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2극 50㎐ 대용량 공기 냉각 동기 발전기 설계 적용 기술
이완주(Wan-Joo Lee),임철(Chul Im),김충목(Choong-Mok Kim),황계하(Kye-Ha Hwang),서명덕(Myong-Duk Seo),이성한(Sung-Han Lee) 대한전기학회 2010 대한전기학회 학술대회 논문집 Vol.2010 No.7
수소 및 수냉각 대형 발전기의 설계, 제작 경험을 통해 보유한 설계 기술을 바탕으로 120㎿ 및 150㎿ 공기냉각 발전기 2개 모델을 개발 완료하였다. 모델 개발 과정에서 고정자, 회전자 등 주요 구성품에 대한 신뢰성 및 건전성을 확보하기 위하여 다양한 엔지니어링 및 해석을 수행하였다.
Wedge 형상을 가지는 덕트의 입구유동 조건변화에 따른 열전달 특성에 대한 연구
유원경(Won Kyung Yoo),양장식(Jang Sik Yang),손창민(Chang Min Son),이성한(Sung Han Lee),안대현(Ahn Dai Hyun),황계하(Kye Ha Hwang),김성하(Sung Ha Kim) 대한기계학회 2014 대한기계학회 춘추학술대회 Vol.2014 No.11
This paper studies the effect of inlet cross flow on the heat transfer in narrow radial ducts with the aspect ratio of 12. Total three geometries, one smooth, two wedged ducts, are modeled for analytical studies. Reynolds number is varied in the range from 13100 to 21000. Ratio of the mass flow rate of main flow and cross flow is maintained to 0.5. Heat transfer characteristics of cross flow are compared to those of no cross flow. Normal-inflow (without cross flow) case results show that area-averaged Nu number of smooth duct is highest. Nu number of Wedge 1 duct is 5% lower than smooth duct and Wedge 2 duct is 21% lower than smooth duct. Cross flow case result also show that area-averaged Nu number of smooth duct is highest. Nu number of Wedge 1 duct is 2% lower than smooth duct and Wedge 2 duct is 18% lower than smooth duct. Cross flow case of smooth duct Nu number is decreased 11% than normal inflow case result, Wedge 1 duct is decreased 8% and Wedge 2 duct is decreased 7%.
반경방향으로 분리된 덕트에서 입구유동 조건변화에 따른 열전달 특성 연구
전신영(Shin Young Jeon),손창민(Chang Min Son),양장식(Jang Sik Yang),이성한(Sung Han Lee),안대현(Dai Hyun Ahn),황계하(Kye Ha Hwang),김성하(Sung ha Kim) 대한기계학회 2014 대한기계학회 춘추학술대회 Vol.2014 No.11
Heat transfer and pressure drop inside radially splitted duct is important factor which to decide the efficiency of machine. Promoting heat transfer in radial direction requires a design approach to distribute cooling or heating flow from a source evenly with minimum pressure loss. If the difference between inner and outer diameter of radial system is larger, the whole radial passage should be splitted into several smaller ducts for controlling flow distribution and velocity. In the present study, a radial cooling ducts are modeled at its real scale to investigate flow and heat transfer characteristics experimentally and analytically. The cooling duct system has total twelve radial ducts with mixture of straight and splitted ducts. For the investigation, cooling flow direction varied from radially inward and outward, and it operates in the ranges of Re=14000~28000. Also, to investigate influence of cross flow, inward flow with cross flow was researched. The experiments employs transient heat transfer tests using two narrow band thermochromic liquid crystals. Heat transfer and flow distribution are calculated numerically using finite volume method based on same condition to validate modeling approach against measured data. The results shows good agreements between the tests and prediction. The detailed observation of flow characteristics provides design guides for such a radial cooling duct system.