The Use of CFD Technique in the Study of the Spouted Bed

2006 ◽  
Vol 530-531 ◽  
pp. 382-387 ◽  
Author(s):  
Claudio Roberto Duarte ◽  
R.A.A. Rosa ◽  
Valéria V. Murata ◽  
Marcos A.S. Barrozo
Keyword(s):  
Flow Pattern ◽  
Gas Flows ◽  
Present Calculation ◽  
Multiphase Model ◽  
Catalytic Polymerization ◽  
Spouted Bed ◽  
Qualitative And Quantitative ◽  
Eulerian Multiphase Model ◽  
Good Agreement ◽  
Circulation Characteristics

The spouted bed has been used in drying, granulation, catalytic polymerization, residues treatment and coating of several materials. The success of its applications is attributable to the solids circulation characteristics and excellent gas-particle contact. The pattern of solid and gas flows in a spouted bed was numerically simulated using a Eulerian multiphase model. The typical flow pattern of the spouted bed was obtained in the present calculation for axisymetric gas-solid flows. The simulated velocity profiles and the voidage profiles presented a good agreement qualitative and quantitative with the experimental results obtained by He et al. [4].

Simulation of Spouted Bed Using a Eulerian Multiphase Model

2005 ◽  
Vol 498-499 ◽  
pp. 270-277 ◽  
Author(s):  
Claudio Roberto Duarte ◽  
Valéria V. Murata ◽  
Marcos A.S. Barrozo
Keyword(s):  
Control Volume ◽  
Flow Behavior ◽  
Cfd Modeling ◽  
Gas Flows ◽  
Present Calculation ◽  
Multiphase Model ◽  
Spouted Bed ◽  
Particle Coating ◽  
Spouted Beds ◽  
Good Agreement

Spouted bed systems have emerged as very efficient fluid-particle contactors and find many applications in the chemical and biochemical industry. Some important applications of spouted beds include coal combustion, biochemical reactions, drying of solids, drying of solutions and suspensions, granulation, blending, grinding, and particle coating. An extensive overview can be found in Mathur and Epstein[1]. The pattern of solid and gas flows in a spouted bed was numerically simulated using a CFD modeling technique. The Eulerian-Eulerian multifluid modeling approach was applied to predict gas-solid flow behavior. A commercially available, control-volume-based code FLUENT 6.1 was chosen to carry out the computer simulations. In order to reduce computational times and required system resources, the 2D axisymmetric segregated solver was chosen. The typical flow pattern of the spouted bed was obtained in the present calculation. The simulated velocity and voidage profiles presented a good agreement qualitative and quantitative with the experimental results obtained by He et al. [4].

Effective numerical model for flow boiling of a nanofluid

2017 ◽  
Vol 7 ◽  
Author(s):  
Anurag Alam Shetty ◽  
Pradyumna Ghosh ◽  
S. S. Mondal ◽  
Nirupama S. Patra. ◽  
R. S. Singh
Keyword(s):  
Heat Transfer ◽  
Flow Boiling ◽  
Nucleate Boiling ◽  
Multiphase Model ◽  
Heat Transfer Characteristics ◽  
Two Phase ◽  
Ansys Fluent ◽  
Phase Mixture ◽  
Eulerian Multiphase Model ◽  
Good Agreement

Flow boiling of Al2O3-Water nanofluid has been investigated numerically using the Eulerian multiphase model in ANSYS FLUENT. The physical properties have been computed using the two phase mixture model. In the Eulerian multiphase model, Rensselaer Polytechnic Initiative (RPI) nucleate boiling model has been used for modeling boiling. Axial vapor fraction has been computed in case of flow boiling of water and heat transfer coefficient has been computed in case of flow boiling of Al2O3-Water nanofluid. The numerical results obtained were in good agreement with experimental results. The RPI model predicts the heat transfer characteristics quickly.

Fluid Dynamic Study of the Fluidized Bed Wit Jambu Seeds (Sphilantes oleracea L.)

2010 ◽  
Vol 660-661 ◽  
pp. 413-418
Author(s):  
R.O. Lourenço ◽  
C.M.L. Costa ◽  
Cristina dos Santos Rocha Sandra ◽  
A.L.A. Mesquita ◽  
E.N. Macêdo
Keyword(s):  
Fluidized Bed ◽  
Fluidized Beds ◽  
Fluid Dynamic ◽  
Characteristic Curve ◽  
Simulated Data ◽  
Catalytic Reactions ◽  
Multiphase Model ◽  
Simulation Results ◽  
Eulerian Multiphase Model ◽  
Good Agreement

This work has as objective the study experimental and computational of the hydrodynamics of gas-solid fluidized bed. The gas-solid fluidized beds present important applications in chemical industry; among typical examples of fluidized beds some applications could be outlined: the syntheses and catalytic reactions, the catalytic regeneration, the combustion and gasification of coal, coating, drying, etc. The simulated data were obtained through the commercial CFD (Computational fluid dynamics), and the results were compared to those obtained by experiments conducted in a fluidized bed, containing jambu seeds (Sphilantes oleracea L.) of 772.21  2.98 μm in diameter, sphericity de 0.45  0.0066, bulk density 1130.8 ± 0.22 Kg/m3 and with porosity 0.2303  0.0099. In this work the porosity profile and characteristic curve of fluidized bed were calculated by using an Eulerian multiphase model. The comparisons showed a very good agreement between experimental and simulation results.

Upward Vertical Two-Phase Flow Through an Annulus—Part II: Modeling Bubble, Slug, and Annular Flow

1992 ◽  
Vol 114 (1) ◽  
pp. 14-30 ◽  
Author(s):  
E. F. Caetano ◽  
O. Shoham ◽  
J. P. Brill
Keyword(s):  
Flow Pattern ◽  
Annular Flow ◽  
Two Phase Flow ◽  
Flow Behavior ◽  
Bubble Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Through ◽  
Physical Phenomena ◽  
Good Agreement

Mechanistic models have been developed for each of the existing two-phase flow patterns in an annulus, namely bubble flow, dispersed bubble flow, slug flow, and annular flow. These models are based on two-phase flow physical phenomena and incorporate annulus characteristics such as casing and tubing diameters and degree of eccentricity. The models also apply the new predictive means for friction factor and Taylor bubble rise velocity presented in Part I. Given a set of flow conditions, the existing flow pattern in the system can be predicted. The developed models are applied next for predicting the flow behavior, including the average volumetric liquid holdup and the average total pressure gradient for the existing flow pattern. In general, good agreement was observed between the experimental data and model predictions.

A Novel Turbulent Aggregation Device for Flue Gas

2014 ◽  
Vol 955-959 ◽  
pp. 2425-2429 ◽  
Author(s):  
Yun Fei Li ◽  
Jian Guo Yang ◽  
Yan Yan Wang ◽  
Xiao Guo Wang
Keyword(s):  
Size Distribution ◽  
Flue Gas ◽  
Large Scale ◽  
Balance Model ◽  
Small Scale ◽  
Multiphase Model ◽  
Specific Performance ◽  
Particles Size Distribution ◽  
Scale Turbulence ◽  
Eulerian Multiphase Model

The purpose of this study is to construct a turbulent aggregation device which has specific performance for fine particle aggregation in flue gas. The device consists of two cylindrical pipes and an array of vanes. The pipes extending fully and normal to the gas stream induce large scale turbulence in the form of vortices, while the vanes downstream a certain distance from the pipes induce small one. The process of turbulent aggregation was numerically simulated by coupling the Eulerian multiphase model and population balance model together with a proposed aggregation kernel function taking the size and inertia of particles into account, and based on data of particles’ size distribution measured from the flue of one power plant. The results show that the large scale turbulence generated by pipes favours the aggregation of smaller particles (smaller than 1μm) notably, while the small scale turbulence benefits the aggregation of bigger particles (larger than 1μm) notably and enhances the uniformity of particle size distribution among different particle groups.

scholarly journals Experimental and computational evaluation of a gas-solid suspension density distribution under circulating fluidized bed conditions

2021 ◽  
Vol 2130 (1) ◽  
pp. 012025
Author(s):  
P Mirek
Keyword(s):  
Density Distribution ◽  
Combustion Chamber ◽  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Multiphase Model ◽  
Thermal Loads ◽  
Bottom Part ◽  
Boiler Load ◽  
Suspension Density ◽  
Eulerian Multiphase Model

Abstract The paper presents the results of operational measurements of the suspension density distribution in the 966 MWth supercritical Circulating Fluidized Bed boiler. The tests were carried out for four different unit thermal loads, i.e. 40, 60, 80, and 100% MCR. The conducted operational measurements showed that the suspension density distribution of the particulate material in the combustion chamber of the CFB boiler has the form of an exponential curve with maximum values occurring in the bottom part of the furnace. On the basis of the operational data, an attempt was made to reflect the suspension density distribution in the combustion chamber of the boiler using the ANSYS CFD software. The calculations were carried out using the Eulerian multiphase model in an unsteady state condition. As revealed by the simulations, the Eulerian multiphase model allows for a quantitative representation of the suspension density distribution of the granular material only for the maximum boiler load. For other thermal loads, quantitative representation of experimental distributions of suspension density using the Eulerian method is possible except for the dense region.

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