선상가열시 이동열원 조건에 따른 가열 판재의 온도분포에 관한 연구

최윤환,이연원,최광,Choi, Yoon-Hwan,Lee, Yeon-Won,Choi, Kwang 한국마린엔지니어링학회 2010 한국마린엔지니어링학회지 Vol.34 No.5

Line heating is a manufacture method, which was widely used to machining a curved surface in the ship construction. The qualities using by line heating are very difference compare to the proficiency level of the engineer. So it's mainly depend on the automation equipment instead of the proficiency level engineer. In this study, it would be investigate the temperature distribution of the heating plate, which was used by the automation equipment according to line heating. The main factors are the moving velocity of the heating source, strength and the heating method separately, in temperature distribution while line heating. In this paper, it was investigated the temperature change with the vary of each three variables. The numerical result showed that peak temperature decrease if the moving velocity of the heating source increased. It can also calculate the change quantitatively that the peak temperature and temperature distribution changed linearly with the vary of the heating source. 선박 건조공정에서 외피의 곡면 가공에 많이 사용하는 가공법을 선상가열법이라고 한다. 선상가열법은 엔지니어의 숙련도에 따라 품질의 차이가 커지기 때문에 현재에는 엔지니어의 숙련도에 의존하지 않는 자동화기기를 사용하여 선상가열을 수행하는 경우가 많다. 본 연구에서는 자동화기기를 사용한 선상가열에 의한 가열판재의 온도분포를 조사하고자 한다. 선상가열시 적용되는 주요한 변수는 가열원의 이동속도, 강도 및 가열 방식 등이 있으며, 본 연구에서는 세 가지 변수를 중심으로 가열판재의 표면 및 내부온도가 어떻게 변화하는지를 조사하였다. 해석결과 가열원의 이동속도가 빨라질수록 판재의 피크온도는 낮게 형성되는 것을 확인하였고, 또한 열원의 크기에 따른 피크온도 및 온도분포가 선형적으로 변화하는 것을 정량적으로 계산할 수 있었다.

다상유동을 적용한 섬프장 주위 보텍스 거동에 대한 연구

최윤환(Yoon Hwan Choi),박영규(Young Kyu Park),이규명(Kui Ming Li),이연원(Yeon Won Lee) 대한기계학회 2011 대한기계학회 춘추학술대회 Vol.2011 No.5

There have been many studies on sump models but existing studies of pump sump models mainly validate fluid flow and vortex around a pump intake using a single-phase method. In this study, multi-phase method is used for observation of free surface vortex and cavitations occurring by air inhalation and water pressure drop. The purpose of this study is to compare the multi- phase model and the single-phase model to evaluate the difference between them. Also steady and unsteady simulations are conducted to verify the differences in results according to the analysis conditions. A pump sump test model is calculated using CFD and the following points are observed. 1)The location and the behavior of the free-surface and submerged vortex 2)The Velocity distribution at the pump intake and 3)The free-surface vortex in the multi- phase and single-phase method. TSJ Standard S002:2005 is used for numerical computation for the model of this study. Numerical results show that the unsteady multiphase model is the best condition to implement the creation and dissipation of the vortex along time.

3단 회전식 건조성형장치 설계 프로그램 개발

최윤환(Y. H. Choi),김태식(T. S. Kim),최광(K. Choi),이종훈(Y. W. Lee),이연원 한국동력기계공학회 2005 한국동력기계공학회 학술대회 논문집 Vol.- No.-

In order to prevent the environmental pollution, the dryers are commonly used to treat sludge that one of sewages is polluting the quality of water. Generally, the drying method is various as to the property of material and use. Rotary dryer is a good apparatus to treat them. The rotary dryer is the way that is to make substance transmission and heat using hot air between sludge particle and heated gas. In this paper, we developed a 3-pass rotary dryer for various conditions. The working conditions of dryer are a raw sludge feed rate, input & output water content and operation time etc..

스마트 배수 펌프의 성능향상에 관한 연구

최윤환(Yoon Hwan Choi),이영대(Young Dae Lee),이연원(Yeon Won Lee) 한국유체기계학회 2015 유체기계 연구개발 발표회 논문집 Vol.2015 No.12

수렵인의 자연환경태도와 수렵참여 동기

최윤환(Yun Hwan Choi),김성일(Seong Il Kim) 한국산림과학회 1995 한국산림과학회지 Vol.84 No.1

This study investigates the collective aspects of hunting motivation and hunters` attitude toward natural environment. Data were collected from three different types of respondents : 148 hunters who purchased hunting license between November 1992 and March 1993 in Cholla Province. 120 university students and 260 Suwon residents. The 26 items out of 90 items were selected to develop an attitude scale toward natural environment. Results of ANOVA revealed that there were significant differences among five groups(hunters, urban residents and students from 3 major fields) in terms of their attitude values. Hunters` attitude value toward natural environment was the highest among five different types of respondents. Two major motives for hunting participation are `exercise` and `like out-of-doors`. Factor analysis presents eight motivational dimensions underlying hunter`s involvement in the activities: 1)stewardship, 2)social contact, 3) show-off, 4) sportsmanship, 5) like to kill, 6) recreation/relax, 7) economic gain, and 8) being alone. The correlation between the motivational factor of `economic gain` and the attitudinal item of `relationship between man and nature` was negative(r=-0.28). There is a positive correlation(r=0.24) between the motivation of `being alone` and the attitude of `needs for natural environment`. These relationships indicate that individual`s attitude value decreases when one perceives nature as economic goods, while it increases when one visits nature to relieve stress and to develop self-esteem.

수평력을 받는 Plastic type PCV 밸브 내부 유동 가시화

최윤환(Yoon Hwan Choi),이연원(Yeon Won Lee) 한국가시화정보학회 2012 한국가시화정보학회지 Vol.10 No.1

PCV(Positive Crankcase Ventilation) system is designed to remove blowby gas. In this system, a PCV valve is attached in a manifold suction tube to control the flow rate of blowby gas which generates various operating conditions of an automotive engine. As this valve plays a crucial role, the demand in its design is high owing to the small size and high velocity. For this reason, a numerical investigation was carried out to understand both the spool dynamic motion and internal fluid flow characteristics. As a result, the spool dynamic characteristics(i.e. displacement, velocity, acting force), increase in direct proportion to the magnitude of the pressure difference and indicate periodic oscillating motions. Moreover, the velocity at the orifice region decreases according to the increase in differential pressure due to energy loss caused by the sudden decrease of flow area at the orifice region and the increase of flow volume in front of the spool head. Finally, the mass flow rate at the outlet decreases with the increase of spool displacement.

이동열원의 조건 변화가 선상가열에 미치는 영향에 관한 연구

최윤환(Yoon Hwan Choi),이연원(Yeon Won Lee),최광(Kwang Choi) 한국마린엔지니어링학회 2010 한국마린엔지니어링학회 학술대회 논문집 Vol.2010 No.4

Line heating is a manufacture method, which was widely used to machining a curved surface in the ship construction. The qualities using by line heating are very difference compare to the proficiency level of the engineer. So it's mainly depend on the automation equipment instead of the proficiency level engineer. In this study, it would be investigate the temperature distribution of the heating plate, which was used by the automation equipment according to line heating. The main factors are the moving velocity of the heating source, strength and the heating method separately, in temperature distribution while line heating. In this paper, it was investigated the temperature change with the vary of each three variables. The numerical result showed that peak temperature decrease if the moving velocity of the heating source increased. It can also calculate the change quantitatively that the peak temperature and temperature distribution changed linearly with the vary of the heating source. following instructions give you basic guidelines for preparing camera-ready papers for the Journal of the KOSME. We recommend you to use the HWP word processor.

Venturi-type 실드가스 노즐의 형상 변경에 따른 용접부 주위의 유동해석

최윤환(Yoon Hwan Choi),이연원(Yeon Won Lee),정호윤(Ho Yun Jung),서지석(Ji Seok Seo),조상명(Sang Myung Cho) 한국마린엔지니어링학회 2010 한국마린엔지니어링학회 학술대회 논문집 Vol.2010 No.10

The purpose of this study is to find out the effect of the shield gas distribution on the melting efficiency and penetration shape in TIG welding using the results of the experiment and numerical simulation. A diffusion angle of the shield gas nozzle was changed 5, 10 and 15 degree. Also a convergence diameter of the shield gas nozzle was changed 6, 7 and 8㎜. And 100% Ar gas were used as shield gas in this study. When the shield gas regions become large with decrease of the diffusion angle of the shield gas nozzle. The region of the shield gas is enlarged with increase of the convergent diameters. However, the forces given by the shield gas becomes weak.

선상가열시 이동열원 조건에 따른 가열 판재의 온도분포에 관한 연구

최윤환(Yoon-Hwan Choi),이연원(Yeon-Won Lee),최광(Kwang Choi) 한국마린엔지니어링학회 2010 한국마린엔지니어링학회지 Vol.34 No.4

선박 건조공정에서 외피의 곡면 가공에 많이 사용하는 가공법을 선상가열법이라고 한다. 선상가 열법은 엔지니어의 숙련도에 따라 품질의 차이가 커지기 때문에 현재에는 엔지니어의 숙련도에 의존하지 않는 자동화기기를 사용하여 선상가열을 수행하는 경우가 많다. 본 연구에서는 자동화기기를 사용한 선상가열에 의한 가열판재의 온도분포를 조사하고자 한다. 선상가열시 적용되는 주요한 변수는 가열원의 이동속도, 강도 및 가열 방식 등이 있으며, 본 연구에서는 세 가지 변수를 중심으로 가열판재의 표면 및 내부온도가 어떻게 변화하는지를 조사하였다. 해석결과 가열원의 이동속도가 빨라질수록 판재의 피크온도는 낮게 형성되는 것을 확인하였고, 또한 열원의 크기에 따른 피크온도 및 온도분포가 선형적으로 변화하는 것을 정량적으로 계산할 수 있었다. Line heating is a manufacture method, which was widely used to machining a curved surface in the ship construction. The qualities using by line heating are very difference compare to the proficiency level of the engineer. So it's mainly depend on the automation equipment instead of the proficiency level engineer. In this study, it would be investigate the temperature distribution of the heating plate, which was used by the automation equipment according to line heating. The main factors are the moving velocity of the heating source, strength and the heating method separately, in temperature distribution while line heating. In this paper, it was investigated the temperature change with the vary of each three variables. The numerical result showed that peak temperature decrease if the moving velocity of the heating source increased. It can also calculate the change quantitatively that the peak temperature and temperature distribution changed linearly with the vary of the heating source.

원전 배관 내부유체의 자성 이물질 제거에 관한 연구

최윤환(Yoon-Hwan Choi),김오근(Oh-Kuen Kim),서용권(Yong-Kweon Suh) 한국유체기계학회 2002 유체기계 연구개발 발표회 논문집 Vol.- No.-

This work focuses on eliminating tiny particles from the coolant in a nuclear pipe line by using a permanent magnet on the exterior surface of the pipe. This method have some merits compared with the currently applied methods and is expected to be applied to most of the pipe lines in the nuclear plant. For instance in this method, a ring is attached to the exterior surface of the pipe, so that it does not affect the inflows directly. Further, the cost needed in the initial build-up of the facility is low.