• Journal of Drive and Control
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• v.21 no.2
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• pp.1-7
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• 2024

This paper proposes a novel cooling system for hydrogen fuel cell cooling systems by integrating heat pump technology to enhance operational efficiency. The study analyzed the cooling efficiency of the fuel cell cooling system. With the increasing focus on eco-friendly vehicle technologies to address environmental concerns and global warming, the transportation sector, a major contributor to greenhouse gas emissions, needs technological enhancements for better efficiency. The proposed cooling system was modeled through 1-D simulations. The analysis results of parameters such as thermal balance, temperature, and pressure of each component confirmed the stable operation of the system. By examining variations in the cooling system's flow rate, compressor RPM, and the Coefficient of Performance (COP) based on different refrigerants, initial research was conducted to derive optimal operating conditions and parameter values.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.2
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• pp.10-19
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• 2009

The working of diesel particulate filters(DPF) needs to periodically burn soot that has been accumulated during loading of the DPF. The prediction of the relation between an uniformity of gas velocity and soot regeneration efficiency with simulations helps to make design decisions and to shorten the development process. This work presents a comprehensive combined 'DOC+CDPF' model approach. All relevant behaviors of flow fluid are studied in a 3D model. The obtained flow fields in the front of DPF is used for 1D simulation for the prediction of the thermal behavior and regeneration efficiency of CDPF. Validation of the present simulation are performed for the axial and radial direction temperature profile and shows goods agreement with experimental data. The coupled simulation of 3D and 1D shows their impact on the overall regeneration efficiency. It is found that the flow non-uniformity may cause severe radial temperature gradient, resulting in degrading regeneration efficiency.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.9
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• pp.1803-1810
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• 2009

This paper designed IQ imbalance estimator and compensator to cancel the IQ imbalance error in DVB-T system using OFDM by Matlab. Among Matlab model, we designed and implemented IQ imbalance estimator and compensator by System Generator of Xilinx and Matlab model compared with Xilinx System Generator Model for FPGA implementation. As a result of simulation, we confirmed that both model estimated and compensated IQ imbalance error very well. Also, we verified the performance through hardware co-simulation, timing analysis and resource estimation with Xilinx Spartan3 xc3s1000 fg676-4 target Device.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.2
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• pp.8-17
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• 2008

This paper presents the Matlab/Simulink-based software-in-the-loop simulation(SILS) environment which is the co-simulator for temporal and functional simulations of control systems. The temporal behavior of a control system is strongly dependent on the implemented software and hardware such as the real-time operating system, the target CPU, and the communication protocol. The proposed SILS abstracts the system with tasks, task executions, real-time schedulers, and real-time networks close to the implementation. Methods to realize these components in graphical block representations are investigated with Matlab/Simulink, which is most commonly used tool for designing and simulating control algorithms in control engineering. In order to achieve a seamless development from SILS to rapid control prototyping (RCP), the SILS block-set is designed to support automatic code generation without tool changes and block modifications.

• 한국연소학회:학술대회논문집
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• 2012.11a
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• pp.215-218
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• 2012

In this study, syngas laminar burning velocities with various hydrogen contents were studied using both experimental measurements and kinetic simulations. The laminar burning velocities were measured by the angle method of Bunsen flame configuration and the numerical calculations including burning velocities were made using CHEMKIN Package with USC-Mech II. A large range of syngas mixture compositions such as 10:90%, 25:75%, 50:50%, 75:25% and equivalence ratio from lean condition of 0.5 to rich condition of 5.0 have been conducted. The experimental results of burning velocity were in good agreement with previous other research data and numerical simulation. Also, it was shown that the experimental measurements of laminar burning velocity linearly increased with the increasing of $H_2$ content although the flame speed of hydrogen is faster about ten times than carbon monoxide. This phenomenon is attributed to the rapid production of the hydrogen related radicals such as H and OH at the early stage of combustion, which is confirmed the linear increasing of radical concentrations on kinetic simulation.

• Journal of Mechanical Science and Technology
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• v.15 no.12
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• pp.1768-1774
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• 2001

Drifting Cups on a Meandering Stream (Kyokusui-no-En) is a Poetry Party that had its origin In ancient China, and was introduced to Japan passing through Korea. The flow of the meandering stream was made clear using the flow visualization techniques, surface floating method, PTV and the numerical simulation. At the same time, the motions of floating cup, the floating speed, relating speed and the trajectory of the cup were also analysed by using an originally developed image processing technique. Based on these researches, the model channel was considered. To make this party interesting the channel must has the characteristic that the drifting cups take the random pass and stagnant at the unexpected place. This model channel is satisfied with these conditions and the fluid mechanics consideration is performed on the both points of the experimental visualization and numerical simulation.

• KEPCO Journal on Electric Power and Energy
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• v.3 no.2
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• pp.141-146
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• 2017

In this work, a simulation study on net 500 MW class of Poly-Generation was conducted for the retrofit of an aged natural gas combined cycle. An entrained gasifier which has a capacity of maximum $260,000Nm^3/h$, 50 MW class of a Polymer Electrolyte Membrane Fuel Cell, and H-class Gas Turbine were selected as key processes. After unit design for those employed processes was set up and combined, the simulation was carried out with Gate-Cycle software (Ver. 6.0) for two cases. The selected cases are a retrofit type (Poly-Gen 1) and a new type (Poly-Gen 2). It was found that the efficiency of the retrofit case is 2.7% lower than that of the new case.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2012.04a
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• pp.266-269
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• 2012

화재 시뮬레이션을 이용하면, 건축물에서 화재가 발생하는 경우 건물에 설치된 감지 시스템 및 자동식 소화설비 등의 작동 여부에 따라 건물 내부의 온도 변화, 산소 및 일산화탄소 농도 변화, 연기유동 현상 등 화재 안전에 관련된 요소를 확인, 분석이 가능하기 때문에 건물의 화재 안전성을 검증하는데 활용할 수 있고 방재시스템 설계 조건을 변경하여 반복 시뮬레이션을 실시함으로써 보다 효율성이 높은 방재 시스템을 설계 및 채택할 수 있다. 또한 화재 시뮬레이션 결과를 감안하여 유사시 효과적으로 대응할 수 있도록 방재계획을 수립할 수 있고, 건축물의 구조, 내장재 및 수용품에 대한 설계, 배치 등에 사용할 수 있으며, 화재사고조사 및 원인 규명에도 활용할 수 있는 등 화재 시뮬레이션의 활용분야는 광범위하다. 최근 국내에도 화재로 인한 인적/물적 피해와 화재 안전 설계에 대한 관심증가로 화재 모델에 대한 많은 연구가 이루어지고 있다. 그러나 대부분의 연구가 시뮬레이션을 이용한 결과 분석에 치중되어있고 화재 시뮬레이션에 관한 특성 연구 및 개발은 거의 이루어지지 않고 있다. 본 자료는 국내에서 화재 시뮬레이션 코드로 많이 알려지지 않았으며, 유럽에서 개발된 SOFIE(Simulation of Fire in enclosures)에 대해서 기초적인 연구를 수행하였으며, SOFIE에 대한 특정 문제나 평가 부분은 다루지 아니하였다.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.138-138
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• 2011

GTL(Gas to Liquid) 합성유 생산 공정은 크게 합성가스 개질공정(reformer), FT 반응공정, upgrading 공정으로 구성된다. 본 연구에서는 FT 반응기에 유입되는 합성가스의 생산공정인 개질공정 최적화 시뮬레이션을 수행하였다. 기존에 HYSYS 공정 모사 tool로 구현한 개질공정 모델에 dynamic simulation을 적용하여 공정 운전 시간 변화에 따른 온도/압력/조성의 일정범위 별 생산 가스의 성분비를 모사하고자 한다. Dynamic 공정 시뮬레이션은 모사 대상 공정의 운전 시간 별 결과값 변화를 산출할 수 있는 방법으로 기존 정상상태(steady-state) 시뮬레이션에 비해 현실 공정의 운전 변수를 보다 더 정확하게 반영할 수 있는 장점이 있다. 본 시뮬레이션은 1bpd급 GTL 파일럿 플랜트의 설계 자료를 근거로 수행되었으며, 향후 운전 데이터를 feedback하여 최적의 운전 매뉴얼 도출자료로 활용코자 한다. 아울러, 다음의 시간 변화별 모사 결과 데이터들을 산출하고 공정의 최적운전 조건을 분석하고자 한다. - 시간에 따른 공정의 온도/압력 변화, 이에 연동되는 반응기 출구의 1) $H_2$/CO 비율, 2) $CH_4$ conversion, 3) $CO_2$ conversion 본 연구의 결과 데이터를 1bpd급 GTL 플랜트 내 합성가스 개질공정의 운전조건 최적화에 적용코자 하며, 이는 개질반응기의 안정적인 연속운전을 통한 GTL 통합공정의 운전 효율향상에 기여 가능하리라 기대된다. 향후 개질공정의 후단공정인 FT 합성공정 시뮬레이션 과업과 연계하여 GTL 통합공정 시뮬레이션 및 최적화에 따른 실증 규모의 스케일업 기반 데이터를 마련할 수 있을 것이다.

• Water Engineering Research
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• v.1 no.4
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• pp.267-277
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• 2000

This study reports an examination of the sensitivity of water resources in the Keum River basin to climate change. Assuming a doubling in $CO_2$ concentrations, a cooperative study provided four climate change scenarios for this study, which have been translated into temperature and precipitation scenarios on a basin scale. The study utilized these temperature and precipitation data for each climate change scenario as inputs to the NWS-PC model to generate the corresponding streamflow scenario over the Keum River basin. A reservoir simulation model for the Dae-Chung Dam in the Keum River basin has been developed with an object-oriented simulation environment, STELLA. For each streamflow scenario, the performance of the reservoir was assessed in terms of reliability, resiliency, and vulnerability. Although the simulation results are heavily dependent on the choice of the climate change scenarios, the following conclusions can be clearly concluded: (1) the future streamflow over the Dae-Chung Dam tends to decease during the dry period, which seriously increases competitive water use issues and (2) flood control issues predominate under the $2CO_2$-High case.