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CFD를 활용한 선박고온도차발전용 WHRU의 열유동 해석에 관한 연구
황대중,박상균,지재훈,방은신,오철,Whang, Dae-jung,Park, Sang-kyun,Jee, Jae-hoon,Bang, Eun-shin,Oh, Cheol 해양환경안전학회 2021 해양환경안전학회지 Vol.27 No.5
IMO에서는 선박으로부터 온실가스 감축을 위해 선박의 에너지효율 증진에 관한 논의를 진행하고 있다. 현재, 선박으로부터 발생되는 폐열을 이용한 ORC 발전 시스템을 적용함으로써 선박으로부터 높은 에너지 변환 효율을 기대할 수 있다. 이 기술은 물보다 더 낮은 온도 범위에서 증발하는 프레온 또는 탄화수소 계통의 유기 매체를 작동 유체로 사용한다. 이를 통해 상대적으로 낮은 저온에서 증기(기체)를 생성 및 동력을 발생시킬 수 있다. 본 연구에서는 유기 랭킨 사이클인 ORC 발전 시스템에서 냉매와 폐열 사이 열·유동해석(Analysis of Heat flow)을 3D 시뮬레이션 기법을 이용하여 구조물의 내·외부에 흐르는 유체가 온도 변화, 속도 변화, 압력 변화 및 질량 변화를 통해서 구조물에 어떤 영향을 미치는지를 분석하고자 하며, 동 연구는 이 기법을 이용하여 ORC 발전 시스템에서 냉매와 선박 주기관의 배기가스로부터 일어나는 열교환기의 열전달을 해석하였다. The IMO (International Maritime Organization) is discussing the improvement of energy ef iciency of ships in order to reduce greenhouse gas emissions from ships. Currently, by applying an ORC power generation system using waste heat generated from ships, high energy conversion efficiency can be expected from ships. This technology uses an organic medium based on Freon or hydrocarbons as the working fluid, which evaporates at a lower temperature range than water. Through this, it is possible to generate steam (gas) and generate power at a low and low temperature relatively. In this study, the analysis of heat flow between the refrigerant and waste heat in the ORC power generation system, which is an organic Rankine cycle, is analyzed using 3D simulation techniques to determine the temperature change, velocity change, pressure change, and mass change of the fluid flowing of the WHRU (Waste Heat Recovery Unit) inside and the outside the structure. The purpose of this study is to analyze how the mass change affects the structure, and this study analyzed the heat transfer of the heat exchanger from the refrigerant and the exhaust gas of the ship's main engine in the ORC power generation system using this technique.
황대중 ( Dae-jung Hwang ),오철 ( Cheol Oh ),박상균 ( Sang-kyun Park ),지재훈 ( Jae-hoon Jee ),방은신 ( Eun-shin Bang ),이병길 ( Byeong-gil Lee ) 한국신·재생에너지학회 2022 신재생에너지 Vol.18 No.2
This study was aimed at designing a condenser, as a component of the organic Rankine cycle system for ships. The condenser was manufactured through press molding to achieve a bent shape to enhance the heat transfer performance, considering the shape of the heat transfer plate used in a brazing plate heat exchanger. The heat transfer plate was made of copper-nickel alloy. The required heat transfer rate for the condenser was 110 kW, and the maximum number of layers was set as 25, considering the characteristics of high-temperature brazing. Computational fluid dynamics techniques were used to perform the thermal fluid analysis, based on the ANSYS CFX (v.18.1) commercial program. The heat transfer rate of the condenser was 4.96 kW for one layer (width and length of 0.224 and 0.7 m, respectively) of the heat transfer exchanger. The fin efficiency pertaining to the heat transfer plate was approximately 20%. The heat flow analysis for one layer of the heat exchanger plate indicated that the condenser with 25 layers of heat transfer plates could achieve a heat transfer rate of 110 kW.
Marfan 증후군에 동반되어 좌우관상동맥확장을 보인 1 예
심대중(Dae Jung Shim),김범수(Bum Soo Kim),강진호(Jin Ho Kang),이만호(Man Ho Lee),박정로(Jeong Ro Park),이상종(Sang Jong Lee),오태윤(Tae Un Oh),장운하(Oun Ha Jang),김명숙(Myung Sook Kim) 대한내과학회 1998 대한내과학회지 Vol.54 No.6
Marfan`s syndrome is a an autosomal dominant disorder of connective tissue that is characterized by ocular, skeletal, and cardiovascular manifestation. It is estimated to have a prevalence of 4-6 per 10,000 people, and at least 25 percent of the cases occur in the absence of a family history. Coronary artery ectasia is a diffuse abnormality of the vessel wall, which has been reported in associated with coronary atherosclerosis, infectious process, congenital heart lesion, syphilis, Ehlers-Danlos syndrome. We reported a case of 25-year-old male who presented with Marfan`s syndrome associated with dissecting ascending arotic aneurysm and diffuse dilatated coronary artery ectasia. Coronary angiographic study demonstrated the diffusely dilatated coronary artery ectasia.
김상훈(Sang Hoon Kim),심대중(Dae Jung Shim),서원태(Won Tae Seo),임시영(Si Young Lim),이승세(Seung Sei Lee),국신호(Shin Ho Kook),금주섭(Joo Seob Keum),오태윤(Tae Yoon Oh),장운하(Woon Ha Chang) 대한내과학회 1999 대한내과학회지 Vol.57 No.1
Epithelioid hemangioendothelioma(EH) is a rare vascular tumor of low-grade malignancy. It was previously described as intravascular bronchioloalveolar tumor (IVBAT). But electron microscopic study and immunohistochemical staining results have proved endothelial origin. Patients are usually asymptomatic and the tumors are found incidentally on routine chest X-rays. Most patients show a slowly progressive clinical course, even though some patients occasionally die as results of respiratory failure or extrathoracic complications. Confirmative diagnosis is made through thoracoscopic or open-lung biopsy. There is still no effective therapeutic modality for pulmonary EH. We have experienced a 55-year-old woman whose simple chest x-ray film revealed bilateral multiple small nodules. The nodules were histopathologically and immunohistochemically diagnosed as primary epithelioid hemangioendothelioma of the lung. The possibility of metastatic disease was excluded thorough clinical, laboratory and radiological studies. Comparison of radiographic chest film taken 3 years ago showed no significant progression of the pulmonary nodular lesions. Conservative management was instituted and careful 4 months follow-up showed no significant changes.
지역문제 해결을 위한 도시재생사업의 협력적 거버넌스 구축 및 참여주체별 역할에 관한 연구 - 서울 동북4구 사례를 중심으로
윤병훈(Yun, Byung-Hun),정선철(Jeong, Sun-Cheol),오대중(Oh, Dae-Jung),이삼수(Lee, Sam-Su) 한국도시설계학회 2020 도시설계 : 한국도시설계학회지 Vol.21 No.6
도시는 주변지역과의 관계를 통해 성장하고 쇠퇴하는 유기체와 같은 속성을 가지고 있다. 즉 지역에서 발생하는 문제도 지역 고유의 것이 아니고, 주변 지역으로부터 영향을 받는 경우가 많다. 본 연구는 지역문제를 이웃 지자체간 협력을 통해 해결하고 있는 동북4구 사례를 통해, 대내외적 여건 변화에 따른 도시재생의 방향과 전략을 제시하는 것이 목적이다. 기존문헌, 행정문서를 활용하여 동북4구의 현황과 협력사업을 분석해 도출한 결과를 정리하면 동북4구는 역사 · 문화 자산을 공유하며 유사한 지역적 특성을 가지고, 도시재생에서 활용할 수 있는 잠재력을 보유하고 있지만 서울의 대표적 베드타운으로 일자리 기반이 취약하다. 동북4구 도시재생은 상향식 도시정책을 실천하고 공간에 한정된 지역단위 도시재생을 지양하는 진행형 도시재생을 추구한다. 한정된 예산과 인원으로 도시재생을 통해 지역의 모든 문제를 해결할 수 없다. 공간경계를 벗어나 민 · 관 · 학이 함께 지역의 문제점을 발굴하고 각 주체들이 잘 할 수 있는 것을 한다면, 효율성을 담보한 도시재생을 실현할 수 있을 것이다. Cities have the same properties as organisms that grow and decline through relationships with surrounding areas. In other words, problems that occur in the region are not unique to the region, and most often affect the surrounding area. This study analyzed the case of four ‘gu’s in northeastern areas of Seoul where regional problems from the perspective of urban regeneration are solved through cooperation between neighboring local governments. The purpose of this study is to present the direction and strategy of urban regeneration according to changes in internal and external conditions. The results of the analysis suggest, that the limited budget and personnel cannot solve all problems through urban regeneration. If the public, government, and academia work together to find local problems and do what each subject can do well, they will be able to realize urban regeneration with efficiency guaranteed.