http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
김재관(J. G. Kim),이준우(J. W. Lee),김규홍(K. H. Kim) 한국전산유체공학회 2010 한국전산유체공학회 학술대회논문집 Vol.2010 No.5
Numerical investigation was conducted to study the effects of after-body configurations and nozzle lip on the PIFS(Plume Induced Flow Separation) and heat flux to the base face. Two dimensional and axi-symmetric non-equilibrium Navier-Stokes solver with k-ω SST turbulence model was used to solve the launching vehicle type configuration with propulsive jet. The experimental result of Robert J. McGhee was compared with our computational results for code validation. Three types of the after-body configurations (Straight, Boat-tail, Flare type) were simulated for this study. And the nozzle lip effect was studies using the three types of base configurations with same simulation conditions. As a result of numerical investigations, higher pressure ratio condition and boat-tail after-body configuration caused severe PIFS phenomenon but the flare type after-body configuration and low pressure ratio suppressed PIFS. Flare type after-body configuration and low pressure ratio case reduced heat flux to base face. The nozzle lip dispersed the heat flux widely along the base face and the nozzle lip.
김재관(J.G. Kim),이준우(J.W. Lee),김규홍(K.H. Kim) 한국전산유체공학회 2011 한국전산유체공학회 학술대회논문집 Vol.2011 No.11
Numerical investigation was conducted to study the effects of after-body configurations and altitude conditions on the PIFS (Plume Induced Flow Separation) and heat flux to the base face. Two dimensional and axi-symmetric Navier-Stokes solver with k-w SST turbulence model was used to solve the various configuration with propulsive jet. The cylinder, boat-tail and flare after-body configurations and six different altitude conditions (5, 10, 20, 30, 40, 50Km) are used in this study. As a result of numerical investigations, higher pressure ratio condition and boat-tail after-body configuration caused severe PIFS phenomenon but the flare type after-body configuration suppressed PIFS. Flare type after-body configuration reduced heat flux to base face.
압력 조건과 기저 온도 조건에 따른 기저 열전달률 계산
김재관(J.G. Kim),이준우(J.W. Lee),최중근(J.K. Choi),김규홍(K.H. Kim) 한국전산유체공학회 2011 한국전산유체공학회 학술대회논문집 Vol.2011 No.5
Numerical study was conducted to simulate the heat transfer on the real launch vehicle base. Three different base temperatures were chosen, to simulate the heat accumulation on the base. Moreover, six different pressure ratio conditions were used to express the different air conditions. As a result, the table that can used to estimate the base heat flux along the base temperature and pressure condition was made.
이준우(J.W. Lee),박태선(T.S. Park) 한국전산유체공학회 2013 한국전산유체공학회 학술대회논문집 Vol.2013 No.5
Three-dimensional turbulent flows of a distribution manifold are studied by turbulence models. It is difficult to introduce real manifolds of various systems. So, to investigate the geometrical effects, a simplified manifold is adopted. The exit configuration depending on the departure angle has advantages to the outflow uniformity. Also the decreased exit area in the streamwise direction improves the uniformity of exit flow. However, for the uniform effusion, the change of exit port by departure angle is more effective them the change of exit area.
스틸코드 연선 시 주요공정에 따른 교정효과의 실험적 관찰
배기현(G. H. Bae),이종섭(J. S. Lee),허훈(H. Huh),이준우(J. W. Lee),이병호(B. H. Lee) 한국소성가공학회 2009 한국소성가공학회 학술대회 논문집 Vol.2009 No.5
This paper deals with the experimental investigation of the steel cord straightening during the stranding process. The over-twisting and roller straightening process are essential to improve the product quality during the stranding process. To investigate the effectiveness of two processes, four experimental cases are constructed according to the use of an over-twister and two roller straighteners. Three assessment items, such as the residual torsion, the arc-height and the preforming ratio, are measured in each experimental case for the quantitative evaluation of a steel cord. The steel cord shape is also measured to investigate the variation of the straightness efficiently after passing through each process. Finally, the effectiveness of the over-twisting and the roller straightening process is explained based on the experimental results.
배기현(G. H. Bae),이종섭(J. S. Lee),허훈(H. Huh),이준우(J. W. Lee),이병호(B. H. Lee) 한국소성가공학회 2009 한국소성가공학회 학술대회 논문집 Vol.2009 No.10
This paper deals with an evaluation of the product quality according to intermesh of the roller straightening process of a steel cord. To perform the experiments, a single-layered steel cord with three sires is selected as a target. Intermeshes at inlet and outlet of the roller straightening device are selected as a respective design parameter. According to two intermeshes of roller straightening device, a design table is generated and experiments were performed. Three assessment items of the product quality, such as the residual torsion, the arc-height and the pre-forming ratio, are measured in each experimental case for the quantitative evaluation of a steel cord. Based on the measured data, the sensitivity of two intermeshes was analyzed and the prediction equation for the product quality of a steel cord was also constructed from the regression analysis.