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오픈소스 OpenFOAM을 이용한 실제 금속폼의 유동 및 열전달 특성 해석
오경택(KyungTaek Oh),김군홍(GunHong Kim) 한국전산유체공학회 2014 한국전산유체공학회 학술대회논문집 Vol.2014 No.5
Nowadays, the need for developing more effective heat exchange technologies and innovative materials is well recongnized. metal foams have a great potential for enhancing the thermal efficiency of heat transfer devices, while alllowing for the use of smaller and lighter equipments. However it is necessary to compromise between the augmented heat transfer rate and the increased pressure drop induced by the tortuous flow passages for practical applications. This study is mainly motivated to analyze the characteristics of flow and conjugate heat transfer in metal foams using opensource OpenFOAM. This paper presents a numerical analysis of flow and conjugate heat transfer through seven different metal foam. pressure drop, effective thermal conductive coefficient and effective convective coefficient. increase with decreasing porosity. However, when Reynolds number has been increased above a certain value, effective convective coefficient and Nusselt number declined increase rate. this study result can be extraxted for the detailed mechanism of the flow and heat transfer in such complicated geometries.
오픈 소스 OpenFOAM을 이용한 정상상태 난류 연소장에 대한 해석적 연구
오경택(Kyungtaek Oh),김군홍(Gunhong Kim) 한국연소학회 2013 KOSCOSYMPOSIUM논문집 Vol.2013 No.12
This study is mainly motivated to develop reliable simulator to predict the Steady turbulent combustion using open source OpenFoAM. In order to validate developed OpenFOAM code, CFD modeling study has been performed for two different cases. One is a Piloted methane-air jet flame. the other is a lab-scale 0.8 MW oxy-natural gas flame furnace, in two cases results, predicted relatively chemical species and temperature have good agreement with experimental data, after this code will implement variety of turbulent combustion model and radiation model for more accurate results.
오경택(Oh Kyungtaek) 한국정치학회 1999 한국정치학회보 Vol.33 No.2
지구온난화 레짐형성에 관한 미국정부의 정책결정과정에는 환경운동단체와 업계의 영향력이 경쟁적으로 작용하여, 미국이 협조적이며 일관된 정책을 펴기 어려웠다. 부시행정부는 주로 업계의 이해관계를 반영하여 온실가스 의무감축에 적극 반대하였으며, 클린턴 행정부도 초기 몇 년 간은 주로 의회에 반영된 산업체의 영향력으로 소극적 입장을 유지했다. 그러나 공화당의 양원 장악 후 오히려 활성화 된 환경운동권의 활동은 1996년 제2차 당사국총회에서 미국이 처음으로 의무감축을 약속하도록 하는데 중요한 요인이 되었다. 그러나 업계의 영향력은 지속적으로 의회에 효력을 발휘해 미국을 비롯한 선진국들의 온실가스 의무감축을 약속한 1997년 쿄토의정서가 아직 미 의회에서 비준을 받지 못하고 있다. 이와 같이 정책결정과정에 영향을 행사하는 환경단체나 업계의 활동은 내적역량의 변화와 외적 조건에 따라 실효성이 달라지며, 영향력 행사활동으로 볼 수 있는 것들은 의회ㆍ행정부에 대한 로비, 선거활동, 행정부에 직접참여, 대중홍보, 대중교육, 항의, 시위 등이다.
IGCC 가스터빈 운전조건에서의 석탄가스 층류화염속도에 대한 기초연구
이정원(Jeongwon Lee),오경택(Kyungtaek Oh),김용모(Yongmo Kim) 한국연소학회 2011 한국연소학회지 Vol.16 No.4
Coal-derived syngas has been utilized by main fuel at IGCC power plant. Research efforts for investigating the characteristics of premixed and nonpremixed flames at gas-turbine condition have been conducted. The present study has been mainly motivated to evaluate the capability of the detailed chemical kinetics to predict the syngas laminar flame speed. Special emphasis is given to the effects of pressure, temperature, syngas composition, and dilution level on the characteristics of premixed and nonpremixed flames. The predicative capability of a number of detailed mechanism for laminar flame speed is compared to experimental data. From these results, detailed kinetics of Davis et al. and Li et al. have the best conformity with the experiments in the all the case of parametric studies.
김주연(Jooyeon Kim),오경택(Kyungtaek Oh),차정권(Jeongkwon Cha) 한국자동차공학회 2021 한국자동차공학회 부문종합 학술대회 Vol.2021 No.6
As for emission regulations and standards for fuel efficiency for cars, they are becoming stricter year by year and the preference for low fuel efficiency, or efficient vehicles, is increasing. One of a solution to adopt Continuously Variable Transmission(CVT). CVT system is able to shift infinitely, it is suitable in various driving conditions. However, CVTs have one disadvantage. There is a noise problem caused by the vibration of the chain. Improving this problem, we have to develop a simulation model to predict system noise for CVT system. In this paper, we explain a method of CVT system modeling by using DAFUL, and compared simulation and experiment NVH results.