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용융아연 도금공정에서의 SNOUT 내부 유동장 해석 ( I )
신대식,최제호,이상준,Shin, Dae Sig,Choi, Jayho,Lee, Sang-Joon 대한기계학회 1999 大韓機械學會論文集B Vol.23 No.10
PIV(Particle Image Velocimetry) velocity field measurements inside the snout of a1/10 scale model of the Zn plating process were carried out at the strip speed $V_s=1.5m/s$. Aluminum powder particles ($1{\mu}m$) and atomized olive oil ($3{\mu}m$) were used as seeding particles to simulate the molten Zinc flow and deoxidization gas flow, respectively. A pulsed Nd:Yag laser and a $2K{\times}2K$ high-resolution CCD camera were synchronized for the PIV velocity field measurement. From flow visualization study, it is found that the liquid flow in the Zn pot is dominantly governed by the uprising flow caused by the rotating sink roll, with its effect on the steel strip inside the snout largely diminished by installing of the snout. The deoxidization gas flow in front of the strip inside the snout can be characterized by a large-scale vortex rotating clockwise direction formed by the moving strip. In the rear side of the strip, a counter-clockwise vortex is formed and some of the flow entrained by the moving strip impinges on the free surface of molten zinc. The liquid flow in front of the strip is governed by the flow entering the snout, caused by the spinning sink roll. Just below the free surface a counter-clockwise vortex is formed near the snout wall. The moving strip affects dominantly the flow behind the strip inside the snout, and large amount of the liquid flow follows the moving strip toward the sink roll. The thickness of the flow following the strip is very thin in the front side due to the uprising flow, however thick boundary layer is formed in the rear side of the strip. Its thickness is increased as moving downstream toward the sink roll. Inside the snout, the deoxidization gas flow above the free surface is much faster than the liquid flow in the zinc pot. Due to the larger influx of the flow following the moving strip in the rear side of the strip, higher percentage of imperfection can be anticipated on the rear surface of the strip.
PIV 계측 및 수치해석 기법을 이용한 고효율 냉장고 설계
남영석(Young-Sok Nam),조성호(Sung-Ho Cho),최제호(Jayho Choi),이인섭(In-Seop Lee) 대한기계학회 2002 대한기계학회 춘추학술대회 Vol.2002 No.5
A PIV measurement and numerical analysis of the flow inside the refrigeration compartment was conducted to increase the refrigerator performance. This study was especially focused on temperature uniformity and cooling speed performance. 2D PlY and stereoscopic PlY were used for the experiments on an actual-size operating refrigerator. The flow patterns inside the shelves and door baskets were measured by 2D PIV and the flow-rates at cooling duct outlets were measured by stereoscopic PlY. For numerical analysis, commercial software was used. 320,000 structured grid systems made with body fitted coordinate and the standard k-ε turbulence model were used for numerical analysis. Numerical analysis was used to calculate velocity vectors and temperature distributions inside cooling ducts and the refrigeration compartment as a whole. The new cooling system developed with the results of this analysis, cooled the door baskets effectively and according to chamber tests, temperature uniformity and cooling speed performance were increased 25%, and 11 %, respectively.
임준영(Jun-young Lim),김상영(Sang-young Kim),이요한(Yo-han Lee),최용원(Yong-won Choi),최제호(Jayho Choi) 전력전자학회 2004 전력전자학술대회 논문집 Vol.- No.-
This paper presents Single Phase SRM for the vacuum cleaner. The advantage of SRM is long life time, high suction power.