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손창현(Changhyun Sohn),정문부(Moonbu Jeong),최종하(Jongha Choi) 한국자동차공학회 2004 한국자동차공학회 지부 학술대회 논문집 Vol.- No.-
The present numerical study analyzes the car fuel filler pipe using a three-dimensional steady as well as unsteady VOF (Volume of Fluid) method. The unsteady calculations show that fuel is separated from liquid and gas by gravity. The liquid velocity of pipe depends on the pipe gradient. Air pockets are found at regions with sharp bends in a small radius pipe region. The results of unsteady calculation show that the main reason of bubble generation in a fuel tank may not be due to cavitation or separation in a pipe. To design optimal fuel filler pipes, it is necessary to design pipes with nearly identical gradient as possible and reduce regions of the suddenly decreasing radius.
비압축성과 압축성 유동에 있어서 비점성 유동과 경계층 유동의 결합
손창현(Changhyun Sohn),문수연(Suyeon Moon),이정윤(Jeongyun Lee) 대한기계학회 2003 대한기계학회 춘추학술대회 Vol.2003 No.4
Matching inviscid and boundary layer methods are developed for hypersonic flow with thick<br/> boundray layer. The new equations match all the boundary layer properties with a variation in the<br/> inviscid solution near the edge, except for the normal velocity. Computational comparison are<br/> performed for incompressible and compressible flows over a flat plate. Results from the present<br/> method are compared with Navier-Stokes solutions. The present results are in good agreement with<br/> Navier-Stokes solutions. They show that the new technique can provide improved heating rates and skin<br/> friction predictions for preliminary design of vehicles where shear layers and entropy layer swallowing<br/> are important.
손창현(Changhyun Sohn) 한국자동차공학회 2002 한국자동차공학회 춘 추계 학술대회 논문집 Vol.2002 No.5_3
The vortex tube is a simple energy separation device without moving parts and any chemical reaction. This energy separation phenomenon by vortex tube has attracted interest from various points of view because of simple structures, non-moving parts and no chemical reactions. Additionally, vortex tube can be used a cooling device without any envirorunental problem. Despite of various investigations have performed on the vortex tube, the fundamental mechanism of this phenomenon is still in question. The present study investigated energy separation mechanism and phenomena for the counter-flow type vortex tube by a numerical simulation. Three-dimensional computational study was conducted to obtain more detail flow field of the vortex tube. Calculated total pressure, static pressure and temperature distributions in a vortex tube were compared with other researehers experimental data and gave very good agreements with experimental results. Two pair secondary flow (total 4 secondary flow region) in a vortex tube was found. The flow behavior of a secondary flow in a vortex tube was similar the Rankin cycle process and the energy separation of the vortex tube was mainly caused by secondary flow.
김중희(Joonghui Kim),손창현(Changhyun Sohn) 한국자동차공학회 2012 한국자동차공학회 지부 학술대회 논문집 Vol.2012 No.4
GDI(Gasoline Direct Injection) enables a stratified fuel charge combustion for improved fuel efficiency, and reduced emission levels at low load. Analysis of the heat transfer on a GDI pump is conducted by Fluent. The exterior temperature boundary conditions which changing with time were applied by UDF(User Defined Function). This study simulated the temperature and heat flux of the interior section of GDI pump for with natural convection condition. The calculated temperature at given pressure is use to classify the vapor generation phenomena.
권영두(Youngdoo Kwon),이준혁(Junhyuk Lee),손창현(Changhyun Sohn),최종하(Jongha Choi),임재규(Jaegyoo Lim),이헌우(Hunwoo Lee) 한국자동차공학회 2004 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Link-system is necessary to transfer power and has widely been used in many fields such as an automobile, robot, mechanical engineering. This dissertation indicates that we design double three-bar and double four-bar driver by motor so that they can have each other difference degree. Therefore, we analyze link mechanism to have the same output for each bar coping with the same input for it. Unless it is accomplishes, we will look for the length and position of the link minimizing weight. We used SZGA(Successive zooming genetic algorithm; Computers & Structure, 2003), the technique of optimum design, the optimum value obtained by it is verified by an experiment, fortran link program developed in person and Recurdyn which is 3-D Dynamic Mechanics Analysis package.
튜브형상에 따른 배기가스 재순환 냉각 장치 열전달 성능 평가
최종하(Jongha Choi),슬량(Shi Yang),정문부(Moonbu Jung),손창현(Changhyun Sohn) 한국자동차공학회 2004 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
With the Euro-4 regulation coming into effect from 2005, the domestic car industry is forced to look for newer options to reduce NOX in the exhaust. EGR(Exhaust Gas Recirculation) cooler is an effective method for the reduction of NOX form a diesel engine. High efficiency, low pressure loss and compactness are desirable features of an EGR Cooler. The cooling performance of EGR depends on the shape of tubes and the location of the entrance and exit.<br/> This paper reports the computational work conducted to estimate the performance of EGR cooler with three different cross section tubes and a triangular spiral tube. Three dimensional computation results show that the triangular tube is more effective than circular and rectangular tube. The most effective geometry is a triangular spiral tube with offset inlet and outlet locations.
최종하(Jongha Choi),슬량(Shi Yang),정문부(Moonbu Jung),손창현(Changhyun Sohn) 한국자동차공학회 2004 한국자동차공학회 지부 학술대회 논문집 Vol.- No.-
With the Euro-4 regulation coming into effect from 2005, the domestic car industry is forced to look for newer options to reduce NO_x in the exhaust. EGR (Exhaust Gas Recirculation) cooler is an effective method for the reduction of NO_x form a diesel engine. High efficiency, low pressure loss and compactness are desirable features of an EGR Cooler. The cooling performance of EGR depends on the shape of tubes and the location of the entrance and exit. This paper reports the computational work conducted to estimate the performance of EGR cooler with three different cross section tubes and a triangular spiral tube. Three dimensional computation results show that the triangular tube is more effective than circular and rectangular tube. The most effective geometry is a triangular spiral tube with offset inlet and outlet locations.