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최성조,윤종규,박병관 대한금속재료학회(대한금속학회) 1986 대한금속·재료학회지 Vol.24 No.4
A mathematical model of a fluid flow in a bottom blown gas-stirred vessel which is widely used in refining process of steel has been developed with the use of Homogeneous Flow Theory corrected by Drift Flux Model. Time-averaged continuity equation, Navier-Stokes equation and K-εturbulence model are applied to the two-dimensional axisymmetric turbulent recirculating flow in a cylindrical vessel and mean velocity distributions, turbulent kinetic energy distributions are computed by Finite Difference Method. The computed results of the velocity distributions are reasonably well agreed with the experimental data of investigators and those of turbulent kinetic energy show semi-quantitative agreements. This numerical experiments show that the fluid flow field in gas-stirred vessel is highly non-uniform and that velocity and turbulent kinetic energy show relatively higher values near free surface and plume zone than the bottom regions of vessel which has very lower values.
최성조,윤종규 대한금속재료학회(대한금속학회) 1986 대한금속·재료학회지 Vol.24 No.4
Through the application of mathematical modelling and water model experiments, a reasonable understanding has been obtained of flow pattern and mixing characteristics in ladle injection metallurgy. It is seen that the flow pattern in gas-stirred cylindrical vessel produces a recirculating vortex located high in the vessel and displaced toward the side wall. Stagnant zone is existing especially at the bottom of the vessel and increased as the H/D ratio is decreased. Mixing time of gas-stirred system is measured by means of a conductivity method. It was found that the time required for the homogenization of the tracer could be readily correlated with the rate of disspiation energy or Froude number. Mixing time also depends on geometry of a vessel. As the H/D ratio of a vessel is decreased, the mixing time is increased. The increase of mixing time in case of low H/D ratio is considered to be the increase of stagnant zone in bottom region.
최성조,강휘진 한국방재안전학회 2022 한국방재안전학회 논문집 Vol.15 No.2
전국 시·도 및 시‧군‧구의 안전 관련 주요통계를 기반으로 사회재난은 지역안전지수 6개 분야( 화재, 범죄, 교통사고, 생활안전, 자살, 감염병)에 대한 전국 지방자치단체의 지역안전지수 등급을 관리하여 개선대책을 수립 시행하고 있으며 자연재난은 자연재해 안전도 진단을 통해 관리체계를 운영하고 있다. 현재 적용하고 있는 자연재해 지역안전도 평가는 읍면동 지역 단위까지 자연재해 지역위험성 평가를 하기에는 내용이 매우 미흡한 실정이며, 지나치게 공학적이고 어렵게 표시되어있어 일반인들이 사용하는데 한계가 있다. 본 연구에서는 외국 선진국에서 주로 사용하는 자연재난과 사회재난이 혼합된 지역위험성평가 모형을 원형으로 하여 우리나라의 자연 재난 지역위험성평가를 읍면동 하위 단위까지 확장된 개선 모형으로 제시하는데 목적이 있다.