Papers by Keyword: Fluidized Bed

Abstract: This work introduces an initial finite element (FE) framework for modelling particle-substrate interaction during fluidized bed surface finishing of Laser Powder Bed Fusion (L-PBF) components. Due to the complexity of as-built surface morphology and the difficulty of experimentally observing high-speed particle impacts, the mechanisms governing material removal remain poorly understood. The proposed 3D explicit FE model simulates the impact of stainless-steel particles on representative AlSi10Mg asperities using Johnson-Cook plasticity model and damage formulations. Results show that erosion occurs mainly through localized brittle-like detachment rather than extensive plastic deformation. Sequential impacts and oblique trajectories significantly increase internal energy absorption, enhancing asperity fragmentation and the surface smoothing level. The framework provides a foundation for future optimization of Fluidized Bed Finishing (FBF) parameters for improved finishing of additively manufactured metal parts.

Abstract: Co-firing Refuse Derived Fuel (RDF) from Municipal Solid Waste (MSW) with coal presents a promising approach to urban waste management and reduction of fossil fuel dependency. This study primarily investigates the optimal co-firing ratio of RDF MSW and coal, alongside other operational parameters, in a laboratory-scale fluidized bed reactor. Experiments were conducted with variations in RDF MSW to coal ratio (5%, 10%, 15%), operating temperature (750°C, 850°C, 950°C), and excess air (15%, 20%, 25%, 30%) in a reactor with a combustion chamber volume of 1000 cm³. Results demonstrate that the co-firing ratio significantly influences combustion efficiency and overall performance. The optimal ratio was found to be 10% RDF MSW with 90% coal, yielding a peak combustion efficiency of 95.89% and a minimum Specific Fuel Consumption (SFC) of 0.19260 kg/kWh. This optimal ratio balances the benefits of RDF's higher volatile content with coal's stable combustion characteristics. Additionally, an operating temperature of 750°C and excess air of 20% complemented this optimal ratio, further enhancing stability and efficiency. SEM analysis and chemical composition studies of agglomerates revealed the role of Ca, K, Na, and Mg in deposit formation, providing insights into the interaction between RDF and coal during co-firing. This research offers valuable guidance for optimizing co-firing ratios in industrial applications, supporting the development of more efficient and environmentally friendly waste-to-energy solutions.

Abstract: The liquid-solid fluidization bed is an effective method for removing hard ions from water. However, it is widely believed that the flow in the liquid-solid fluidization bed is homogeneous, which limits the transfer rates of heat, mass, momentum, and mixing. In this study, the results of the computational fluid dynamics (CFD) method showed significant heterogeneous particle–fluid patterns in the liquid-solid fluidization bed. On the other hand, simulations of the hydrodynamics behavior in the liquid-solid fluidized bed were first performed using different solid particle sizes, then particle classification, velocity distribution, and the vortical structures in the liquid-solid fluidized bed were assessed. In addition, a new model was proposed in this study to predict the flow behavior of the fluid-particle system used. The obtained results demonstrated the presence of the heterogeneous flow regime in the liquid-solid fluidized bed. The developed model for the onset of heterogeneous fluidization behavior revealed reasonable prediction results. Therefore, this model can be applied in future related studies on the hydrodynamics of the liquid-solid fluidized bed.

Abstract: The authors of the article analyzed the properties of the fluidized bed during the formation of the abrasive-polymer compound for waterjet cutting. It is noted that in the process of applying the polymer shell to the surface of the abrasive grain in the fluidized bed, the effect of slippage and the absence of the influence of the installation wall on the value of the longitudinal velocity of particles near it is observed, which allows to increase the productivity of creating an abrasive-polymer compound.

Abstract: The high-temperature synthesis of silicon carbide (SiC) in an electro-thermal fluidized bed reactor (EFB) has advantages, in comparison with the production in resistance furnaces, in terms of specific energy consumption, productivity and the level of automation of the technological process. The basic equations of the fluidized-bed carbide formation process model are presented in the paper. The results of calculating the synthesis parameters of finely dispersed SiC in the stationary operation mode of the EFB reactor are also presented. The correspondence between the calculated and available experimental results on the output of the final product is shown.

Abstract: The paper presents the results of experimental studies of strontium hexa-ferrite average particle size and structural characteristics changes during milling process. Coarse strontium hexaferrite was milled in beater mill, without and with electromagnetic effect. Electromagnetic effect was produced by constant and alternating gradient magnetic fields with mutually perpendicular induction lines. Particle sizes were measured by microscopic methods, and structural characteristics were calculated by processing of X-ray diffractograms. Diffraction studies showed that during milling process, both with and without electromagnetic effect, the most intensive changes of coherent scattering region (CSR) sizes, dislocation densities and relative deformation of particulate material occur at earlier stage of milling. At this stage the speed of average particle size decrease is maximal. At later stage both average particle size and structural characteristic changes correlate and have asymptotic character.

Abstract: Article presents an experimental study result of milling coarse strontium hexaferrite in beater mill with formation of magneto fluidized bed and without it. Magneto fluidized bed is formed by mutually perpendicular constant and alternating gradient magnetic fields. We studied the dynamics of particle size distribution from milling time and parameters of magnetic fields. Microstructure dynamics of strontium hexaferrite powder particles milled in various regimes was studied by X-ray diffraction methods. Milling efficiency and energy efficiency of milling process were studied in conditions with and without powder fluidization by magnetic fields. Analysis of experimental data showed advantages of milling in magneto fluidized bed in increased efficiency, particle size distribution homogeneity and powder chemical activity because of lattice micro-stresses.

Abstract: The paper experimentally substantiates effectiveness of method of milling particulate ferromagnetic materials in magneto fluidized bed. Comparative results of particle size distributions and structural parameters of strontium hexaferrite SrFe₁₂O₁₉ powder obtained by milling coarse material in beater mill without electromagnetic effect and in same mill with formation of magneto fluidized bed from mill material are presented. The magneto fluidized bed is formed by constant and alternating gradient magnetic fields with induction lines that are mutually perpendicular and parallel to the plane of rotating beaters. It is shown that application of electromagnetic effect to milling coarse material in beater mill allowed to greatly intensify that process, significantly increase powder quality: increase particle size distribution uniformity and decrease average particle size from 1558.50 μm to 0.56 μm after 120 minutes of processing in the mill. X-ray diffraction analysis showed that milling in beater mill in magneto fluidized bed leads to reduction of coherent-scattering region size, increase of lattice microstrain and dislocation density, making powder more active during sintering process.

Abstract: A gas-solid multiphase flow is simulated using CFD to investigate the fluid dynamics of a fluidized bed reactor. The simulation is based on Euler-Euler two fluid model where Kinetic Theory of Granular Flow is used for predicting the solid phase transport properties. The simulation procedure is validated by reproducing and comparing hydrodynamic parameters with those available in the literature. The effect of different turbulence models on bed fluid dynamics is analyzed and k-ε RNG per-phase model is found to have better prediction accuracy compared to other models. The minimum fluidization velocity, granular temperature, bed expansion, particle velocity and volume fraction are determined by the model.

Abstract: This article analysis the computational simulation of wood's gasification in a bubbling fluidized bed reactor. Most articles about this topic, on homogenous reactions, don’t consider methane reforming. However, this article has taken this into consideration in the process of gasification. The bubbling fluidized bed reactor was used in the simulation, in which the advantages of a good mixture is presented, one which provides high rates of mass and heat transfer. The gas-solid flow that occurs in this reactor was described through mass, energy, momentum, and chemical species balances. The model used for the simulation was the computational fluid dynamics (CFD), by means of an open-source program named MFIX (Multiphase Flow with Interphase eXchange). It is concluded that methane reforming is important in the process of gasification.