회원작품 - 마실

김대희,Kim, Daehee 대한건축사협회 2018 建築士 Vol.592 No.-

덕트 버너의 추가에 따른 HRSG 내 화염 복사 열전달 산정방안에 대한 연구

김대희(Daehee Kim),김승진(Seungjin Kim),최상민(Sangmin Choi),이봉재(Bongjae Lee),김진일(Jinil Kim) 한국연소학회 2012 KOSCOSYMPOSIUM논문집 Vol.- No.44

Analysis method for the radiation heat transfer from the duct burner flame to the heat exchanger in a Heat Recovery Steam Generator (HRSG) was presented to supplement the existing thermal design process. Flame on a burner and a heat exchanger were postulated as imaginary planes and flame temperature, surface and emissivity was simplified in a aspect of engineering approach. The calculated local flame radiative heat flux on the heating surface was compared with the heat flux of 3-atomic gas radiation and convection.

계층적 영역분포분석을 사용한 얼굴 포즈 인식

김대희(Daehee Kim),이승원(Seungwon Lee),백준기(Joonki Paik) 대한전자공학회 2010 대한전자공학회 학술대회 Vol.2010 No.6

지속가능발전을 위한 전남 환경교육 활성화 방안

김대희(Daehee Kim),안삼영(Samyoung Ahn),이기환(Keyhwan Lee),신효연(Hyoyeon Shin),강흥순(Heungsoon Kang) 한국환경교육학회 2018 環境 敎育 Vol.31 No.4

2008년 환경교육진흥법에 의거 제 2기 전라남도 환경교육발전계획이 수립, 추진되어야 하는 실정이다. 이를 위해 이 연구는 전남의 학교 및 사회 환경교육의 실태 분석, 기관 조사, 제1기 환경교육 발전계획 추진 실적 평가 등을 실시하였다. 이를 바탕으로 전남의 지속가능발전을 위한 환경교육 활성화 안을 구상하였다. 활성화 안에 대한 타당성과 적합성을 높이기 위하여 전남지역의 환경교육 전문가 12명으로부터 7월부터 11월 초순까지 3회의 자문을 받아 보완하였으며, 이를 환경교육 단체 및 시민을 대상으로 2018년 11월 말에 공청회를 실시하였다. 또한 연구의 계획, 진척 내용 등에 대하여 도청 및 도 환경교육센터의 관계자 회의를 거쳐 전라남도의 지속가능발전을 위한 환경교육활성화 비전, 발전 방안, 시책들을 수립하게 되었다. 전라남도의 환경교육 활성화 비전은 ‘지역과 함께하는 환경교육 특성화, 활성화’로 설정하였다. 그리고 학교 환경교육 활성화 방안 4개와 시책 5개, 사회 환경교육 활성화 방안 5개와 시책 6개, 환경교육 활성화 기반구축 방안 5개와 시책 5개를 설정하였다. Based on the Environmental Education Promotion Act enacted in 2008, the Second Policy Plan for promoting environmental education in Jeollanam province is to be developed in 2018. To this end, we analyzed the current state of environmental education in schools and in the society at large, conducted surveys on environmental organizations, and assessed the First Environmental Education Policy Plan (in place since 2013). These formed the basis for the strategies we recommend to vitalize environmental education for sustainable development in Jeollanam province. In order to ensure the feasibility and appropriateness of these plans, three rounds of consultations with 12 experts and a public hearing were carried out. A meeting with responsible public officials and leadership in environmental education centers were also convened to develop the vision, strategies and future plans. The resultant vision is “locally specialized and vitalized environmental education” and propose 5 programs to promote environmental education in schools, 6 programs to promote environmental education within the broader public, and 5 programs to establish the basis for invigorating environmental education.

단입자 촤 burnout 계산을 통한 촤 연소율에 미치는 CO₂ 가스화 반응성에 관한 연구

김대희(Daehee Kim),최상민(Sangmin Choi) 한국연소학회 2011 KOSCOSYMPOSIUM논문집 Vol.- No.42

A simple one-dimensional calculation of char burnout was conducted to show the effect of CO₂ gasification reactivity on the total char burnout under oxy-combustion environment. A global char burnout model considering the influence of pore diffusion, chemical reaction and mass transfer and a double-film model was used. The apparent activation energy for char-CO₂ reaction was determined reasonably from the literature and the apparent pre-exponential factor was changed based on the relative rate of CO₂ gasification to oxidation. When the char-CO₂ reaction was included in the calculation of 1600K condition, the char burnout was improved by 1.1% in the case of low reactivity and by 9.1% in the case of high reactivity, relative to the char-O₂ only case. Also, this CO₂ gasification effect on the char burnout was increased at high temperature because of the activation of the char-CO₂ reaction.

Inter-Domain Curriculum Learning for Domain Generalization

Daehee Kim(김대희),Youngjun Yoo(유영준),Inkyung Kim(김인경),Jaekoo Lee(이재구) 한국통신학회 2021 한국통신학회 학술대회논문집 Vol.2021 No.2

Despite the rapid advancements in deep learning, the appropriate performance is not guaranteed under domain-shift. This problem has been addressed through domain generalization (DG). In DG, decreasing the required computation is difficult to achieve because training should be performed multiple times to infer the average performance owing to the large deviation of performance. We propose inter-domain curriculum learning, a method that sequentially transforms easy-to-learn domain data to difficult-to-learn domain data. Quantitative experiments have demonstrated that the average performance increased by 1.08 points and the performance deviation is reduced. Moreover, the research cycle can be accelerated by reducing 16.7% of the computation.

상용 CFD 코드에서 사용되는 촤 반응속도 모델에 대한 이해

김대희(Daehee Kim),최상민(Sangmin Choi) 한국연소학회 2013 KOSCOSYMPOSIUM논문집 Vol.- No.46

Commercial computational fluid dynamics (CFD) codes traditionally rely on the computational efficiency of the simplified single-film apparent char kinetic model to predict char particle temperatures and char conversion rates in pulverized coal boilers. The aim of this study is to evaluate the reliability of the single-film apparent kinetic model and to suggest the importance of proper use of this model. For this, a parametric study was conducted with a consideration of main parameters such as Stefan flow, product species, particle evolution, and kinetic parameters.

덕트 버너 추가에 따른 수직형 HRSG 내 화염 복사 열전달의 영향에 관한 연구

김대희(Daehee Kim),김승진(Seungjin Kim),최상민(Sangmin Choi),이봉재(Bong Jae Lee),김진일(Jinil Kim) 대한기계학회 2013 大韓機械學會論文集B Vol.37 No.2

본 연구에서는 덕트 버너를 추가적으로 사용하는 수직형 배열회수 보일러(HRSG)에서 발생하게 되는 화염에 의한 전열면으로의 화염 복사 열전달에 의한 영향을 살펴보기 위한 해석 기법을 마련하였다. 덕트 버너 화염과 전열면은 가상의 평면으로 가정하였고, 화염 온도, 면적 및 방사율 입력정보는 간략화 하였다. 덕트버너 설치 위치 및 연료를 달리한 3 가지 해석 case 가 고려되었으며 계산된 화염 복사열전달률과 열유속은 삼원자 가스 복사 및 대류 열전달과 비교되었다. 모든 해석 case 에서 삼원자 가스 복사 열전달에 의한 영향은 미미하였고, 전열면에서 대류 열전달 대비 화염 복사 열전달률은 8~41%인 것으로 나타났다. 이 연구에서 얻은 중요한 사실은 화염 복사가 집중되는 전열면의 중앙부분에서 국부적인 열유속은 화염 복사에 의해 완전히 지배된다는 것이다. A method was developed for analyzing the radiation heat transfer from the duct burner flame to the heat exchanger in a heat recovery steam generator (HRSG) in order to supplement the existing thermal design process. The burner flame and the heat exchanger were considered to be imaginary planes, and the flame temperature, surface, and emissivity were simplified using an engineering approach. Three analysis cases in which the duct burner position and fuel were changed were considered. The calculated flame radiative heat transfer and local flux on the heating surface were compared with those of 3-atomic gas radiation and convection. In all analysis cases, heat transfer by 3-atomic gas radiation was very small. The ratio of the flame radiative heat transfer to the convection heat transfer on the heating surface was estimated to be as high as 8?41%. Moreover, the local heat flux on the heating surface centerline was dominated by flame radiative heat flux.

연소중 미분탄의 발광 분석 및 입자 채집 관찰

김대희(Daehee Kim),최상민(Sangmin Choi) 한국연소학회 2010 한국연소학회지 Vol.15 No.2

Combustion behavior of pulverized coal particles in a post-combustion gas reactor was investigated. Radiation emission from coal particles were analyzed by direct photograph and CH<SUP>*</SUP> radical chemiluminescence intensity. Coal particles were sampled during the combustion and were observed by scanning electron microscopy (SEM) and cross section micrograpy technique. Two coal types(one bituminous and one subbituminous coals typically used in the Korean power plants) were tested at typical combustion environment. Gas flow conditions were controlled to represent temperature and oxygen concentration. Experimental data were discussed along with conceptual descriptions of pulverized coal combustion, where particle heat-up, release and combustion of volatiles, and char combustion were sequentially progressed.

순산소 미분탄 연소 CFD 연구에 사용되는 촤 반응속도 모델의 적절한 사용에 대한 연구

김대희(Daehee Kim),최상민(Sangmin Choi) 한국연소학회 2012 KOSCOSYMPOSIUM논문집 Vol.- No.45

Many computational fluid dynamic (CFD) simulations have treated the coal kinetics poorly due to large physical domain sizes and high computational complexity, particularly for the recent oxy-coal boilers. Furthermore, some modelers’ lack of understanding of the kinetic rate model seems to worsen the simulation accuracy. This study is to suggest the importance of proper use of single-film global kinetic model generally used in CFD code to describe the oxy-fuel combustion of coal char through simple char burnout calculation.