• Korean Chemical Engineering Research
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• v.61 no.4
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• pp.550-554
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• 2023

Fossil energy sources are limited in their sustainable use and expansion due to global warming caused by carbon dioxide emissions. Hydrogen is considered as a promising alternative to traditional fossil fuels. To ensure the stable long-term storage, it is necessary to accurately predict its thermodynamic properties at cryogenic temperatures. Therefore, this study aimed to investigate thermodynamic properties, such as saturated vapor pressure and density, enthalpy, and entropy of liquid and gas, using cubic equations of state that demonstrate relatively simple relationships. Among the three types of equations of state (Redlich-Kwong (RK), Soave-Redlich-Kwong (SRK), and Peng-Robinson (PR)), the SRK model exhibited relatively accurate prediction results for various physical properties.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.05a
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• pp.166-168
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• 2018

해기사의 행동오류는 해양사고를 야기하는 최종 결과물이다. 해기사의 행동오류는 SRK(Skill, Rule, Knowledge) 행동이론을 통해서 규명할 수 있고, 이러한 행동오류는 해양사고 기록을 통해서 식별할 수 있다. 본 발표의 목적은 과거 해양사고 기록을 토대로 해기사들의 다양한 행동오류와 이들 행동오류로 인하여 발생한 해양사고를 연계하여 해기사들의 행도오류를 평가하기 위한 방법과 현재까지의 결과를 소개하는데 있다. 라스무센이 제한한 행동이론에 해양사고 기록을 적용하여 해양사고 발생 당시의 해기사들의 행동오류를 식별할 수 있었다. 식별한 변수를 이용하여 해기사들의 행동오류를 추정한 결과, 사고원인과 결과 및 행동오류 사이에 강한 상관관계를 나타냈다. 추후, HMM(Hidden Markov Model)을 이용한 예측 기법을 적용하여 행동오류에 따른 해양사고 예방 방안을 제안할 예정이다.

• Journal of Navigation and Port Research
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• v.40 no.1
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• pp.27-34
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• 2016

For the prevention of marine casualties, international bodies have mainly focused on strengthening ship's stability and design, maritime education and training, and improving maritime traffic environment. Statistics analysis on marine casualties showed that most of casualties occurred in coastal waters, especially by human elements. In order to review the conformity of existing prevention measures with the result of the statistics analysis, the IMO's SHELL model was applied to the established measures. As a result, ergonomic approaches were needed for the prevention of human errors in coastal waters, so that the priority should be given to the interface between ship's operator and navigational environment. For this study, Rasmussen's SRK pyramid, which showed decision making mechanism of human, and the US Coast Guard's investigation manual on marine casualties concerning the collapse of safe maritime transportation system were reviewed, and the merits and demerits within the risk assessment tools such as IWRAP, PAWSA, ES model, PARK model, and NURI model were also studied. Although the effectiveness of the existing risk assessment models was proved in ports and approaching channels, it is concluded that the need of new models for converting Korean seafarers' qualitative risk to quantitative risk was proposed so as to print hazard maps which make seafarers instinctively recognize comparative hazard levels of coastal waters.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• v.y2005m4
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• pp.183-188
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• 2005

This study targets to investigate thermal wave transfer in a droplet strongly coupled with acoustic pressure and its effects on combustion response. The one-dimensional vaporization model uses SRK equation of state and flash calculation method to obtain more accurate thermophysical properties and compute vapor-liquid equilibrium. Calculations of an n-pentane droplet exposed into a perturbing nitrogen gas is carried out in terms of different ambient gas pressures and wave frequencies. The thermal wave is transferred more effectively at lower frequencies, which results in the decrease in the amplitude of the response.

• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.3
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• pp.21-29
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• 2013

Turbulent flow and thermal fields of gaseous hydrogen/liquid oxygen flames at supercritical pressure are investigated by turbulence models. The modified Soave-Redlich-Kwong (SRK) EOS is implemented into the flamelet model to realize real-fluid combustions. For supercritical fluid flows, the modified pressure-velocity-density coupling are introduced. Based on the algorithm, the relative performance of six convection schemes and the predictions of four turbulence models are compared. The selected turbulence models are needed to be modified to consider various characteristics of real-fluid combustions.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.85-88
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• 2010

This study has been mainly motivated to numerically model the supercritical mixing and combustion processes encountered in the liquid propellant rocket engines. In the present approach, turbulence is represented by the extended $k-{\varepsilon}$ turbulence model. To account for the real fluid effects, the propellant mixture properties are calculated by using SRK (Souve-Redlich-Kwong) equation of state. In order to realistically represent the turbulence-chemistry interaction in the turbulent nonpremixed flames, the flamelet approach based on the real fluid flamelet library has been adopted. Based on numerical results, the detailed discussions are made for the real fluid effects and the precise structure of gaseous methane/liquid oxygen coaxial jet flame.

• Transactions of the Korean hydrogen and new energy society
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• v.31 no.2
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• pp.184-193
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• 2020

One of the technical methods to increase the volumetric energy density of hydrogen is to pressurize the gaseous hydrogen and then contain it in a rigid vessel. Especially for automotive systems, the compressed hydrogen storage can be found in cars as well as at refueling stations. During the charging the pressurized hydrogen into a vessel, the temperature increases with the amount of stored hydrogen in the vessel. The temperature of the vessel should be controlled to be less than a limitation for ensure stability of material. Therefore, the accurate estimation of temperature is of significance for safely storing the hydrogen. In this work, three well-known cubic equations of state (EOSs) were adopted to examine the accuracy in regenerating thermodynamic properties of hydrogen within the temperature and pressure ranges for the compressed hydrogen storage. The formulations representing molar volume, internal energy, enthalpy, and entropy were derived for Redlich-Kwong (RK), Soave-Redlioch-Kwong (SRK), and Peng-Robinson (PR) EOSs. The calculated results using the EOSs were compared with literature data given by NIST. It was revealed that the accuracies of RK and SRK EOSs were satisfactorily compatible and better than the results by PR EOS.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.31-34
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• 2012

Numerical simulations of the steady and unsteady state were conducted for a coaxial swirl injector with Kerosene fuel. Non-premixed equilibrium model based on chemical equilibrium assumption was used as turbulence-chemistry interaction model. As an equations of state, SRK(Soave-Redlich-Kwong) EOS was applied to deal with the behavior of real fluid in a high pressure condition. Through the steady and unsteady computations, mean values of steady and time-averaged unsteady state were compared on the temperature and OH mass fraction and it was shown that the flame structure of steady state was different to that of time-averaged unsteady state.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2017.11a
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• pp.256-258
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• 2017

사용자 인터페이스를 설계하는 방법의 하나로써 생태적 인터페이스 설계(Ecological Interface Design) 방법이 제안되었고, 다양한 분야에서 이 방법을 활용하여 인터페이스를 설계하고 있다. 그러나 해양분야에서는 EID 사례가 많지 않았다. 따라서 본 연구에서는 생태적 인터페이스 설계의 절차를 살펴보고, 해양분야에서 수행한 몇 가지 EID의 사례를 소개하였다. 마지막으로 선박충돌을 예방하기 위한 EID의 가능성에 대해 제시하였다.

• Journal of the Korean Institute of Gas
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• v.10 no.2 s.31
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• pp.22-26
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• 2006

In this study, modeling and simulation works using Aspen Plus were carried out for DME separation and purification process of pilot plant for the daily production of 50 kg of DME. For modeling of the entire DME separation unit, NRTL liquid activity coefficient model was used for the prediction of liquid phase non-idealities, Henry's law option was also used for the estimation of solubilities of light gases in solvents and SRK equation of state model was utilized for the description of vapor phase non-idealities. DME having over 98 wt% purity was obtained as a side distillate product in a DME purification column.