• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.298-301
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• 2001

This paper describes development of electric are furnace model for harmonic analysis, which is based on field data. The proposed model is used to analyze harmonics in actual power system, and the results illustrate the model's capabilities.

• 한국연소학회:학술대회논문집
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• 2006.10a
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• pp.145-150
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• 2006

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.

• 한국전산유체공학회:학술대회논문집
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• 1999.05a
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• pp.199-204
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• 1999

Three dimensional numerical analysis for the turbulent reactive flow and radiative heat transfer in the walking beam type of a reheat furnace in POSCO has been carried out by the industrial code FLUENT. Computations an based on the conservation equations of mass, momentum, energy and species with the $k-{\varepsilon}$ turbulence model and mixture fraction/PDF(Probability Density Function) approach for the combustion rate. Radiative heat transfer is computed by the discrete ordinates radiation model in combination with the weighted-sum-of-gray-gas model for the absorption coefficient of gas medium. The predicted temperture distribution in the reheat furnace and energy flow fractions are in reasonable agreement with the measurement data.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.5
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• pp.87-93
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• 2013

Recently, the amount of the mineral admixture including fly ash and ground granulated blast-furnace slag was increased for the purpose of $CO_2$ gas emission reduction in the concrete industry. However, in the case of korea, estimation model of strength development in concrete structural design code was prescribed a constant value according to cement type and curing method about the portland cement. therefore, the properties of strength development according to time of concrete using fly ash and ground granulated blast-furnace slag does not reflected estimation model of strength development. Accordingly, this paper was evaluated strength according to time on the concrete strength range using fly ash and ground granulated blast-furnace Slag and the strength development constant ${\beta}_{sc}$ of concrete according to the kind of the mineral admixture and mixing ratio was proposed.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.04a
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• pp.156-157
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• 2022

The purpose of this study is to propose a 40MPa mortar mixed design model that applies the neural network theory to minimize wasted effort in trial and error. A mixed design model was applied to each of the 60 data using fly ash, blast furnace slag fine powder and thickened rice husk powder. And in the neural network model, the optimized connection weight was obtained by repeatedly applying it to the MATLAB. The completed mixed design model was demonstrated by analyzing and comparing the predicted values of the mixed design model with those measured in the actual compressive strength test. As a result of the mixed design verification experiment, the error rates of the double mixed non-cement mortar using blast furnace slag fine powder and rice husk powder at a height of 40MPa were 3.24% and 3.4%. Mixed with fly ash and rice husk powder had an error rate of 3.94% and 5.8%. The error rate of the triple mixed non-cement mortar of the rice husk powder, fly ash, and blast furnace slag fine powder was 2.5% and 5.1%.

• 한국연소학회:학술대회논문집
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• 2006.10a
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• pp.160-167
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• 2006

In this project, we studied more accurate and reliable sensing method for oxygen in reheating furnace, made the empirical model for NOx concentration based on oxygen and evaluate the stability of the Tuneable Diode Laser (Absorption) Spectroscopy(TDL(A)S). The tested oxygen monitoring system is installed at work-field reheating furnace on hot roll at POSCO and compared with the Zr sensor system which shows too sensitive because it measures oxygen concentration on a spot unlike TDLS sensor which is successfully applied at 13m-width reheating furnace to measures the line average along the Optical Path Line(OPL).

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.11a
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• pp.107-108
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• 2012

The study on the strength prediction using Maturity is mainly focused on, but the study on the concrete mixing blast furnace slag powder is insufficient. The purpose of this study is to investigate the relationships between compressive strength and equivalent age by Maturity function and is to compare and examine the strength prediction of concrete mixing Blast Furnace Slag Power using ACI and Logistic Curve prediction equation. So it is intended that fundamental data are presented for quality management and process management of concrete mixing Blast Furnace Slag Power in the construction field.

• Journal of Institute of Control, Robotics and Systems
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• v.2 no.1
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• pp.60-66
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• 1996

Model Based Predictive Control(MBPC) has been widely used in predictive control since 80's. GPC[1] which is the superset of many MBPC strategies a popular method, but GPC has some weakness, such as insufficient stability analysis, non-applicability to internally unstable systems. However, CRHPC[2] proposed in 1991 overcomes the above limitations. So we chose RHPC based on CRHPC for electric furnace control. An electric furnace which has nonlinear properties and large time delay is difficult to control by linear controller because it needs nearly perfect modelling and optimal gain in case of PID. As a result, those controls are very time-consuming. In this paper, we applied RHPC with equality constraint to electric furnace. The reults of experiments also include the case of RHPC with monotonic weighting improving the transient response and including unmodelled dynamics. So, This paper proved the practical aspect of RHPC for real processes.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.27.1-27
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• 2001

Reheating furnace is a facility of heating up the billet to desired high temperature in the hot charge rolling process and it consists of 3 zones. Temperature control of reheating furnace is essential for successful rolling performance and high productivity. Mostly, temperature control is carried out using PID controller However, the PID control is not effective due to the nonlinearity of the reheating furnace(i.e, presence of the interference of neighboring zones and slow response of temperature etc.). In this paper, feedback linearization method is applied to obtain a linear model of the reheating furnace. Then, controller is designed using simple predictive control method. The effectiveness of this strategy is shown through simulations.

• Journal of Magnetics
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• v.21 no.2
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• pp.204-208
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• 2016

This paper demonstrates the key parameter detection for smelting of submerged arc furnace (SAF) based on magnetic field radiation. A magnetic field radiation model for the inner structure of SAF is established based on relative theory of electromagnetic field. A simple equipment of 3D magnetic field detection system is developed by theoretical derivation and simulation. The experiments are carried out under the environment of industrial field and AC magnetic field generated by electrode currents and molten currents in the furnace is reflected outside of the furnace. The experimental results show that the key parameters of smelting including the position of electrode tip, the length of electric arc, and the liquid level of molten bath can be achieved. The computed tomography for SAF can be realized by the detection for smelting.