• 대한설비공학회지:설비저널
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• 제39권12호
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• pp.30-35
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• 2010

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2001년도 춘계학술발표회요약집
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• pp.198-198
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• 2001

• Journal of Advanced Marine Engineering and Technology
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• 제24권2호
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• pp.31-37
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• 2000

This study investigated heat transfer characteristics of refrigeration system using new type aluminium heat transfer tube for evaporator of refrigeration and air-conditioning comparing with bare tube. From the result of heat transfer experiment form one phase flow using cooled and hot water, about 20% heat transfer performance is superior in case of same quantity of flow and about 4% heat transfer performance if superior in case of same velocity comparing with bare tube. Casing of two phase flow, heat transfer performance of new type aluminum heat transfer tube shows about 50% superior heat transfer performance comparing with bare tube in the same evaporating pressure when using heat transfer tube as evaporator and shows about 47% increase when expressing performance coefficient as the rate of refrigerating capacity and compressing work. However, it can be known that pressure drop in the heat transfer tube is taken higher value of about 18% in case of new type aluminum heat transfer tube. From the above result, new type aluminum heat transfer tube is excellent comparing with bare heat transfer tube using the existing heat exchanger for refrigerator.

• 대한기계학회논문집
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• 제19권9호
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• pp.2365-2372
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• 1995

The objective of this study is to get the basic data for the development of fluidized bed combustor. For this purpose, various rake angles(.theta.=20.deg., 25.deg., 30.deg., 35.deg.) of finned tubes and a smooth tube were installed horizontally in the fluidized bed combustor of 410*250mm. The effect of fluidized bed temperature, superficial velocity in bed, size of bed materials, rake angle of finned tubes on the heat transfer coefficient was experimentally investigated. The following results were obtained. (1) Under the fluidized bed temperature(750.deg. C-900.deg. C), and the gas velocity in bed(1.1-2.8m/sec), The highest heat transfer coefficient was measured with the rake angle of finned tubes was .theta.=25.deg. and .theta.=35.deg. for the average fluidized material particle size of 1.22mm and 1.54mm, respectively. Generally, the heat transfer coefficient of finned tubes is 1.4 to 2.4 times larger than that of smooth tubes. (2) The size of bed materials influences the rake angle of finned tubes which can have the highest heat transfer coefficient. As the temperature in bed gets higher, the effect of the rake angle of finned tubes on the heat transfer coefficient becomes greater.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2005년도 창립60주년 기념 추계 학술대회
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• pp.113.2-113.2
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• 2005

• 태양에너지
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• 제19권2호
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• pp.45-56
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• 1999

The performance of vertical and horizontal tubes with extended surface of rectangular and triangular cross section was investigated theoretically for boiling heat transfer. A simple method for numerical program assuming one-dimensional heat flow was used to predict the performance of these extended surface tubes. The object of this study was to predict the effects of the height, thickness, numbers and, clearance of the extended surface on boiling heat transfer. The results showed that extended surfaces are quite effective as compared to plane surfaces especially near the bum-out point and to promote heat flux in boiling heat transfer.

• 한국안전학회지
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• 제15권3호
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• pp.57-65
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• 2000

The stress corrosion crack growth is simulated assuming a small axial surface crack inside a S/G tube. Internal pressure and residual stresses are considered as applied forces. Stress intensity factors along crack front, variation of crack shape and crack growth rate are obtained and discussed. It is noted that the aspect ratio of the crack is not depend on the initial crack shape but depend on the residual stress distribution.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2011년도 춘계학술논문요약집
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• pp.191-192
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• 2011

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1996년도 춘계학술발표회논문집(3)
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• pp.117-122
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• 1996

본 연구에서는 2개사에서 제조된 합금 600 및 합금 690 이음매 없는 관과 진공 유도 용해로 제조한 합금 690 판재에 대하여 부시 환경의 변화에 따른 특성 평가를 행하였다. 부식 평가는 양극 분극 시험을 통하여 행하였으며 부식 환경은 NaCl, HCl, NaOH(＋$Na_2$SO$_4$) 용액 및 Cu$^{＋}$/Cl$^{－}$ SO$_4$$^{2－}$ 용액이었다. 합금 600 및 합금 690의 양극 분극 저항성을 부식 환경에 따라 평가한 결과, 부식 용액의 종류에 따라 서로 다른 분극 거동을 보이고 있으며, 합금 690의 저항성이 합금 600의 저항성보다 우수하게 나타났다. 또한 가성 용액 중에 $Na_2$SO$_4$를 첨가할 경우 부식 속도를 가속화시키고 있다. 한편 Mo이 첨가되지 않은 합금 690M0의 경우는 Cl$^{－}$ SO$_4$$^{2－}$ 비가 증가할수록 공식 저항성이 급격히 감소하고 있으나, Mo이 첨가된 합금 690M2의 경우는 시험한 전체 비율에서 이온의 영향을 받지 않는 것으로 나타나고 있어 합금 690의 공식 저항성에 Mo이 매우 좋은 효과를 보이고 있음을 알 수 있다.

• 대한기계학회논문집B
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• 제20권9호
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• pp.2916-2923
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• 1996

A numerical analysis of the moving bed heat exchanger of solid particles inside the vertical pipe was performed using finite difference method. Also, the theoretical solutions were obtained for comparison when the wall heat flux or the wall temperature was assumed constant. The comparison showed that their results agreed well each other. The moving bed heat exchanger was classified as countercurrent-flow, parallel-flow, and cross-flow types according to the gas flow direction. For each type, the thermal efficiency of heat exchanger was calculated as a function of non-dimensional parameters such as the characteristic length of heat exchanger, Biot number and the ratio of thermal capacities of gas and solid particles.