper primarily deals with the stack gas diffusion effects of various parameters, namely vertical stability, wind velocity, exhaust gas velocity, stack height, etc., on the ground concentration. thereof the relation between stack height and maximum plant capacity is analyzed from the standpoint of air pollution prevention. The limit capacity is calculated by means of mean concentration introducing Mead and Lowry coefficient respectively.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.2
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• pp.168-172
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• 2003

The electron transport coefficients in Air is analysed in range of E/Nvalues from 100~1000(Td) by a MCS and BE method. This paper have calculated W, ND$\sub$L/, ND$\sub$T/, Mean energy mixtures by N$_2$+O$_2$. The results gained that the values of the electron swarm parameters such as the electron drift velocity, longitudinal and transverse diffusion coefficients.

• 한국전산유체공학회:학술대회논문집
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• 2009.04a
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• pp.176-182
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• 2009

In the present study, a numerical simulation for the diffusion of hydrogen jet in a enclosure was performed to aid the leakage test of the hydrogen for the safety of the hydrogen vehicle. The temporal and spatial distributions of the hydrogen concentration in the test chamber are predicted from the present numerical analyses. Flammable region of 4-74% and explosive region of 18-59% hydrogen by volume was identified from the present results. Factors influencing the diffusion of the hydrogen jet were examined to evaluate the effectiveness of forced ventilation for relieving the accumulation of the leaked hydrogen gas in the chamber, which include location of open windows, size of leakage nozzle, and leakage rate among others. The distribution of the concentration of the leaked hydrogen for various cases can be used as a database in various applications for the hydrogen safety.