• 한국전산유체공학회지
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• 제21권1호
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• pp.110-116
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• 2016

The present study numerically investigated the deformation of the interface of two-phase fluids flow in a blast furnace. To simulate three-dimensional(3D) incompressible viscous two-phase flow in the furnace filled with the air and molten iron, the volume of fluid(VOF) method based on the finite volume method has been utilized. In addition, the porous medium with the porosity has been considered as the bed of the particles such as cokes and char etc. For the comparison, the single phase flow and the two-phase flow without the porosity have been simulated. The two-phase flow without porosity condition revealed the smooth parabolic profile of the free surface near the outlet. However, the free surface under the porosity condition formed the viscous finger when the free surface was close to the outlet. This viscous finger accelerated the velocity of the free surface falling and the outflow velocity of the fluids near the outlet.

• Geomechanics and Engineering
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• 제3권3호
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• pp.207-218
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• 2011

This article describes laboratory research done on strength evaluations for stabilized samples made of tropical fibrous peat. The stabilizing agents used were ordinary Portland cement (OPC) as binding agent and blast furnace slag (BFS) as additive. Stabilized samples were tested for their strength through unconfined compressive strength (UCS) and California bearing ratio (CBR). Different dosage rates of OPC and BFS were used in trial and error experiments for the most effective combination for stabilized peat samples that were at their natural moisture content. Stabilized trial samples were air cured for 90 days. After detecting the most effective dosage rate in the trial samples, their values were used to prepare CBR samples at their optimum moisture content (OMC). CBR samples were then air cured from 1 to 90 days and tested under un-soaked and soaked conditions. The most effective dosage rate for the stabilized peat samples was found to be close to when 75% for OPC and 25% of BFS per total weight of OPC, and BFS. As an example, if 11.25% OPC, and 3.75% BFS are mixed with peat and compacted at their OMC and air cured for 90 days, stabilized peat will have an increase in CBR of 0.8% to 45 % for un-soaked and 20% for soaked conditions.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.398-403
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• 2001

There is a potential usability of electric arc furnace(EAF) dust produced during the iron manufacturing process as a recycled resource, because valuable materials such as Zn, Pb and Fe are contained in it. In this study, metallic Zn was recycled from the fine electric arc furnace dust by a solid state reduction method using carbon at relatively low temperature. It was possible to recover metallic zinc by using of high vapour pressure of zinc with this reduction method. The feasibility of recycled zinc for cold bonded pellet(CBP) was investigated. The main composition of EAF dust were franklinite(ZnFe$_2$O$_4$), magnetite(Fe$_3$O$_4$) and zincite(ZnO), and Pb and Cl were completely removed by a heat treatment in oxidation environment. The reduction ratio increased as the solid carbon content increased, and it increased with decreasing of dust particle size and increasing of compaction pressure due to a increase of contact area.

• 한국결정성장학회지
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• 제22권3호
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• pp.152-157
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• 2012

본 연구는 알칼리 활성화제로 NaOH와 물유리를 사용하고 리젝트애쉬와 고로슬래그를 혼합하여 지오폴리머를 제조하였다. 리젝트애쉬와 고로슬래그의 치환율과 물유리와 NaOH의 농도에 따른 압축강도를 측정하였다. 압축강도 측정결과로는 알칼리 활성화제로 NaOH 1 wt%, 물유리 3 wt%와 전량 고로슬래그를 사용한 경우 재령 28일차 강도가 38.91 MPa의 성능을 나타내었다. 압축강도 증진의 중요한 요인은 알칼리 활성화제의 비율과 리젝트애쉬와 고로슬래그의 치환율에 의한 것이었다.

• 한국세라믹학회지
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• 제48권6호
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• pp.610-616
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• 2011

The effect of curing temperature on basic geopolymeric reactivity and hardening behaviour of blast furnace slag were investigated using the mixture of pulverized slag and several alkaline solutions of relatively high concentration. For the pastes prepared at several different temperatures between 20$^{\circ}C$ and 90$^{\circ}C$, setting time and heat of reaction were examined while mineralogical and morphological examinations were performed for the hardened paste after curing period at same temperature. The geopolymeric reaction of slag was revealed to be accelerated strongly according to the curing temperature regardless of the sort and concentration of the alkaline solution. The increase of concentration of the alkaline solution within 9M and the existence of silicic ion in the solution also promoted the reaction severely. The mineral component and their ratio of the hardened paste were revealed to be influenced by the chemical species and silicic ion contained in alkaline solution rather than by the curing temperature. The higher temperature and longer period of curing stage were effective for the sustained formation of geopolymer and succeed improvement of density and uniformity of morphology of the final hardened body.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.1112-1113
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• 2015

In the end of 2014, Changwon National University and TECHSTEEL Co., Ltd. had initiated a project on the development of a 300 kW-class HTS DC Induction Furnace(HTS DC IF) for preheating non-ferrous metal billets funded by the Korea Institute of Energy Technology Evaluation and Planning for 3 years. This is the one of the most realistic commercial machines applying the coated conductors. In this paper, the development progress of a 300 kW-class HTS DC IF was introduced. The major characteristics of the furnace including its capacity, structure and operation scheme were presented. For ensuring the successful design, a pre-validation study was performed through the electromagnetic, heat transfer and solid mechanical analysis using a multi-physics FEM tool. The aluminum billet was heated up to $540^{\circ}C$ under 1 T of the magnetic flux density at the center of the billet, and the simulation results were described in detail.

• Journal of Advanced Marine Engineering and Technology
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• 제30권8호
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• pp.870-876
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• 2006

In proportion to the increase of industrial development, emission troubles were concerned as global issue. For these reasons, so many researchers and associated institutes effort to reduce pollution with new technology and various devices. As a kind of these methods, we used catalysts as a after-treatment system. At first, we made equipment of model furnace. And various catalysts were equipped at exhaust duct of combustion system, and excess air ratio(a), change cell numbers catalyst materials(Pt, Pd) were changed as experimental conditions. With these various condition, temperature. NOx, CO, HC, $CO_2$ and $O_2$ concentration were measured. As a result, NOx conversion increased with increasing of cell number in Pd catalyst. And Pt catalyst became 100% conversion at 200 and 300 cell. Also, Pt catalyst was better than Pd catalyst at a=1.5 in this condition. In addition, CO and HC concentrations were decreased at a = 1.5 with Pd catalyst.

• 대한기계학회논문집B
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• 제28권5호
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• pp.501-509
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• 2004

Unipolar diffusion charging of non-spherical particles was investigated for various particle shapes. We researched with TiO$_2$agglomerates produced by the thermal decomposition of titanium tetraisopropoxide (TTIP) vapor. TTIP was converted into TiO$_2$, in the furnace reactor and was subsequently introduced into the sintering furnace. Increasing the temperature in the sintering furnace, aggregates were restructured into higher fractal dimensions. The aggregates were classified according to their mobility using a differential mobility analyzer. The projection area and the mass fractal dimension of particles were measured with an image processing technique performed by using transmission electron microscope (TEM) photograph. The selected aggregates were charged by the indirect photoelectric-charger and the average number of charges per particle was measured by an aerosol electrometer and a condensation particle counter. For the particles of same mobility diameter, our results showed that the particle charge quantity decreases as the sintering temperature increases. This result is understandable because particles with lower fractal dimension have larger capacitance and geometric surface area.

• 대한기계학회논문집B
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• 제25권5호
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• pp.660-665
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• 2001

Ultrafine particles have been widely used in many high technology industrial areas. The spherical nonagglomerated and uniform nanometer-size SiO$_2$particles are synthesized by the direct injection of TEOS(Tetraethyorthosilicate) using electro-hydrodynamic spraying method. Electro-hydrodynamic spraying can generate submicron-size TEOS droplets having high electric charges by applying a high electric field between the liquid injection nozzle and the reaction tube. These TEOS droplets are evaporated, and thermally decomposed or oxidized to produce nanometresized SiO$_2$particles in the reaction tube. Spherical, nonagglomerated and ultrafine particles are generated in various conditions and examined by using SEM and SMPS. As the total gas flow rate in the furnace changes from 1.5 lpm, the mean diameter of SiO$_2$particle decreases from 120 nm to 68 nm. The synthesized particle charging fractions are also investigated.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2005년도 전기학술대회논문집
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• pp.154-159
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• 2005

In proportion to the increase of industrial development, emission troubles were concerned as global issue. For these reasons, so many researchers and associated institutes effort to reduce pollution with new technology and various devices. As a kind of these methods, we used catalysts as a after-treatment system. At first, we made equipment of model furnace. And various catalysts were equipped at exhaust duct of combustion system, and excess air ratio( ), change cell numbers, catalyst materials(Pt, Pd) were changed as experimental conditions. With these various condition, temperature, NOx, CO, HC, $CO_2$ and $O_2$ concentration were measured. As a result, NOx conversion were increased with increasing of cell number in Pd catalyst. And Pt catalyst were became 100% conversion at 200 and 300 cell. Also, Pt catalyst was better than Pd catalyst ${\alpha}$=1.5 in this condition. In addition, CO and HC concentrations were decreased${\alpha}$=1.5 with Pd catalyst.