• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.3
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• pp.261-269
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• 2015

In this study, numerical analysis of curved channel steam-methanol reformer was conducted using the computational fluid dynamics (CFD) commercial code STAR-CCM. A pre-numerical analysis of reference model with a cylindrical channel reactor was performed to validate the combustion model of the CFD commercial code. The result of advance validation was in agreement with reference model over 95%. After completing the validation, a curved channel reactor was designed to determine the effects of shape and length of flow path on methanol conversion efficiency and generation of hydrogen. Numerical analysis of the curved-channel reformer was conducted under various flow rate ($10/15/20{\mu}l/min$). As a result, the characteristics of flow and mass transfer were confirmed in the cylindrical channel and curved channel reactor, and useful information about methanol conversion efficiency and hydrogen generation was obtained for various flow rate.

• Journal of Energy Engineering
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• v.6 no.2
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• pp.203-211
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• 1997

This study is on the separation of Global warming effect gas, CO$_2$by chemical absorption from mixture of CO$_2$-N$_2$which was modeled after flue gas of fire power plant. Investigation of optimum condition for absorbent was carried out by using sparged vessel apparatus. Through packed tower experiments, applicabilities of two absorption models were tested by comparing experimental results with theoretical values. Absorbent used in the experiments was Monoethanolamine (MEA) and gas mixture was made in the mole composition of 15% CO$_2$and 85% N$_2$. Through estimations of CO$_2$loading and CO$_2$removal efficiency, optimum concentration of absorbent was found in the range of 4-5 M. To find a rate of absorption, an enhancement factor was introduced. Values of rate of absorption were calculated by Film model and Higbie model, respectively. Higbie model showed good agreement with experimental results. Therefore, this models is considered to be applicable to the CO$_2$separation process for flue gas from fire power plant.

• Journal of the Korean Society of Propulsion Engineers
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• v.18 no.6
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• pp.59-67
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• 2014

Acceptance level random vibration and life firing test for development model of 1 N-class monopropellant thruster have been performed. From the results of random vibration, the natural frequency of the dual thurst module composed of 1 N-class development model thrusters was higher than the part level requirement(>100 Hz) and the structural robustness was verified. Thrust decrease of steady sate was below 7% and thrust instability was within ${\pm}5%$ in the life firing test using over 20 kg propellant throughput. The computerized tomography for catalyst bed showed a less than 7% of catalyst loss and it revealed the design appropriateness of the current thruster development model.

• Transactions of the Korean Society of Mechanical Engineers
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• v.9 no.6
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• pp.810-820
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• 1985

배기 decoupling chamber룰 갖고 있는 맥동 연소 급수가열기에 대한 수학적인 모델링과 관련된 컴퓨터 시뮬레이션을 하였고, 이 때 계에 대한 맥동 현상과 관련된 열적 및 동적 특성을 고려 였다. 시뮬레이션결과 시동기간에 대한 계의 각 부분에서 일어나는 열전달, 압력 및 온도를 구 였고 또한 해석의 제한성과 개선의 필요성을 논의하였다. 이 연구에서 얻어진 결과는 도관에서 맥동에 의한 대류열전달을 예측하기 위한 모델을 세우는데 활용될 수 있다.

• Journal of the korean Society of Automotive Engineers
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• v.10 no.2
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• pp.9-14
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• 1988

본 해설에서는 현존 내연기관내의 연소현상에 적용되고 있는 여러 수치적 방법 및 모델에 대한 소개와 주로 유체역학적인 면과 화학반응론적인 면, 화염전파 과정에서의 수치적인 난점들과 그와 같은 수치적 난점들을 유발시키는 물리적 현상 및 그 수치적 난점들을 유발시키는 물리적 현상 및 그 수치적 난점을 해결하는 해결방안을 다루겠으며, 또한 몇가지 내연기관의 연소현상에 대한 수치계산 예를 간략히 소개하고자 한다.

• 한국연소학회:학술대회논문집
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• 2012.11a
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• pp.195-198
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• 2012

Numerical simulation is performed to evaluate the conditional moment closure (CMC) models for spray development, ignition, and turbulent combustion for the Engine Combustion Network (ECN) test cases. The CMC model is implemented in the open source code, OpenFOAM, to provide conditional flame structures through the solution of Eulerian as well as Lagrangian conditional transport equations. In spite of more accurate treatment of the convective term, Eulerian CMC provides similar ignition delays and lift-off lengths with Lagrangian CMC.

• 한국연소학회:학술대회논문집
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• 2012.11a
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• pp.345-347
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• 2012

The secondary air injection influences the flow of the combustion gas in the furnace. Therefore, the analysis of the furnace should be careful in the selection of the turbulent model with CFD. In this study, CFD results of several turbulent models were compared with experimental results. Analysis results suggest to select turbulent models in the furnace secondary air nozzle.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2000.11a
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• pp.207-209
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• 2000

GDI(Gasoline Direct Injection) 기관은 전체적으로 희박한 영역에서 작동되기 때문에 저연비, 고출력화 및 배기유해가스 저감에 매우 유리하다. GDI 기관에 있어서 희박연소를 실현하고자 한 연구는 공기유동 강화방식, 연소실 형상의 최적화, 부실식 연소, 분사된 연료의 미립화, 흡기포트의 형상 변화, 운전조건 변화에 따른 분사전략의 변화 등 그 방식도 다양하며,$^{<1-5>}$ 최근엔 이러한 각 방식들의 장점들을 적절히 활용하고 이에 따라 각기 고유한 모델을 채택하여 접근하려는 시도를 하고 있다$^{<6>}$ . (중략)

• 한국연소학회:학술대회논문집
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• 2015.12a
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• pp.169-172
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• 2015

This paper presents a numerical investigation on kerosene-air mixture detonation and behaviors of thermal elasto-plstic thin metal tube under detonation loading based on multi-material analysis. The detonation loading is modeled by the kerosene-air mixture detonation which is compared with CJ condition and experimental cell size. And the thermal softening effect on elasto-plstic model of metal tube is indicated by different dynamic response of detonation loaded tube in various temperature and tube thickness.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.12
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• pp.35-40
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• 2006

The combustion instability in a model dump combustor with an exhaust nozzle and the possibility of combustion control using a loudspeaker to these instabilities were studied. By changing inlet velocity, combustor length and equivalence ratio, dynamic pressure signals and flame structures were simultaneously taken. Because inlet velocity and combustor length affect the life time of vortex in the dump combustor, the results showed that as the combustor length increased and the inlet velocity decreased, the instability frequency decreased and the maximum power spectral density of the dynamic pressure generally decreased. Also, instability frequency and maximum power spectral density of the dynamic pressure increased with the increment of equivalence ratio. From the data of close-loop control, the optimum time-delay control using a loudspeaker was confirmed to be able to reduce the vortex shedding induced from the mixed acoustic-convective mode combustion instability.