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Upwind Navier-Stokes 방정식을 이용한 무딘 물체 주위의 유동장 해석
권창오(C. O. Kwon),김상덕(S. D. Kim),송동주(D. J. Song) 한국전산유체공학회 1996 한국전산유체공학회지 Vol.1 No.1
In this paper the upwind flux difference splitling Navier-Stokes method has been applied to study the perfect gas and the equilibrium chemically reacting hypersonic flow over an axisymmetric sphere-cone(5˚) geometry. The effective gamma(r). enthalpy to internal energy ratio was used to couple chemistry with the fluid mechanics for equilibrium chemically reacting air. The test case condition was at altitude(30Km) and Mach number(15). The equilibrium shock thickness over the blunt body region was much thinner than that of perfect gas shock. The pressure difference between perfect gas and equilibrium gas was about 3-5 percent. The heat transfer coefficient were also calculated. The results were compared with VSL results in order to validate the current numerical analysis. The results from current method were compared well VSL results; however. not well at near nose. The proper boundary condition and grid system Will be studied to improve the solution quality.
PET 용기 제작을 위한 프리폼 사출 성형에 대한 수치적 연구
권창오(Chang-Oh Kwon),김종덕(Jong-Deok Kim),김정순(Jeong-Soon Kim) 한국산업융합학회 2007 한국산업융합학회 논문집 Vol.10 No.4
This study presents the preform injection molding of the injection stretch-blow molding process for PET bottles. The numerical analysis of the injection molding of a preform is considered in this paper using CAE with a view to minimize the warpage. In order to determine the design parameters and processing conditions in injection molding, it is very important to establish the numerical model with physical phenomenon. In this study, a three dimensional model has been introduced for the purpose and flow simulations of filling, post-filling and cooling process are carried out. The simulations resulted in the warpage in good agreement with the measurements. Also, from the result of numerical analysis, we appropriate -ly predicted the warpage, deformation and thickness distribution along the preform wall.
PTMSP/PDMS-PEI 복합막을 이용한 폐수중의 휘발성 유기화합물 제거에 관한 연구
권창오(Kwon, Chang-Oh),백귀찬(Paik, Gwi-Chan),전경수(Chun, Kyung-Soo) 한국산학기술학회 2011 한국산학기술학회논문지 Vol.12 No.8
Poly(1-trimethylsilyl-1-propyne)/poly(dimethylsiloxane)-polyetherimide (PTMSP/PDMS-PEI) 복합막을 상전환법과 dip coating에 의해 제조하여 PTMSP/PDMS 균질 치밀막의 투과유량을 향상시키고자 하였다. 균질 치밀막과 복합막을 이용하여 투과증발법에 의해 수중에 용해된 미량의 perchloroethylene(PCE), trichloroethylene (TCE), chloroform, 1,1,1-trichloroethane 등의 휘발성 유기화합물 제거 실험을 통해 투과증발 특성을 상호 비교하였다. PTMSP/PDMS 균 질 치밀막의 선택도는 216.2에서 2394.4범위의 값을 나타냈으며 투과유량은 244.3g/㎡.h에서 428.2g/㎡.h 사이였으며, PTMSP/PDMS-PEI 복합막의 선택도는 215.5에서 2404.2범위였고 투과유량은 390.4g/㎡.h에서 728.6g/㎡.h 값을 보여 이 복합막의 투과특성을 균질 치밀막과 비교할 때 선택도에는 큰 차이가 없었으나 투과유량은 상당히 증대되었다. PTMSP/PDMS-PEI 복합막은 분리대상 용질 중 PCE의 분리에서 가장 우수한 투과특성을 나타냈으며 균질 치밀막보다 내구성과 기계적강도가 좋아 물속에 용해되어 있는 휘발성 유기화합물을 제거하는데 유용함을 알 수 있었다. In order to improve flux of PTMSP/PDMS dense membrane, PTMSP/PDMS-PEI composite membrane with PEI support was prepared by phase inversion process and dip coating. These membranes were evaluated in terms of the removal of volatile organic compounds such as PCE, TCE, chloroform, 1,1,1-trichloroethane from wastewater by pervaporation. The selectivity and flux of PTMSP/PDMS dense membranes was in the range of 216.2 to 2394.4 and 244.3 to 428.2g/m2h, respectively. And pervaporation property of PTMSP/PDMS-PEI composite membrane was in the range of 215.5 to 2404.2 and 390.4 to 728.6g/m2h, respectively. PTMSP/PDMS-PEI composite membrane has remarkably greater flux than dense membranes with similar selectivity. It was possible for polymeric membranes used in this study to remove PCE selectively which is dissolved small quantity in water among other separable solutes. PTMSP/PDMS-PEI composite membrane showed the best performances among the silicone polymeric membranes, and has better durability and mechanical strength than dense membranes. PTMSP/PDMS-PEI composite membrane should be a useful candidate for the removal of volatile organic compounds dissolved in wastewater.