Similarity Model for DEM Simulation of Fluidized Bed

Shaft gas injection of reducing gas in the blast furnace is one of favorable ways to greatly decrease CO2 emissions from steel works, and this approach is used for the top gas recycling and oxygen blast furnace processes. In these processes, the penetration effect of the gas injected from the auxiliary tuyeres is important for attaining effective gas reduction or making up the heat balance in the upper part, and so it is useful to analyze the dynamic behavior of the gas injected into the shaft. In the present study, the penetration effect of injected gas was three-dimensionally simulated by a hybrid model of the discrete element method (DEM) and continuum model (CFD). In particular, the CFD model was used to quantitatively analyze the dynamic gas flow and the pressure distribution in the burden layers calculated by DEM. Although the area influenced by the injected gas from the auxiliary tuyeres was restricted to a specific area due to insufficient horizontal inertial force of the gas, the penetration area gradually enlarged as the gas velocity from the auxiliary tuyeres increased. In a small blast furnace, the injected gas can easily reach the center with the higher gas velocity, and it was shown that the relative penetration depth of the injected gas depends on the inner volume of the blast furnace. However, the overall behavior of the injected gas did not show any remarkable change. In conclusion, the penetration area of shaft gas was almost proportional to the ratio of shaft gas and the upward gas from the conventional tuyeres.

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“…The pressure drop is expressed by the multidimensional Ergun's equation for a packed bed. : [13][14][15][16][17] ...…”

Section: Structure Of Present Modelmentioning

confidence: 99%

Penetration Effect of Injected Gas at Shaft Gas Injection in Blast Furnace Analyzed by Hybrid Model of DEM-CFD

et al. 2011

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“…Because of the huge particle numbers and limited computation capacity, the particle diameter is set as 350 µm, which is around five times the real particle diameter. Then, in order to keep the similarity of flow in the simulation, a correlation model proposed by Washino et al [19] has been used to adjust the simulation conditions, such as the superficial velocity, gas density, gas viscosity and particle density. The time step for simulation is calculated as follows [15]:…”

Section: Simulation Conditionsmentioning

confidence: 99%

ECT measurement and CFD–DEM simulation of particle distribution in a down-flow fluidized bed

Zhao

Takei

Doh

2010

Flow Measurement and Instrumentation

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“…In these models, large-sized particles are used instead of groups of the original particles. The models are called the similarity model [14], the imaginary sphere model [15] and the representative particle model [16]. These models were developed by focusing on the drag force for the simulation of fluidized beds, where the particle-fluid interaction force is larger than the other forces.…”

Section: Introductionmentioning

confidence: 99%

“…Some models have been developed through large-scale modeling using the DEM [14][15][16]. These models have the common principle that the simulations should be performed by using as small a number of particles as possible.…”

Section: Introductionmentioning

confidence: 99%

Large‐scale discrete element modeling in a fluidized bed

Sakai

Yamada

Shigeto

et al. 2010

Numerical Methods in Fluids

110

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SUMMARYThe discrete element method (DEM) is widely used in calculating powder systems. The DEM makes it possible to determine the complicated phenomena related to particle flowability. However, DEM has a fatal problem, which is that the number of calculated particles is restricted due to excessive calculation costs. Consequently, we have developed a large-scale model of the DEM, which is called the coarse grain model. The coarse grain particle represents a group of the original particles. Therefore, a large-scale DEM simulation can be performed using an extremely small number of the calculated particles. In our previous studies, the coarse grain model was applied in gas-solid and solid-liquid flow systems. It is anticipated that the coarse grain model will be used in various powder systems. In the current study, the coarse grain model has been applied to a two-dimensional bubbling fluidized bed. The adequacy of the coarse grain model was proved by a comparison with the original particle behavior. The simulation results obtained using the coarse grain model showed good agreement with the results for the original system. Moreover, the calculation speed with the coarse grain model was shown to be much faster than the calculation speed of the original model.

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Similarity Model for DEM Simulation of Fluidized Bed

Cited by 40 publications

References 9 publications

Penetration Effect of Injected Gas at Shaft Gas Injection in Blast Furnace Analyzed by Hybrid Model of DEM-CFD

Penetration Effect of Injected Gas at Shaft Gas Injection in Blast Furnace Analyzed by Hybrid Model of DEM-CFD

ECT measurement and CFD–DEM simulation of particle distribution in a down-flow fluidized bed

Large‐scale discrete element modeling in a fluidized bed

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