밀집형 열교환기의 전열판 배열이 열전달에 미치는 영향

정한식,이광영 慶尙大學校 1995 論文集 Vol.34 No.1

The Effect of heat transfer on the plate arrays in a compact heat exchanger is investigated numerically by using a finite difference method. As Reynolds number increases and the plate length ratio decreases, the optimum spacing of plate arrays become narrow and the total mean Nusselt numbers increase. From these results, the optimum plate spacing and the total mean Musselt number can be expressd by the correlation eqations.

장대형 사각공간에서의 가열원이 난류 자연대류에 미친는 영향

정한식,정효민 慶尙大學校 1998 論文集 Vol.37 No.-

The heat sources effect on turbulent natural convection in large longitudinal rectangular space has been investigated using a finite volume method. The results of the isotherms and velocity vectors have been represented for various heating capacities at the 8 heat sources. At upper position in the space, the temperature and velocity are represented higher value. The mean temperature of the space can be expressed as function with the heating capacity.

사후분해 시체에 대한 법의학적 접근

최영식,이상용,김유훈,조갑래,이봉우,양경무,정낙은,서중석,이한영,이원태,강현욱 大韓法醫學會 2000 대한법의학회지 Vol.24 No.2

Disposal of a homicide victim by dismemberment is rare, but individual cases are on record in most major medicolegal departments. Recognition of postmortem mutilation may be of importance in the interpretation of certain murders committed by sexual perverts and other mentally deranged individuals and sometimes performed for the sole reason of easier disposal of the body. Postmortem dismemberment is usually readily recognizable as such; The edges of the injuries are dry and lack evidence of bleeding. The joints may be disarticulated without fracture, or the use of an axe or saw may be evident from examination of bones. Parallel horizontal or oblique furrows in the bone surface are caused by skipping of the saw prior to establishing depth. Such patterns on the bone may assist in identifying the particular saw involved. So we report 25 dismembered corpses that autopsied in National Institute of Scientific Investigation. This paper can help in attempting to establish not only the first criminal investigation steps but also the medicolegal approach methods in unidentified and dismembered deaths.

종횡비가 사각공간내의 혼합대류 열전달에 미치는 영향

이철재,정한식,김시범,권순석 동아대학교 공과대학 부설 한국자원개발연구소 1995 硏究報告 Vol.19 No.2

The effect of aspect ratio on mixed convection heat transfer in a rectangular enclosure has been studied numerically by the finite difference method. This study has been conducted to evaluate the effects of aspect ratio and position of outlet in the mixed convection for various Reynolds numbers at Pr=0.71 and Gr=10000. Independent of outlet position, as Reynolds number increases, the cell decreases at Re≤100 and then increases at Re〉100 in case R=10., but the cell only increases in case of R+0.5 and R=2.0.

單一핀을 가진 水平管에서 熱傳導率이 自然對流에 미치는 影響

權純錫,鄭漢植 동아대학교 공과대학 부설 한국자원개발연구소 1986 硏究報告 Vol.10 No.1

The effect of conductivity on natural convection from a horizontal heat exchanger tube with a downward projecting fin was studied by analytical method. Local fin Nusselt number is increased gradually at (r-r_(o))≤0.13 and apparently at leading edges of fin. The outer tube temperature for angle represents high as conductivity is low and low as conductivity is high at tube top portion. Excepting top portion, higher conductivity creates higher outer tube temperature. If conductivity is low, the local tube Nusselt number represents high at θ≤60°, low at 60°<θ≤130° and high at θ>130°. Radial velocity reaches maximum value at (r-r_(o))=0.12 and angular velocity reaches maximum value at (r-r_(o))??0.03 for θ=177.5° and also radial velocity reaches maximum value at θ=20° and angular velocity reaches maximum value at θ=175° for (r-r_(o))=0.01. According as conductivity increases, the mean fin Nusselt number and mean total Nusselt number is slightly increased, the mean tube Nusselt number is slightly decreased, and mean outer tube temperature is slightly increased.

두개의 수직평판에서 혼합대류 열전달

김상영,정한식,권순석 東亞大學校 海洋資源硏究所 1992 硏究論文集 Vol.5 No.2

The mixed convection heat transfer from two vertical with in-line, misaligned and parallel arrays is investigated by numertically using the finite differenc emethod and experimentally with Mach-Zehnder interferometer. The dimensionless plate spacing , the dimensionless plte temperature rations, Grashof numbers andReynolds numbers are varied parametically .For misaligned plates and parallel plates, the optimum plate spacings move to the narrow spacing as Reynoldsnumber and ∮??/∮?? increase and can be expressed by the correlation equations at Gr=10?. The optimum plate spacings for parallel pkates sharply move to the narrow spacing comparing with misaligned plates. teh mean and maximum mean Nusselt numbers obtain higher value by ordering parallel, misaligned, and in-line arrays and can be expressed by the correlation equations at Gr=10?,∮??/∮??=1.0.Comparisons between teh exoerimental and numerical result show good qualitative agreements.

水平環狀空間의 熱傳達에서 隔板의 影響

權純錫,李範澈,鄭漢植 東亞大學校 大學院 1988 大學院論文集 Vol.13 No.-

A numerical study have been performed onthe effects of spacers on the heat transfer across a horizontal annulus under basic conditions; Ra=10⁴,Pr=0.7 D??/D??=2.6, K??K=48, ??/D??=0.06 and Nu??=122.5. The mode of heat transfer in the annulus is changed from conduction to convection at Ra??10³. The maximum dimensionless temperature districution along (r-r??)/L at Θ=50?? are founded for vertical spacers but at Θ=120??, for horizontal spacers, and the minimum dimensionless temperature distribution along (r-r??)/L at Θ=50?? are founded for horizontal spacers but Θ=120??, for no spacers. The maximum dimensionless angular velocity at Θ=50??, at (r-r??)/L??0.2 near the inner tube and at(r-r??)/L??0.8 near the outer cylinder but at Θ=120??, it shows at (r-r??)L??0.15 near the inner tube and at (r-r??)L??0.7 for no spacers and vertical spacers and at (r-r??)/L??0.8 for horizontal spacers near the outer cylinder. Finally, the heat transfer by natural convection in the plain annulus is maximum but in the annulus with horizontal spacers in munimum.

電氣工學敎育의 發展方向에 關한 硏究

李鎭局,徐相壽,朴魯峰,李忠鎬,劉鍾哲,金洪奎,趙武濟,韓運東,池平植 충주대 2003 産業科學論文集 Vol.11 No.-

In this paper, we discuss actual conditions for running school of electrical and electronic engineering in domestic universities. Also, we catch hold of industrial circles's demands in electrical engineering education and analyze questionary results according to goes into effect school of electrical and electronic & information engineering in major of electrical and electronec engineering's students. Conclusively, we present suitable model in electrical engineering by correction of problems.

증발 표면적 증대를 위한 수적 분리기 특성에 관한 연구

모종근,공태우,이광영,정효민,정한식,서정세 경상대학교 해양산업연구소 2002 해양산업연구소보 Vol.15 No.-

The purpose of this research is to obtain the characteristics of water-vapor separator for improving the evaporative surface. The experimental system is constituted with water vapor generator, vapor storage tank, laser source for visualization and camera for photography. The efficiency of water-vapor separator can be varied by the kinds of the inside materials. Thus, in this report, we introduced the three kinds of materials with wire scrap, wire brush and sponge. As the experimental results, the wire brush was showed the best efficiency with 185 g/hr.

냉각탑용 수분배기의 특성에 관한 연구

전유신,최석천,이용훈,김세현,정효민,정한식 경상대학교 해양산업연구소 2002 해양산업연구소보 Vol.15 No.-

The main purpose of this research is the investigation of water distributer. The water distributer of this research is installed in evaporative cooling tower system. The performance of this cooling tower system depend on the evaporative surface, and there are many kinds of methods for increasing the evaporative surface. In this research, we introduced the two kinds of spraying system, one is the hole type with hole diameter 1, 2 and 3mm, and the other is the spray nozzle types with nozzle tip diameter of 1 and 2mm. As the experimental results, the case of diameter 2mm showed the best performance.