Flow Characteristics of Gas and Fine Particles in a Two-dimensional Space of Packed Bed

Yamaoka, Hideyuki

doi:10.2355/tetsutohagane1955.72.16_2194

Cited by 25 publications

(16 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In particular, a large amount of unburnt char is generated in the raceway by pulverized coal injection, and this phenomenon affects gas permeability. Therefore, since the 1990s, motion models for fine particles have been proposed, 50,51) and completion of the 4-fluild model for motion analysis of macroscopic particle groups, changes in the void fraction, etc. have been seen.…”

Section: Modeling Of Movement Of Fine Particles By the Discrete Elemementioning

confidence: 99%

Recent Progress on Advanced Blast Furnace Mathematical Models Based on Discrete Method

et al. 2014

View full text Add to dashboard Cite

From the backgrounds of the recent trends towards low reducing agent operation of large blast furnaces and application of diversified charging modes for various burdens, an advanced mathematical model of the blast furnace is required. Although conventional models based on the continuum model have been widely used, these models are not sufficient for the recent demands. Discrete models such as discrete element model (DEM) and particle method are expected to enable precisely simulation of the discontinuous and inhomogeneous phenomena in the recent operating conditions. With discrete models, microscopic information on each particle in the packed bed can be obtained in addition to the overall phenomena in the blast furnace. Visual information for understanding in-furnace phenomena can be also obtained with high spatial resolution. Liquid dripping and the movement of fines in the lower part of the blast furnace can be simulated with high accuracy by using DEM and particle methods such as the Moving Particle Semi-implicit Method (MPS). Moreover, the optimum bed structure for low reducing agent operation is being clarified by application of the Eulerian-Lagrangian method. This review summarizes recent progress on the mathematical models based on the discrete model. KEY WORDS: ironmaking; blast furnace; mathematical model; discrete model; discrete element method; particle method.

show abstract

Section: Modeling Of Movement Of Fine Particles By the Discrete Elemementioning

confidence: 99%

Recent Progress on Advanced Blast Furnace Mathematical Models Based on Discrete Method

et al. 2014

View full text Add to dashboard Cite

show abstract

“…96) These fines, if not consumed, exist in the furnace as static or dynamic holdup. Previous studies on the flow characteristics of powder in 1D and 2D geometries aimed to i) identify the relationship between pressure loss, powder holdup and powder/gas feed rate 8,11,[97][98][99] ; ii) develop the interaction force between powder and solid particles which is widely accepted in the subsequent continuous modelling 38,40,41) ; iii) examine some special phenomena such as blockade 8) and hanging. 23) Deficiencies in these studies are inherited in mathematical modelling, including, for example, the ignorance of the static holdup, the use of a relatively simple packing structure, and different interaction force equations.…”

Section: Gas-powder Flowmentioning

confidence: 99%

“…The review summarized the formulation of continuum models for four fluid flow, extended from the previous models for single-, two-and three-phase flows. With appropriate setting of the initial and boundary conditions, some of these models demonstrated the ability to describe the macroscopic flow behaviour including, e.g., the solid flow in the BF shaft, [3][4][5][6] the dilute powder flow [7][8][9][10][11][12] and liquid flow 4,[13][14][15] in a simplified BF. It also demonstrated the limitation of the models in describing the strong localized flow in regions such as raceway and cohesive zone and in extracting microscopic information to establish constitutive relations for solid flow and interactions between some phases, e.g.…”

Section: Introductionmentioning

confidence: 99%

Modelling of Multiphase Flow in a Blast Furnace: Recent Developments and Future Work

et al. 2007

View full text Add to dashboard Cite

An ironmaking blast furnace is a complex multiphase flow reactor involving gas, powder, liquid and solid phases. Understanding the flow behaviour of these phases is of paramount importance to the control and optimization of the process. Mathematical modelling, often coupled with physical modelling, plays an important role in this development. Yagi 1) gave a comprehensive review of the early studies in this area in 1993. Significant progress has since been made, partially driven by the needs in research but mainly as a result of the rapid development of computer and computational technologies. This paper reviews these developments, covering the formulation, validation and application of mathematical models for gas-solid, gas-liquid, gas-powder and multiphase flows. The need for further developments is also discussed.KEY WORDS: ironmaking; blast furnace; multiphase flow; two fluid model; discrete element method. Review development. Mathematical ModellingGenerally speaking, the existing approaches to modelling the multiphase flow in a BF can be classified into two categories: continuum approach at a macroscopic level and discrete approach at a microscopic level. In the continuum approach, phases are generally considered as fully interpenetrating continuum media and described by separate conservation equations with appropriate constitutive relations and interaction terms representing the coupling between phases. The general governing equations are based on the so-called two fluid model (TFM), originally developed for gas-particle flow, [29][30][31] given by:Conservation The so-called Model A and Model B result from the treatment of the fluid pressure. For example, for gas-solid flow, Model A assumes the pressure is shared between the two phases, while in Model B, the pressure is attributed to gas phase only. 31) Model A formulation has been widely used in multiphase modelling, especially in process metallurgy. Model B formulation was recently used in the so called combined continuum and discrete method for coupled flow of continuum fluid and discrete particles. 32) The continuum approach is suitable for process modelling and applied research because of its computational convenience and efficiency. Indeed, most of the BF modelling is based on this approach. However, its effective use heavily depends on constitutive or closure relations and the momentum exchange between phases. For Newtonian fluids (gas and liquid here), these relations can be readily determined. For non-Newtonian fluids such as solids and powder, general theories are not yet available. In the past, various theories have been devised for different flow regimes (three flow regimes have been identified: quasi-static regime, rapid flow regime and a transitional regime that lies inbetween). For example, models have been proposed to derive the constitutive equations for the rate-independent deformation of granular materials based on either the plasticity theory or the double shearing theory; the rapid flow of granular materials has been described by extend...

show abstract

“…Fundamental flow mechanics such as traveling velocity of powders and interaction forces among gas, fine powders and packed particles were measured, and mathematical models based on these works were proposed. [9][10][11][12][13][14][15][16] Although these models successfully simulated powder motion and pressure drop within packed beds, all models except for Yamaoka's work 16) treat powders as dynamic hold-up or moving total hold-up, and are incapable of taking into account static hold-up and accumulation behavior. The authors have developed mathematical models of blast furnace, which are based on multi-fluid theory.…”

Section: Introductionmentioning

confidence: 99%

Numerical Analysis on Behavior of Unburned Char and Fine Coke in Blast Furnace

2005

View full text Add to dashboard Cite

A mathematical model of blast furnace operation, which is able to estimate the behaviors of the unburned char and the fine coke simultaneously, has been developed. The model based on the multi-fluid theory treats dynamic powders that are moving entrained by the gas stream as individual phases and static powders as solid components. The former takes conservation equations of momentum, thermal energy, chemical species and continuity. The latter takes only mass balance equations of chemical species, and shares fields of flow and temperature with the other solid components, such as lump coke, sinter, and so on. In the simulations, the unburned char is derived from the pulverized coal injected from the tuyere, and there is no difference in model treatment between the unburned char and the pulverized coal. The fine coke is generated uniformly in the raceway region from the coke particles, and the generation rate is determined by a kinetic treatment. The simulation of the blast furnace operation by this model revealed that the unburned char and the fine coke having different diameters and densities show different flow patterns especially in the cohesive zone and deadman. Consequently these two powders formed different areas of accumulation and reactions while large amount of powders were deposited in the deadman zone regardless of difference in flow patterns.

show abstract

Flow Characteristics of Gas and Fine Particles in a Two-dimensional Space of Packed Bed

Cited by 25 publications

References 1 publication

Recent Progress on Advanced Blast Furnace Mathematical Models Based on Discrete Method

Recent Progress on Advanced Blast Furnace Mathematical Models Based on Discrete Method

Modelling of Multiphase Flow in a Blast Furnace: Recent Developments and Future Work

Numerical Analysis on Behavior of Unburned Char and Fine Coke in Blast Furnace

Contact Info

Product

Resources

About