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대향류형 보텍스 튜브의 노즐형상 변화에 따른 튜브 내부의 온도분포에 관한 실험적 연구
황승식(Seungsik Hwang) 한국자동차공학회 2002 한국 자동차공학회논문집 Vol.10 No.4
The aim of this study is to provide fundamental informations that make it possible to use a cool stream and a hot stream simultaneously. We changed the pressure of compressed air that flows into a tube, the inner diameter of orifice that a cold stream exits, and the mass flow rate ratio. And in each case, we measured the temperature of a cold stream and a hot stream in each exit of a tube. Also we measured the axial and the radial temperature distribution in internal space of a tube. From the study, following conclusive remarks can be made. First, As the number of nozzles increase, separation point move into the hot exit. Second, When we use guide vane type nozzle, the axial temperature distribution constant over the 0.75 of air mass flow rate ratio. Third, When we use Spiral type nozzle, axial and radial temperature distribution in the inner space is higher than another nozzle. Fourth, Axial and radial temperature distribution in the inner space vortex-tube is determined by separation point. And separation point is moved by changing of air mass flow rate ratio. At last, A heating apparatus is possible for vortex-tube to use.
대향류형 보텍스 튜브에서의 형상 변화에 따른 온도 분리에 관한 실험적 연구(I)
황승식(Seungsik Hwang),전운학(Unhack Chun),김종철(Jongchul Kim),이희상(Heesang Lee) 한국자동차공학회 2001 한국 자동차공학회논문집 Vol.9 No.1
The aim of this study is to provide fundamental informations that make it possible to use a cool stream and a hot stream simultaneously. We changed the pressure of compressed air that flows into a tube, the inner diameter of orifice that a cold stream exits, and the mass flow rate ratio. And in each case, we measured the temperature of a cold stream and a hot stream in each exit of a tube. Also we measured the axial temperature distribution and the radial temperature distribution in internal space of a tube. From the study, following conclusive remarks can be made. Average flow rate that flows into a tube is in proportion to square root of inlet pressure. As inlet pressure increases axial and radial temperature distribution in the inner space of vortex-tube increase. As mass flow rate ratio change, separation point moves.
[기타] 대향류형 보텍스 튜브에서의 입구조건 변화에 따른 온도 분리 효율에 관한 연구
황승식(Seungsik Hwang),선영택(Youngtaek Sun),전운학(Unhack Chun),김종철(Jongchul Kim),이희상(Heesang Lee) 한국자동차공학회 2000 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
The aim of this study is to provide fundamental informations that make it possible to use a cool stream simultaneously. We changed the pressure of compressed air that flows into a tube, the inner diameter of orifice that a cold stream exits, and the mass flow rate ratio. And in each case, we measured the temperature of a cold stream and the efficiency. From the study, following conclusive remarks can be made. As inlet pressure increases temperature distribution to increase. But, efficiency not to change. As a number of nozzle increases efficiency enlarge.
Kim Seungsik,Gu Nami,Moon Jeongin,Kim Keunwook,Hwang Yeongeun,Lee Kyeongjun 한국통계학회 2023 Communications for statistical applications and me Vol.30 No.5
This study aimed to predict the number of meals served in a group cafeteria using machine learning methodology. Features of the menu were created through the Word2Vec methodology and clustering, and a stacking ensemble model was constructed using Random Forest, Gradient Boosting, and CatBoost as sub-models. Re-sults showed that CatBoost had the best performance with the ensemble model showing an 8% improvement in performance. The study also found that the date variable had the greatest influence on the number of diners in a cafeteria, followed by menu characteristics and other variables. The implications of the study include the potential for machine learning methodology to improve predictive performance and reduce food waste, as well as the removal of subjective elements in menu classification. Limitations of the research include limited data cases and a weak model structure when new menus or foreign words are not included in the learning data. Future studies should aim to address these limitations.
황인혁(Inhyuck Hwang),민승식(Seungsik Min),김소연(So Yeon Kim),이용철(Yongchol Lee) 한국해군과학기술학회 2023 Journal of the KNST Vol.6 No.4
In this paper, related case studies and requirements for building a smart classroom were collected and performed relative weight calculations using AHP. In addition, quality function deployment was used to expand requirements into functions and calculate the relative weight for each function. Through this, key functional elements for building a smart classroom were identified and priorities for development were determined.
Ranque-Hilsch tube의 입구 형상 변화에 따른 고온특성에 관한 실험적 연구
전운학,황승식 국민대학교 생산기술연구소 2003 공학기술논문집 Vol.26 No.-
Vortex-tube is a cylindrical device that separates a flow of compressed air into a hot stream and a cold stream. Compressed air flowing tangentially into a tube, it spirals down the tube and produces two flows. Vortex-tube uses nothing but compressed air as a power source. Vortex-tube is being expected as a pro-environment cooling and heating system. The aim of this study is to provide fundamental informations that make it possible to use a cool stream and a hot stream simultaneously and High temperature characteristics especially. To achieve the aim, we changed the inner diameter of orifice that a cold stream exits, the number of nozzles that inject compressed air into a tube, the form of nozzle arrangement and the mass flow rate ratio. And in each case, we measured the temperature of a cold stream and a hot stream in each exit of a tube. Also we measured the axial temperature distribution in surface of a tube. From the study, following conclusive remarks can be made. First, the inner diameter of orifice have an effect on the characteristics of high temperature. Second, when orifice inner diameter is 10mm, range of high temperature is 80% of whole tube surface. Third, when we analyze energy separation effect according to the change of nozzle shape, the high temperature characteristics is affected by the number of nozzles
대항류형 보텍스 튜브의 길이 및 노즐의 위치 변화에 따른 온도 분리 특성에 관한 실험적 연구
전운학,황승식 국민대학교 생산기술연구소 2004 공학기술논문집 Vol.27 No.-
The aim of this study is to provide fundamental informations that make it possible to use a cool stream and a hot stream simultaneously. To achieve the aim, we changed the pressure of compressed air that flows into a tube, the length of tube in a hot stream exits, the position of nozzle that inject compressed air into a tube and the mass flow rate ratio. And in each case, we measured the temperature of a cold stream and a hot stream in each exit of a tube. From the study, following conclusive remarks can be made. Generally as inlet pressure increases, temperature difference between inlet air and outlet air in cold and hot stream increases. When we analyze energy separation effect according to the length change of vortex tube, maximum cold and hot air temperature difference is measured that the ratio of tube length to tube diameter is 35, 20. We find a length of vortex tube that brings effect of the energy seperation better. And as inlet nozzle keep away from the orifice that a cold stream exits by degrees, energy seperation effect is better.
[구조강도부문] 대향류형 보텍스 튜브에서의 에너지 분리에 관한 실험적 연구
전운학(Unhack Chun),황승식(Seungsik Hwang) 한국자동차공학회 2000 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
The aim of this study is to provide fundamental informations that make it possible to use a cool stream and a hot stream simultaneously. We changed the pressure of compressed air that knows into a tube, the inner diameter of orifice that a cold stream exits, and the mass now rate ratio. And in each case, we measured the temperature of a cold stream and a hot stream in each exit of a tube. Also we measured the axial temperature distribution and the radial temperature distribution in internal space of a tube. From the study, following conclusive remarks can be made. Average flow rate that flows into a tube is in proportion to square root of inlet pressure. As inlet pressure increases axial and radial temperature distribution in the inner space of vortex-tube increase. As mass flow rate ratio change, separation point moves.
Ranque-Hilsch tube에서 질량유량비 변화에 따른 고온특성변화에 관한 실험적 연구
선영택(Youngtaek Sun),황승식(Seungsik Hwang),전운학(Unhack Chun) 한국자동차공학회 2001 한국자동차공학회 춘 추계 학술대회 논문집 Vol.2001 No.11_1
The aim of this study is to provide fundamental informations that make it possible to use a hot stream and surface of hot division simultaneously. We fixed the pressure of compressed air that flows into a tube. We changed the inner diameter of orifice that a cold stream exits, and the mass flow rate ratio. And in each case, we measured the temperature of a hot stream and a surface division. From the study, following conclusive remarks can be made. First, when air flow mass ratio is 0.5, hot temperature difference is maximum value. Second, hot stream(50℃) and cold stream( -15℃) can be used by 0.50f air flow mass ratio at the same time. Third, as air flow mass ratio increases, hot temperature point move into the entrance of vortex tube. Fourth, when air flow mass ratio is 0.8. range of hot is 67% of whole tube surface. At last, air flow mass ratio have an effect on the characteristics of hot temperature.