• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.04a
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• pp.143-147
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• 2007

Kerosene and diesel are compounded fuels with various types of hydrocarbon elements and difficult to model the chemical kinetics. This study focuses on the prediction of the non-equilibrium reaction of fuel-rich combustion with detailed kinetics developed by Dagaut using PSR(perfectly stirred reactor) assumption. In Dagaut's surrogate model for kerosene and diesel, chemical kinetics consists of 2352 reaction steps with 298 chemical species. Also, Frenklach's soot model was implemented along with detailed kinetics to calculate the gas properties of fuel rich combustion efflux.

• Proceedings of the Korea Information Processing Society Conference
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• 2022.05a
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• pp.294-297
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• 2022

본 논문에서는 비평탄 지형 보행이 가능한 이동형 로봇의 설계 최종 목적에 최적화된 12자유도 소형 4족 로봇의 하드웨어를 설계하였으며, 비평탄 지형을 극복하기 위한 지능적인 보행을 설계하고 그에 따른 각 관절별 모터들의 용량을 분석하고 시뮬레이션을 통해 최적의 파라미터값들을 도출한다

• Journal of Korean Society of Environmental Engineers
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• v.30 no.2
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• pp.190-198
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• 2008

In this stduy, the column experiments were carried out assuming the soil was contaminated by leakage of gasoline containing MTBE from USTs and pipes around gas stations. Then, characteristics of MTBE transport in the soil were investigated using CXTFIT program. The column experiments with different soil properties, moisture content, organic matter content and flow rate were carried out. Some parameters(D, R, $\beta$, $\omega$) used in two-site non-equilibrium adsorption model were obtained from measuring the MTBE concentration in injection-liquid and in effluent and using CXTFIT program. In addition, The characteristics of MTBE transport in the soil was found using BTCs and obtained parameters. Consequently, the advection decreased as the increase of the content of fine particle and organic, while the MTBE transport by advection was enhanced as increasing flow rate and moisture content.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.1
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• pp.147-153
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• 2011

A series of nonequilibrium molecular dynamics(NEMD) simulations are performed to investigate the kinetic energy and velocity distributions of molecules in shock waves. In the simulations, argon molecules are used as a medium gas through which shock waves are propagating. The kinetic energy distribution profiles reveals that as a strong shock wave whose Mach number is 27.1 is applied, 39.6% of argon molecules inside the shock wave have larger kinetic energy than molecular ionization energy. This indicates that an application of a strong shock wave to argon gas can give rise to an intense light. The velocity distribution profiles in z direction along which shock waves propagate clearly represent two Maxwell-Boltzmann distributions of molecular velocities in two equilibrium regions and one bimodal velocity distribution profile that is attributed to a nonequilibrium region. The peak appearing in the directional temperature in z direction is discussed on a basis of the bimodal velocity distribution in the nonequilibrium region.

• Journal of Energy Engineering
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• v.2 no.1
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• pp.54-67
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• 1993

Two turbulent reaction models of the premixed CC1$_4$/CH$_4$/air mixture are successfully incorporated in a 3-dimensional computer program and is applied for Dow Chemical incinerator equipped with two main off-center burners. The first reaction model is fast chemistry model(model 1), in which chemical reaction is governed by the turbulent mixing itself. And the second one is nonequilibrium model(model 2), where the effect of the chemical kinetics due to the presence of CC1$_4$is considered by the incorporation of the burning velocity data of CC1$_4$. The second model not only shows the flame inhibition trend due to the presence CC1$_4$compound, but also predicts qualitatively the vortical stratification of the CC1$_4$concentration appeared experimentally at the kiln exit. Other comparisions of two models are made in detail.

• Journal of the Korean GEO-environmental Society
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• v.16 no.5
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• pp.5-11
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• 2015

The double sheeted permeable reactive barrier containing two different reactive materials can be applied to remediate the groundwater contaminated by nutrients and heavy metals. In this study, in order to evaluate the removal efficiency of contaminants including ammonium, cadmium and phosphate by double layered permeable reactive barrier containing zeolite and steelmaking slag, column tests were performed. In addition, nonequilibrium reaction in column tests was analyzed by two-site nonequilibrium advection-dispersion model. Column test results showed that zeolite is effective for removal of ammonium, while steelmaking slag is effective for removal of phosphate and cadmium. The sequential reaction of zeolite and steelmaking slag gave the better removal efficiency for ammonium.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.1
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• pp.85-96
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• 2003

For a design of rocket engine nozzle, chemical equilibrium analysis which shares the same numerical characteristics with frozen flow analysis can be used as an efficient design tool for predicting maximum thermodynamic performance of the nozzle. 10 this study, a chemical equilibrium flow analysis code was developed for the design of hydrocarbon fueled rocket engines. 10 oder to understand the thermochemical characteristics occurring in a nozzle through the expansion process, such as recombination of chemical components and the accompanying energy recovery, chemical equilibrium flow analysis was carried out for the KSR-III rocket engine nozzles together with frozen flow and non-equilibrium flow analyses. The performance evaluation based on the present KSR-III nozzle flow analyses has provided an understanding of the thermochemical process in the nozzle and additionally, it has confirmed that the newly designed nozzle shape modified to have a reduced exit area ratio is an adequate design for obtaining an increased ground thrust.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.5
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• pp.999-1011
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• 1989

A consideration on the trubulence models for describing the redeveloping turbulent boundary layer beyond separation-reattachment in the flow over a backward-facing step is given through experimental and numerical studies. By considering the blance among the measured values of respective terms in the transport equations for the turbulent kinetic energy and the turbulent shear stress, the recovering process of the redeveloping boundary layer from non-equilibrium to equilibrium has been investigated, which takes place slowly over a substantial distance in the downstream direction. In the numerical study, the standard K-.epsilon. model and the Reynolds stress model have been applied to two kinds of flow regions, one for the entire downstream region after the backward-facing step and another for the downstream region after reattachment. Then the results are compared to a meaningful extent, with the experimental values of the turbulent kinetic energy k, the turbulent energy production term P, the dissipation term K-.epsilon. model, a necessity for a new modelling has been brought forward, which can be also applied to the case of the nonequlibrium turbulent flow.

• The Journal of the Petrological Society of Korea
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• v.13 no.2
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• pp.64-80
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• 2004

The Miocene volcanic rocks in the Eoil Basin, which is one of the pull-apart basins in the southeastern Korean Peninsula, are bimodal in composition: felsic (67.2-70.5wt.% SiO$_2$) and mafic(49.3-55.2wt.% SiO$_2$). The bimodal volcanic activities in the basin appear to be closely associated with the basin development. The volcanic rocks are intercalated with thick Files of sedimentary sequence. They show evidence of magma mixing. which has produced mafic and felsic volcanic rocks. We are able to identify the petrographic characteristics (disequilibrium phenocryst assemblages) of the volcanic rocks that were mixed. In basaltic lava, phenocrysts of olivine and orthopyroxene coexist with corroded quartz phenocryst. Dacitic to rhyolitic welded ash-flow tuff contains phenocrysts of clinopyroxene and orthopyroxene. It suggests that phenocryst disequilibrium have been affected and mixed by magmas, which have different compositions.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.3
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• pp.219-225
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• 2014

In this study, to find the characteristics of the oscillation of a terminating shock wave in a transonic airfoil flow with non-equilibrium condensation, a NACA00-12,14,15 airfoil flow with non-equilibrium condensation is investigated through numerical analysis of TVD scheme. Transonic free stream Mach number of 0.81-0.90 with the variation of stagnation relative humidity and airfoil thickness is tested. For the free stream Mach number 0.87 and attack angle of ${\alpha}=0^{\circ}$, the increase in stagnation relative humidity attenuates the strength of the terminating shock wave and inactivates the oscillation of the terminating shock wave. For the case of $M_{\infty}=0.87$ and ${\phi}_0=60%$, the decreasing rate in the frequency of the shock oscillation caused by non-equilibrium condensation to that of ${\phi}_0=30%$ amounts to 5%. Also, as the stagnation relative humidity gets larger, the maximum coefficient of drag and the difference between the maximum and minimum in $C_D$ become smaller. On the other hand, as the thickness of the airfoil gets larger, the supersonic bubble size becomes bigger and the oscillation of the shock wave becomes higher.