Simulation of Gas-Solid Flow Characteristics in Three-Dimensional Rotational Spouted-Fluidized Bed

2014 ◽  
Vol 496-500 ◽  
pp. 913-917
Author(s):  
Xin Feng Long ◽  
Yi Liu ◽  
Bo Lou
Keyword(s):  
Fluidized Bed ◽  
Gas Flow ◽  
Solid Phase ◽  
Velocity Ratio ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Cylinder Wall ◽  
Flow State ◽  
Solid Flow ◽  
Tangential Wind

In order to study the gas-solid flow characteristics in a rotational spouted-fluidized bed dryer, the eulerian multi-phase model was applied in three-dimensional numerical simulation of a rotational spouted-fluidized bed to analyze the effect of different velocity ratios between bottom and tangential wind on gas and particle velocity distribution characteristics, and the change rule of gas-solid flow state with the time at the velocity ratio of 30 m·s-1/30 m·s-1 was derived. The results show that the increase of tangential wind velocity is propitious to enhance the gas flow rate in the region near the wall and make the gas-solid phase mix sufficiently as well as augment of the contact area of gas and particle phase, and decrease of the gas flow dead zones and the adhesion of viscous materials to cylinder wall. However, the negative pressure formed by the entrainment effect of tangential wind goes against the development of gas flow along the axial direction reducing the penetration effect of axial wind to the granular layer.

Three-dimensional computational fluid dynamics investigation of hydrodynamics behaviour of gas–solid flow in fluidized bed of Geldart D particles

2021 ◽  
pp. 095440892098769
Author(s):  
Fazia Aiche ◽  
Salah Belaadi ◽  
Adel Lalaoua ◽  
Abdallah Sofiane Berrouk ◽  
Abdelwahid Azzi
Keyword(s):  
Fluidized Bed ◽  
Gas Flow ◽  
Turbulence Modeling ◽  
Volume Fraction ◽  
Solid Phase ◽  
Fluid Model ◽  
Flow Behavior ◽  
Three Dimensional ◽  
Industrial Processes ◽  
Cyclic Process

Fluidized beds are widely used in many industrial processes as they ensure the desirable high-intensity heat and mass transfers between gas and particles and offer the possibility to perform operations in a continuous mode and powders recycling. Some of these industrial processes use Geldart D type of powders and operate in the slugging mode. This paper presents a 3 D numerical model of gas-solid flows in a fluidized bed based on the Two-Fluid Model (TFM). Turbulence modeling (k- ε) was used to predict flow behavior in fluidized bed of Geldart D particles. The solid phase consists of Geldart D powders and the gas flow is in a slug regime. The numerical results are validated against the experimental work of Azzi et al. Model predictions on flow patterns, bed expansion, volume fraction time series and pressure drop fluctuations are presented and discussed in details in order to demonstrate the cyclic process of slug formation (onset, growth, rising and bursting of slugs) and its effects on the overall performance of beds fluidizing Geldart D type of powders.

3D Numerical Simulation of Polydisperse Pressurized Gas-Solid Fluidized Bed

2011 ◽  
Author(s):  
P. Fede ◽  
O. Simonin ◽  
I. Ghouila
Keyword(s):  
Numerical Simulation ◽  
Fluidized Bed ◽  
Ethylene Polymerization ◽  
Solid Phase ◽  
Three Dimensional ◽  
Gas Velocity ◽  
Particle Segregation ◽  
3D Numerical Simulation ◽  
Model Predictions ◽  
The Mean

Three dimensional unsteady numerical simulations of dense pressurized polydisperse fluidized bed have been carried out. The geometry is a medium-scale industrial pilot for ethylene polymerization. The numerical simulation have been performed with a polydisperse collision model. The consistency of the polydisperse model predictions with the monodisperse ones is shown. The results show that the pressure distribution and the mean vertical gas velocity are not modified by polydispersion of the solid phase. In contrast, the solid particle species are not identically distributed in the fluidized bed indicating the presence of particle segregation.

Effect of elevated pressure on gas-solid flow characteristics in a circulating fluidized bed

2020 ◽  
Vol 366 ◽  
pp. 470-476 ◽  
Author(s):  
Daoyin Liu ◽  
Jinding Hu ◽  
Jialong Song ◽  
Cai Liang ◽  
Chuanlong Xu ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Flow Characteristics ◽  
Elevated Pressure ◽  
Solid Flow

Influence of CGD structure on burden descending behavior in COREX shaft furnace

2019 ◽  
Vol 116 (3) ◽  
pp. 304 ◽  
Author(s):  
Xingsheng Zhang ◽  
Zongshu Zou ◽  
Zhiguo Luo
Keyword(s):  
Large Scale ◽  
Gas Flow ◽  
Shaft Furnace ◽  
Three Dimensional ◽  
Interaction Force ◽  
Flow Patterns ◽  
Solid Flow ◽  
Reducing Gas ◽  
A New Technique ◽  
Actual Size

For improving the reducing gas flow in the center of a large-scale shaft furnace, the central gas distribution (CGD) device, a new technique, is proposed and installed in the shaft furnace. Because of its less-developed history, the solid flow in the shaft furnace with CGD is unclear. In this work, a three-dimensional cylindrical model of COREX-3000 shaft furnace in actual size is established based on DEM. Four types of burden, including pellet, lump ore, coke and flux, are taken into consideration in the model. The model is validated by experiment and then it is used to investigate the influence of CGD structure on solid flow patterns, burden descending velocity, interaction force and abrasive wear. The results show that the CGD structure has some effects on the solid flow patterns and burden descending velocity. As the CGD diameter increases, the interaction force between particles is decreased but the total abrasion energy on CGD is increased. As the CGD height increases, both the interaction force between particles and the total abrasion energy on CGD are decreased.

Experimental and Numerical Study of Cold Gas-Solid Flow Regimes in a Fluidized Bed Gasifier

2017 ◽  
Author(s):  
Anton Pylypenko ◽  
Yevgenii Rastigejev ◽  
Lijun Wang ◽  
Abolghasem Shahbazi
Keyword(s):  
Fluidized Bed ◽  
Numerical Study ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Silica Sand ◽  
State University ◽  
Solid Flow ◽  
Fluidized Bed Gasifier ◽  
Isothermal Gas ◽  
Cold Gas

The objective of this work is to analyze the dynamics and regimes of cold gas-solid flow in a biomass gasifier that is built at North Carolina Agricultural and Technical State University and to identify its corresponding ranges of operating conditions. The value of the minimum fluidization velocity Umf ≈ 8 cm/s has been found experimentally in a series of measurements of a pressure drop in the fluidized bed filled with Gledart type-B silica sand for the range of superficial gas velocities between 0 and 40 cm/s. To complement the experimental results, a set of three-dimensional numerical simulations of the isothermal gas-solid flow based on Eulerian-Eulerian approach has been performed. The analysis of the fluidization characteristics such as axial void fraction distributions has allowed us to evaluate the dependence of the bed expansion ratios from the flow superficial velocity. Good agreement between experimental and numerical results for the considered operating conditions of the gasifier has been observed.

Validation and Application of Computational Modeling to Reduce Erosion in a Circulating Fluidized Bed Boiler

2012 ◽  
Vol 10 (1) ◽  
Author(s):  
Peter J. Blaser ◽  
Giorgio Corina
Keyword(s):  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Complex Geometry ◽  
Three Dimensional ◽  
Palm Kernel ◽  
Operational Experience ◽  
Solid Flow ◽  
Internal Surfaces ◽  
And Performance ◽  
Palm Kernel Shells

Abstract The 40 MW Strongoli power plant, located in the Calabria region of Italy, produces power from 100% biomass sources. The combustion of wood biomass, exhausted olive residues and palm kernel shells, occurs in a sand-filled, Circulating Fluidized Bed (CFB) combustor. Operational experience with the unit dates back to 2003. This paper describes the optimization of the boiler in order to minimize erosion on internal surfaces and structures. Detailed three-dimensional, transient, multiphase gas-solid flow fields were computed and are presented. Details of the complex geometry include the combustion chamber, cyclone, cyclone dipleg, seal pot, fluidized bed heat exchanger and cyclone outlet structures including suspension tubes. The gas-solid flow was computed using the commercially-available software package Barracuda, a CFD software based on a unique Eulerian-Lagrangian formulation that was essential to the success of the subject work. Both instantaneous and time-averaged results were obtained. Results were validated against operational erosion experience. The validated model, in turn, was utilized to redesign various components of the boiler, optimizing both erosion characteristics and performance behaviour of the system. The redesigned unit was commissioned in early 2012.

scholarly journals Flow Characteristics of a 35° Inclined Turbulent Jet in a Crossflow on a Concave Surface

1992 ◽  
Author(s):  
Sang Woo Lee ◽  
Joon Sik Lee ◽  
Taik Sik Lee
Keyword(s):  
Near Field ◽  
Velocity Ratio ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Horseshoe Vortex ◽  
Concave Surface ◽  
Velocity Measurements ◽  
Downstream Region ◽  
Type Flow ◽  
Streamwise Pressure Gradient

The effect of the concave curvature on the flow of a streamwise 35° inclined jet issuing into a crossflow boundary layer has been investigated experimentally. Three-dimensional velocity measurements are performed in the near-field and some downstream region of jet exit by using a 5-hole directional probe. Since the main purpose is to investigate solely the effect of the concave curvature, the upper wall of the curved region is adjusted to minimize the effect of the streamwise pressure gradient. The results show that in the vicinity of the jet exit, the bound vortex dominates the flow structure, while in the far downstream region, the concave curvature plays an important role in converting the secondary flow into the Taylor-Görtler type flow. In addition, vortices rotating in the opposite direction with respect to the bound vortex is generated at both sides of the bound vortices, which stimulate the mixing of the jet and crossflow fluid. When the velocity ratio is large, the horseshoe vortex exists in the neighborhood of the jet exit, even though the strength is very weak compared with the bound vortex, however this horseshoe vortex may act as a kind of steady disturbance on the concave surface.

The Simulation and Optimization on Flow Field in Intake Port of Engine Based on RE and CFD

2014 ◽  
Vol 1079-1080 ◽  
pp. 926-929
Author(s):  
Dan Han ◽  
Qian Wang ◽  
Bing Huan Li ◽  
Guo Jun Zhang ◽  
Shuo Wang
Keyword(s):  
Flow Field ◽  
Laser Scanning ◽  
Gas Flow ◽  
Gasoline Engine ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Turbulence Models ◽  
Intake Port ◽  
Three Dimensional Model ◽  
Simulation And Optimization

Intake port is an important part of the gasoline engine, its structure will influence the gas flow characteristics which directly affects the performance of the engine [1]. In this paper, three-dimensional CFD calculation and structural optimization were used to research the performance of gasoline engine. Firstly, the method of laser scanning and UG software were used to reverse modeling engine exhaust port and get the three-dimensional model. Secondly, after setting boundary conditions and turbulence models, the air flowing through the intake ports were simulated by FLUENT software respectively. Finally, based on numerical methods, the pressure field, velocity field were shown. The results of the simulation of flow field characteristics analysis show that the simulation and experimental results are in good agreement.

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