Simulation of Sintering Process -Effects of Air Flow, Liquid Film Cohesion Force and Fixation Process on Large Scale Crack-

Yuu, Shinichi; Umekage, Toshihiko; Ishiyama, Osamu

doi:10.2355/isijinternational.52.1785

Cited by 6 publications

(4 citation statements)

References 7 publications

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“…8) Others are shown in Nomenclature. Yuu et al 4,5) present the detail of the similar computational procedure in the journal. See the reference 5 for the detail.…”

Section: Particle Calculationmentioning

confidence: 99%

Simulation of Sintering Process – Effects of Contraction Force by Particle Shrinkage and Melted Particle Volume on Growth of Void and Crack –

Yuu¹,

Umekage

2013

ISIJ Int.

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The particle and the air motions in the nearly full scale sintering bed have been simulated to elucidate the void (crack) formation mechanism and the crack growth mechanism. The simulation results showed that the contraction force produced the large scale cracks in the wide area in the fixation zone above the melting zone. Since the contraction force acts toward the particle center from each contact point, the resultant force in the inhomogeneous configuration of contact point moves the particles in the melted liquid. This migration produced the agglomerate which grew continuously. The bed weight in the sintering particle bed disrupted the large agglomerate. Through the process the cracks (voids) further grew and merged to a large scale crack. Large scale cracks developed taking account of the contraction force well represented the measured large scale cracks in the full scale sintering bed obtained using CT scan. In the case that the liquid volume produced by melting was large such as 88% of particle volume, the distance between the neighboring particles in the melted liquid became large and the liquid film between particles became thick. Thus it became hard for particle to move by the resistance force in the liquid. Therefore the agglomerate and the void did not grow to the large scale crack. The agglomeration of particles for 88% of particle volume melted was not so fast that the sintering bed in which the agglomerate particles uniformly distributed was formed.

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“…8) Others are shown in Nomenclature. Yuu et al 4,5) present the detail of the similar computational procedure in the journal. See the reference 5 for the detail.…”

Section: Particle Calculationmentioning

confidence: 99%

Simulation of Sintering Process – Effects of Contraction Force by Particle Shrinkage and Melted Particle Volume on Growth of Void and Crack –

Yuu¹,

Umekage

2013

ISIJ Int.

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“…Агломераційний та доменний процеси пов'язані з просмоктуванням або продуванням газів через шар. Кількість кисню, підведеного до зони горіння твердого палива у шарі, визначає швидкість горіння палива, а кількість і температура відхідних із зони горіння газоподібних продуктів реакцій -швидкість зростання температури в шарі шихти [1].…”

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“…Формула (1) призначена для розрахунку втрат тиску в циліндричних трубах і заснована на доповненні формули Вейсбаха коефіцієнт Дарсі опору ділянки труби довжиною L і діаметром D [5,6]:…”

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Influence of valve effect on energy efficiency of layer gasdynamic systems

Krivenko

2021

Bull. Nat. Tech. Univ. "KhPI". Ser.: Energy: Reliab. Energy Eff

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The direction of gas movement and the properties of the granular layer, which must be taken into account in the Darcy-Weisbach formula, have a significant effect on the energy efficiency of gas-dynamic processes in layered systems. The complex form of the regularity of the coefficient of resistance from the content of fine fractions in the layer is justified by the wavy shape of the channels in which the fine fractions are located. However, this phenomenon can be justified by the forced migration of small particles inside the cavities of the layer under the influence of mobile gases. The influence of the mobility of particles during air blowing of separated and mixed granular layers on the coefficient of gas-dynamic resistance is investigated. A smooth decrease in the value of the coefficient with an increase in the air flow rate before the transition of the layer to the fluidization mode was observed for monofraction layers. Fractures, caused by the formation of a low-permeability area due to the placement of small fractions in narrow places between large ones, have been identified for the separated layers. The presence of such a fracture depends on the ratio of particle sizes and their roughness. The increase in pressure under the bed allows the fines to gradually move upward through the voids between the larger fractions. A layer of small balls formed on top and the pressure loss in the entire steel layer is about twice as high as for the separated layer. This is due to the fact that the small balls completely fill the voids between the large pellets and the total height of the column of balls in the channels of the layer has approximately doubled in relation to the initial filling height. In addition, the tortuosity of the channels between large pellets, through which air passes, increases, which contributes to an increase in the gas-dynamic resistance to the layer. An abrupt transition to a "fluidized" bed is observed for a monofractional charge of small balls at a critical gas pressure drop, pressure pulsations occur ±100 Pа and consumption ±0,365·10–3 m3/s. A spontaneous sharp drop in the drop occurs after the formation of geyser channels. The rigid structure of the layer, characteristic of the agglomeration process, ensures uniform movement of gases in the layer, but the valve effect occurs when the content of fine fractions in the layer is more than 3.1 % and increases the energy consumption for the movement of gases in the layer by 30 %. The placement of two or more particles in such cavities between large and retained in them due to friction forces occurs in this case. Elimination of the low-permeability barrier will increase the height of the dormant layer from 400 to 550–600 mm and reduce the consumption of solid fuel of the charge by 10–15 % due to its redistribution along the height.

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“…Computer simulation by DEM (Discrete Element Method) has been introduced in iron making processes. Ramos et al 6) and Yuu et al 7) have applied DEM simulation to the sinter bed shrinking during sintering. Soda et al 8) have applied to granulation in continuous drum mixer.…”

Section: Introductionmentioning

confidence: 99%

DEM Simulation of Collapse Phenomena of Packed Bed of Raw Materials for Iron Ore Sinter during Charging

et al. 2013

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The collapse phenomena like an avalanche of sinter bed during charging of raw materials in the iron ore sintering are often observed. The collapse phenomena strongly influence the size segregation of raw materials in sinter bed, permeability and productivity of sinter. The reasons why collapse phenomena of the sinter bed during charging occur in the iron ore sintering have been discussed using the simulation by DEM (Discrete Element Method) in this work. As factors causing the collapse phenomena, there could be the granule shape of raw materials charged and the adhesion between the granules. First of all, a simulation model which is considered the adhesion force between the granules has been developed. The charging behavior of raw materials on the sintering machine was simulated by DEM. Effects of the adhesion force on deposition and collapse phenomena of the sinter bed were investigated. The deposition angle of the sinter bed obviously increases and the collapse phenomena of granules are clearly observed when the adhesion force was introduced into the granules. The ridges on the surface of the sinter bed which are feature of the collapse phenomena are confirmed. Therefore one of the reasons why the collapse phenomena occur during charging of the raw materials into the sintering machine would be adhesion of granules.

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Simulation of Sintering Process -Effects of Air Flow, Liquid Film Cohesion Force and Fixation Process on Large Scale Crack-

Cited by 6 publications

References 7 publications

Simulation of Sintering Process – Effects of Contraction Force by Particle Shrinkage and Melted Particle Volume on Growth of Void and Crack –

Simulation of Sintering Process – Effects of Contraction Force by Particle Shrinkage and Melted Particle Volume on Growth of Void and Crack –

Influence of valve effect on energy efficiency of layer gasdynamic systems

DEM Simulation of Collapse Phenomena of Packed Bed of Raw Materials for Iron Ore Sinter during Charging

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