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양광혁,박재관,김현준,백송열,박순태,Yang, Kwangheok,Park, Chaegwan,Kim, Hyeonjoon,Baek, Songyoul,Park, Soontae 한국플랜트학회 2016 플랜트 저널 Vol.12 No.3
Wind-induced vibration is a phenomenon that a struture is oscillated due to wind force such as buffeting, vortex shedding wake and etc., which is one of important characteristics to be considered for design in case that stack has significant slenderness ratio or low natural frequency. International design standards of stack define several criteria for evaluating the suitability of stack design, which describe the required design considerations for each range of design parameters and provide the instruction to verify the stack design against wind-induced vibration simply. However, there is a limitation that they cannot provide quantitative information in case code requirement cannot be satisfied due to constraints of plant space or economical design. In order to overcome the limiation of code, integrated numerical analysis of computational fluid dynamics, harmonic analysis and finite element analysis were proposed to investigate wind-induced vibration for multiple stacks in actual plant. Simulated results of mutual wake interference effect between adjacent stacks were evaluated and compared to the criteria in international standards. 풍진동(Wind-induced vibration)은 바람에 의해 구조물에 진동이 발생하는 현상으로써 세장비가 큰 열기기 Stack 설계시 고려해야 할 중요한 사항이다. 따라서, 국제 규격에는 풍진동에 대한 설계 인자와 각 범위에 대해 필요한 고려 사항을 정의하고 있다. 규격에 의한 설계 검증은 몇몇 인자를 이용하여 간단하게 확인이 가능하다는 장점이 있는 반면, 실제 풍진동에 의한 영향을 정량적으로 평가하지 않기 때문에 실제 필요한 것보다 과도한 설계를 요구할 수 있다는 단점이 있다. 또한 여러 제약조건으로 Code 상의 요구조건을 만족하지 못하는 경우 실제 시스템의 거동을 예측할 수 없다는 단점이 있다. 이러한 점을 보완하기 위해 CFD 와 FEM 등의 수치적 해석 방법을 통해 풍진동이 실제 Stack에 미치는 영향을 해석하여 설계 적정성을 검증하여 Code 상의 요구 조건과 비교하였다.
양광혁(Kwangheok Yang),최상민(Sangmin Choi),정진경(JinKyung Jung) 한국연소학회 2006 KOSCOSYMPOSIUM논문집 Vol.- No.-
At the furnace top, the distribution of charging coke and ore is adjusted to control the reducing gas flow distribution in the furnace. It is necessary to predict operation condition of blast furnace according to the burden profile to judge whether charging is properly conducted In this study, We propose the model for predicting while layer structures whithin furnace when top burden profile was given. Layer structure of coke and ore could be predicted by top burden profile and solid velocity. Solid velocity is assumed as potential flow. Potential function distribution and timeline are also calculated using solid velocity field. The Calculation is conducted for different burden profile cases. As the result burden distribution and grid structure, which is deformed to match the layer structure in shaft and deadman profile. Gas flow was calculated using this grid, and calculated results are compared with each other.
양광혁(Kwangheok Yang),양원(Won Yang),최상민(Sangmin Choi) 대한기계학회 2004 대한기계학회 춘추학술대회 Vol.2004 No.11
Coking process is the thermal decomposition of bituminous coal with final temperature of about 900℃ Because coke plays important roles in ironmaking process in a blast furnace it's essential for developing modeling of coke oven. In this study, An unsteady 2-dimesional model is proposed to simulate coking process in a coke oven. In this model, gas and solid phase are assumed homogeneous continnum and solid bed is assumed as porous media . The model contains governing equations for the solid phase and the gas phase. Complicated phenomena such as swelling, softening, resolidification and shrinkage are neglected and mass loss by drying and devolatilization is reflected by generation of internal pores. Drying, devolatilization, heat transfer and generation of internal pores are also reflected in source terms. Calulated results are compared with experimental data
양광혁(Yang Kwangheok),최상민(Choi Sangmin),정진경(Jung Jinkyung) 한국연소학회 2006 KOSCOSYMPOSIUM논문집 Vol.- No.-
Analysis of the internal state of the blast furnace is needed to predict and control the operating condition. Especially, it is important to develop modeling of blast furnace for predicting cohesive zone because shape of cohesive zone influences overall operating condition of blast furnace such as gas flow, chemical reactions and temperature. because many previous blast furnace models assumed cohesive zone to be fixed, they can't evaluate change of cohesive zone shape by operation condition such as PCR, blast condition, and production rate. In this study, an axi-symmetric 2-dimensional steady state model is proposed to simulate blast furnace process. In this model, cohesive zone is changed by solid temperature range, FVM is used for numerical simulation. To find location of cohesive zone whole calculation procedure is iterated Until cohesive zone is converged. Through this approach, shape of cohesive zone, velocity, composition and temperature within the furnace are predicted by model.
Kwangheok Yang(양광혁),Sangmin Choi(최상민),Jinkyung Chung(정진경) 한국연소학회 2008 KOSCOSYMPOSIUM논문집 Vol.- No.-
A blast furnace can be modeled in a similar approach using a counter-current bed reactor. In the present study, an axi-symmetric two-dimensional steady state model is proposed to simulate the blast furnace process. It is assumed that only two phases (solid and gas phases) exist in the furnace. The charging material is treated as porous media constructed by coke and ore layers. The internal gas flow of the furnace is controlled by burden distribution owing to the different permeability of the two layers. For an understanding of the influence of the burden distribution on the operating conditions, the entire layer structure is predicted from the measured top layer structure and the solid flow is assumed according to the potential flow. Using this burden distribution, the flow, energy, and chemical species conservation equations are considered for each phase. In addition, the mass generation/consumption according to the reaction, heat transfer between the gas and the solid phases, and the reaction heat are reflected by source terms in the governing equations. For several Lo/Lc (layer thickness ratio of ore and coke layer) cases, layer structures are constructed and numerical simulations are conducted. The finite volume method was used for the numerical simulations. Through this approach, the flow, composition and temperature within the furnace are predicted by the model.
양원(Won Yang),류창국(Changkook Ryu),양광혁(Kwangheok Yang),최상민(Sangmin Choi) 대한기계학회 2003 대한기계학회 춘추학술대회 Vol.2003 No.11
Thermo-fluid characteristics in coke oven, sintering machine and blast furnace in iron-making facility are key processes related to the quality and productivity of the pig iron. Solid material in the processes usually forms a bed in gas flow. For simulation of the processes by mathematical model, the solid beds are assumed as continuum and reacting solid flow in the gas flow. Governing equations of partial differential equation forms for the solid material can be constructed based on this assumption. Iron ore sintering bed is simulated and limited amount of parametric study have performed. The results have a good agreement with the experimental results or physical phenomena, which shows the validity and applicability of the model.