전조등 교통사고 방지와의 상관관계에 대한 운전자의 의식 조사

승삼선,강화순 三陟大學校 産業科學技術硏究所 2003 産業科學技術硏究論文集 Vol.8 No.2

We have surveyed driver s attitude for correlation between use of head lamps and road accidents prevention. The contents of questionnaire consist of 10 fundamental questions related with drivers' own and 20 questions related with head lamps. The collected data have been analyzed using Excel and the number of questionnaire sheet were 244. With analysis results. we suggest that the agencies concerned. the car makers. and drivers give a damn each other and remedy the state of things for road accidents prevention related in head lamps.

교육용 송풍기의 개량과 그에 따른 특성 연구

승삼선,유신오,노경호 三陟大學校 産業科學技術硏究所 2002 産業科學技術硏究論文集 Vol.7 No.1

In this study, open type wind tunnel has been restructured instead air blower. its designed and fabricated part are diffuser. settling chamber with screen, contraction or nozzle, and test section. Also inverter enable to control variable speeds. And basic experiments have been performed to check the flow characteristics for restructured open type wind tunnel. In these procedures, we have got some conclusion. the control of contraction is valid for X = 0.40 considering Morel's and Fang's suggestion. it is confirmed that the two pressure coefficients for avoiding separation is satisfied with Fang's result. Distribution of uniform velocity in test section are stabilized above 95~99%.

Shock wave propagation in bubbly liquids at small gas volume fractions

승삼선,곽호영 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.3

It is well known that shock wave propagation in liquid media is strongly affected by the presence of gas bubbles that interact with the shock and in turn affect the gas bubbles. An explicit form of a wave equation was obtained from a set of equations for wave propagation in bubbly liquid (Caflisch et al., 1985a) in this study. Shock wave propagation in bubbly mixtures was considered with the solution for the obtained wave equation, of which homogeneous and particular solutions provide the pressure field due to the shock profile and bubble-bubble interaction, respectively. The gas behavior inside a spherical bubble under the shock wave was obtained by a set of homologous solutions for the mass and momentum conservation equations. The energy equation for the gas inside the bubble was solved analytically with help of the homologous solutions. The bubble wall motion in compressible medium was obtained from the Keller-Miksis equation. The heat transfer from/to the bubble was obtained by solving the energy equation for the gas inside the bubble and for the liquid outside the bubble wall. The relaxation oscillations behind the shock front, which were calculated using the Keller-Miksis equation with the solutions of the obtained wave equation, are in close agreement with those obtained in shock tube experiments for a uniform bubbly flow by Kameda et al. (1998). Heat exchange between the gas bubbles and the liquid and the interaction between bubbles were found to be very important factors to affect the relaxation oscillations in the shock front.

홈이 있는 내부 원통에서 홈의 깊이가 Taylor Vortex 형성에 미치는 영향

승삼선,민종식,유신오 三陟大學校 産業科學技術硏究所 2003 産業科學技術硏究論文集 Vol.8 No.2

We have used the technique of visualization to study influences on Taylor vortex flow formation in a fluid contained between concentric cylinders with grooved rotating inner cylinders. Where the grooved rotating inner cylinders mean having the different radius ratio compared with another straight part of inner cylinder. And they have different groove's depth in each grooved inner cylinders. Major parameters in these experiments are radius ratio by the shapes of inner cylinder. and angular velocity of inner rotating cylinder. So we found that results of this experimental study as follows. 1) A radius ratio has an effect on width of bands in rotating inner cylinder. In grooved sections. band width is wider than other straight section of inner cylinder. Especially in case of 1G9 and 1G12, groove's depth is related to unifying one wide band in grooved section. 2) In higher angular velocity. strong source flow occurred toward center of grooved section in case of 1G9 and 1G12. So it is guessed that groove's depth plays a important role in the process to promote turbulent Taylor vortex.

열원이 있는 정육면체 공간내의 공기 및 이산화탄소에 의한 자연대류-복사 열전달 수치해석

승삼선,이창형 三陟大學校 2001 論文集 Vol.34 No.1

In this study, natural convection-radiation heat transfer of air and CO2 gas in cubic enclosure is investigated numerically. The numerical results show that temperature profile is up about 5~15% compared with experimental results. But the trend for temperature profile is similar to experimental results. That means that the natural convection and surface radiation are responsible for the air, while the natural convection and volumetric radiative transfer are important to the heat transfer mechanism for the carbon dioxide.

T.A.B 실시 유무에 따른 대공간의 열환경 특성

승삼선 ( Sam Sun Seung ),이승철 ( Seung Chul Lee ) 대한설비관리학회 2010 대한설비관리학회지 Vol.15 No.2

It is important to evaluate thermal environmental characteristics and the amenities in a large space such as a building with a performance hall. Because there are sometimes occurred inefficient HVAC system operation and excessive energy consumptions. Especially in a thermal environmental view, people feel thermal displeasure because of temperature differences between vertical and horizontal directions. We have performed thermal environmental characteristics analysis for N Korean performance arts center by using CFD techniques. Consequently we confirmed that supply flow balancing after T.A.B decreased thermal stratification locally and increased people`s thermal comfort. So it is necessary to carry out T.A.B for HVAC system in a large space. And it can be used as a fundamental design data for large space design.

홈으로 된 내부형상이 Taylor Vortex 형성에 미치는 영향

유신오,승삼선 三陟大學校 1997 論文集 Vol.30 No.1

We have used the technique of visualization to study influences on Taylor vortex flow formation in a fluid contained between concentric cylinders with grooved shape of inner cylinder. Where the inner cylinder is rotating. So we found that radius ratio and aspect ratio have an effect on flow structures and processes from laminar Taylor vortex to turbulent Taylor vortex. The results of this experimental study are as follows : 1) In laminar Taylor vortex, a radius ratio has an effect on width of cells by rotating inner cylinder with grooved shape. So cell's width of grooved section is wider than its of straight shape. 2) Aspect ratio according to width of groove has an effect on axis of cell to which is leaned over each side of groove. Especially the number of grooves and the ratio of aspect ratio in total straight shape to aspect ratio in grooved shapes play a important role in leanings towards axis of cell in grooved section. 3) In high speed, grooved sections in an inner cylinder play a role in delaying fully developed turbulence except itselves. And it related with radius ratio. 4) In turbulent Taylor vortex, effects of aspect ratio which is effected on axis of cell which is leaned over each side of groove are disappeared. But effects of radius ratio which are caused cell's width of grooved section is wider than straight shape are still appeared.

경사진 내부 원통의 형상비 변화에 따른 Taylor Vortex에 대한 실험적 연구

유신오,승삼선 三陟大學校 1996 論文集 Vol.29 No.1

We have used the technique of visualization to study the formation and extinction of Taylor vortex flow in a fluid contained between concentric cylinders with the ramped rotating inner cylinder. Where the ramped inner cylinder means the different aspect rating. compared with straight inner cylinder. And we focus how the ramped inner cylinder play a role in formation and extinction of Taylor vortex flow. The results of this experimental study are follows 1) In low speed, zigzag type cells form in the sub-critical section during formation of Taylor vortex flow. But the ramped section in an inner cylinder prohibit zigzag type cell from formation in the super-critical staight section. 2) In high speed, ramped section in an inner cylinder play a role in promoting turbulent Taylor vortices. 3) We assume that some bifurcation occurred during process from Taylor vortex flow to fully-developed turbulent flow. 4) In the R=6370, turbulent Taylor vortices exist in a straight inner cylinder. But in a ramped section with inner cylinder, Taylor vortices expire and fully-developed turbulent flow exists.

발열체가 설치된 정육면체 공간내의 공기 및 이산화탄소에 의한 자연대류-복사 열전달 실험 연구

승삼선,이창형,이경영 三陟大學校 2000 論文集 Vol.33 No.1

Heat transfer by radiation is an important phenomena in industrial furnaces, combustors, and other high temperature thermal systems. Development of the numerical modeling schemes for the radiative transfer usually rely on the measured data for a well defined experimental system. It is the purpose of this paper to acquire measured heat transfer data where the effect of the radiative transfer is significant. We considered a closed enclosure filled with the two different gases; air and carbon dioxide. The natural convention an surface radiation are responsible for the heat transfer mechanism for the air, while the natural convention and the volumetric radiative transfer are important to the heat transfer mechanism for the carbon dioxide. The measured temerature distributions show that the carbon dioxide results in the higher temperature distibutions in the cold regions while the air results in the higher temperature distirbutions in the hot regions. The same trend is observed to be amplified as the heater temperature increased.

공기역학적 개념을 고려한 자동차 설계에 대한 고찰

유신오,승삼선 三陟大學校 1996 論文集 Vol.29 No.1

In this review, we have researched vehicle design considering aerodynamic concepts. Especially under high speed conditions, aerodynamic concepts play an important role in vehicle design. And we know that optimization method of each part in producted vehicles introduced by Hucho et al. is very useful. Therefore nowadays we must try to design vehicle styling and optimization method of each part in the futrue cars. Also in today's competitive environment there is a need to create a synergy effect between the EFD(Experimental Fluid Dynamics) and CFD(Computational Fluid Dynamics) process.