The aim of this research is to study heat and mass transfer in sponge iron reactor reduction zone through mathematical modeling arrangement and simulation. Kinetics equation of reduction of hematite to iron metal, methane reforming, and water gas shift reaction are taken into account in the model. After being validated with the reference data, the model is able to satisfactorily describe temperature and concentration profiles along reduction zone. The results also show that an increase in reduction gas temperature inlet will increase the metallization degree.

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We studied the effect of H₂ addition to atmosphere on reduction of carbon composite iron oxide pellets. Cokes was mixed with reagent grade hematite in the mass ratio of one to four (COKE-a) or nine (COKE-b) together with Bentonite of 1 mass% as a binder. Carbon composite pellets using cokes were prepared by handrolling. The formed pellets were reduced from room temperature to 1273 K at 10 K min^-1 in the inactive gas (Ar or N₂) atmosphere or the inactive gas atmosphere containing 10 vol% H₂. From variations of gas flow rate and weight loss curve of COKE-a in the inactive gas atmosphere containing 10 vol% H₂, it was found that the reduction of iron oxide started from 573 K by the effect of 10 vol% H₂ and accelerated from 1273 K by the effect of not 10 vol% H₂ but cokes. On the other hand, in case of COKE-b, the weight drastically decreased from 1273 K by the effect of 10 vol% H₂. Finally, the U_H2(H₂ reaction ratio) increased with decreasing the R_C(coke reaction ratio) using COKE-b.

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The influences of temperature, CaO/SiO₂ and Al₂O₃ content on the melt formation behavior of slag in FeO-CaO-SiO₂-Al₂O₃ system were investigated by a thermodynamic calculation. In-site observations of artificial iron ore agglomerates on the melt formation behavior of slag in FeO-CaO-SiO₂-Al₂O₃ system were carried out by a scanning laser microscope mounted with a heating device. It is evaluated from the thermodynamic calculation that CaO/SiO₂ and Al₂O₃ content greatly influence the amount of molten slag with high FeO. The initial melt formation shifts toward high temperature with increasing CaO/SiO₂ and with decreasing Al₂O₃ content, and the amount of melt also decreases. The melt formation behavior by the in-site observations was in reasonable agreement with the thermodynamic calculations, and therefore the thermodynamic calculation is useful to evaluate the melt formation behavior of iron ore agglomerates.

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Thermodynamic consideration of impurity removal from molten iron was conducted. Possibility and extent of impurity oxidation and evaporation was discussed. As a first step, vapor pressure of pure impurity and equilibrium oxygen partial pressure that pure impurity coexist with its oxide were calculated at steelmaking temperature for 48 elements. The results were categorized by groups in the periodic tables and the possibilities of impurity removal for each element were estimated. In the next step, more accurate estimation was conducted using the thermodynamic information of impurities in molten iron for 24 elements. The estimation could not be done for the elements that thermodynamic information in molten iron was unavailable. Estimation for the removal of some elements differed due to the effect of considering the activity coefficient in molten iron. It was made clear the removal possibility can be roughly estimated by thermodynamic consideration of pure elements. However, the thermodynamic information in molten iron is required for precise estimation.

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Removal of surface active elements in molten iron, such as copper and tin, is tried by the use of the penetration phenomena. Iron-copper(or tin) alloy is put by contact with complex oxide, CaO·Al₂O₃ or NiO·Al₂O₃, which have a good wettability with molten iron, at 1823K. Copper is removed from molten iron including sulfur when CaO·Al₂O₃ is made to contact the molten iron. The sulfur is effective for the copper removal by this method. When the sulfur content is adjusted in the range from 0.05 to 0.5 mass&, the removal ratio of 14& is attained. In the case of NiO·Al₂O₃, the copper can be removed even for Fe-Cu metal which contains no sulfur, and the maximum copper removal ratio of 20& is attained. The tin removal ratio increases with the increase of sulfur content for both cases that CaO·Al₂O₃ and NiO·Al₂O₃ are used and increases from 2 to 37& for CaO·Al₂O₃ and from 28 to 53& for NiO·Al₂O₃. In this work, it is found that both copper and tin in molten iron can be removed by contact with CaO·Al₂O₃ or NiO·Al₂O₃.

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The evolution of as-cast γ grain in low carbon steel has been investigated using thin slab cast simulator. Fine columnar γ grain evolved from the surface to the center of the ingot was obtained, and second dendrite arm spacing was investigated. The γ grain size for the present cooling rate of approximately 2˜20 K/s showed a relatively good agreement with the estimated value by the previously predicted line of d _γ =1.52γ^-0.5 for low carbon steels based on the Classical Grain Growth Model (CGGM). The effect of some elements was examined and it was proved that ferrite stabilizing elements such as phosphorus and tin have great effect of reduction of austenite grain size and copper has little effect on it. On the basis of the effect obtained, guiding principles for the control of the as-cast microstructure have been found.

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A utilization of Fe as an additive in smelting reduction of Pb glass was proposed in this work with the aim of detoxification treatment of Pb glass, where Pb is removed from the glass. In the present experiment, Pb glass contained in Fe crucible was melted with Fe lump at 1300 °C under Ar atmosphere for 3 hr. It was found that added Fe can reduce PbO in PbO glass to metal Pb and, in addition, the FeO introduced by the reaction Fe + PbO = Pb + FeO works as a melting agent lowering the viscosity of glass, which promotes the separation of Pb from Pb glass in smelting reduction.

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It is known that small quantities of surfactant additives can greatly reduce the friction factors during the flow of a heat transfer medium. The friction factors are reduced because the generation of turbulent vortices is suppressed by the formation of rod-like micelles, and the flow remains laminar in the high Reynolds number range. However, the values of heat-transfer coefficients decrease during flow laminarization; as a result, heat exchangers with a larger heat transfer area are required. The objective of this research is to study the heat transfer enhancement effect of microbubble injection. This paper presents an experimental investigation of the heat transfer and flow characteristics of the two-phase flow of an air-surfactant solution through a horizontal pipe. In the experiment, microbubbles were injected through three types of porous metal. The experimental results are as follows: The size of the bubbles in a bubbly flow decreases with an increase in the filtering accuracy of a porous metal. The flow patterns of the two-phase flow of an air-surfactant solution depend on the size of the microbubbles. The heat-transfer coefficient is promoted by microbubbles injection, but the effect depends on the flow pattern or the size of microbubbles. If the diameter of the microbubbles is approximately 100 μm, there is little enhancement in heat-transfer, but a remarkable enhancement in heat transfer is observed when the diameter of the microbubbles is approximately 400 μm or more.

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Inorganic materials, such as monolithic ceramics, graphite and ceramic based composites, are expected for the material of structural parts used in high-temperature ambience. In this study, inorganic adhesives are adopted to bonding material for heat resistant joint of metals, and are also used for matrix of heat resistant composites. The inorganic adhesives used in the present study can be cured at 150°C and the maximum temperature resistance proposed is up to 1200°C. To establish the joining technology, we measured the elastic modulus of the bulk specimens and the composite specimens filled with aluminum particles and the bond strength at elevated temperatures up to 700°C. The experimental results of Young's modulus of the bulk specimens obtained by a dynamic flexural test are slightly decreased with heating from a room temperature (RT) to 500°C. However, the damping of free vibration of the specimen is increased remarkably from 500°C to 700°C. Young's moduli of the composite specimens with aluminum contents of 20% to 50 % show good stability reversibly in heating process up to 600°C and cooling process to RT. The strengths of the joints obtained by a push-out test are increased with temperature rise to 500°C and remarkably decreased with heating more that temperature. This paper mentioned the aluminum filler is effective to enhance the property of these types of inorganic adhesives up to 500°C.

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The purpose of this study is to investigate the behavior of a transient powder-laden liquid jet coaxially injected into a pipe flow. The visualization techniques adopted include a high-speed camera and computational fluid dynamics. The equivalent diameter and density of the adopted powder are 700nm and 2700kg/m³, respectively. The computation also simulates the present target flow against the experiment, based on the one-way coupling for the particle movement. As a result, the spreading angle and centerline velocity of the transient particle-laden jet are given between the experiment and computation.

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Whole-space tabulation method is a technique to relate phase of projected grating with coordinates of the corresponded point pixel by pixel. The relation data are stored in a table. Thereby, high speed and accurate shape measurement is realized. In this paper, a memory board for whole-space tabulation method was developed. An experiment to evaluate this board was performed. The shape measurement speed using the memory board was higher than using software. The shape measurement accuracy using the memory board was the same as using software.

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A new polymeric split Hopkinson pressure bar (SHPB) method is presented to study the dynamic behavior of low-strength and low-impedance materials, such as polymers and elastomers. To consider the low-impedance characteristics of test specimens, polymethyl methacrylate (PMMA) bars are used as the input and output bars. In the proposed polymeric SHPB method, the wave analysis of the strain pulses along the bars is performed in the frequency domain. Strain histories at the respective given points on the input and output bars obtained from polymeric SHPB tests are resolved into frequency components by Fourier transformation, and waveforms at the respective measurement points are corrected to those at the two interfaces between the specimen and the bars. The proposed method is applied to identify mechanical models for several low-impedance materials such as golf ball materials. The complex compliance for each material is determined as one of the dynamic viscoelastic properties in the frequency domain. Furthermore, from the FEM simulations on impact tests of a golf ball, it is verified that the proposed method provides an effective tool for modeling the dynamic behavior of low-impedance materials.

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A method for smoothing the measured displacements and computing strains utilizing a finite element method is proposed. Nodal displacement values in a finite element model are determined by fitting the interpolation function inside the elements to the measured values using the method of least-squares. Then, the smoothed displacement distributions are obtained. The displacements in the region where the measured values are not obtained or unreliable are determined by solving finite element equations. The validity is demonstrated by applying the proposed method to displacement distributions of a plate with a hole obtained by finite element analysis and those obtained by electronic speckle pattern interferometry. Results show that the strains can be computed from the measured displacements accurately by the proposed method. Furthermore, the strains near free boundaries and strain concentration region can be determined easily. As strains can be evaluated easily and accurately, it is expected that the proposed method can be applied to various problems in solid mechanics.

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The purpose of this paper is to experimentally investigate behavior of transient jet from an L-shaped nozzle in a horizontal turbulent pipe flow. The selected Reynolds numbers are 4.24 × 10³, 1.11 × 10⁴ and 1.70 × 10⁴ where the pipe flow is fully turbulent one. The preliminary computation is carried out for no jet injection case, and shows that the wake behind the nozzle forms within five times the nozzle inner diameter. Using the LDV measurement, the transient jet injected into a turbulent pipe flow is found to behave a similar one, for x › 50mm from the nozzle exit, to an axisymmetric free turbulent round jet whose centerline velocity u_cl decreases as u_cl ∼ 1/x. After the transient jet passing through a measurement point, the centerline velocities are almost identical between with and without the jet injection. In addition, this paper visualizes the transient jet to observe the jet behavior using the red food coloring.

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