Particle velocity profiles and solid flow patterns in spouted beds

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.

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Particle Velocity Profiles in Underwater Horns

The Journal of the Acoustical Society of America ◽

10.1121/1.1976126 ◽

1971 ◽

Vol 49 (1A) ◽

pp. 90-91

Author(s):

T. D. Mathis ◽

R. D. Finch

Keyword(s):

Particle Velocity ◽

Velocity Profiles

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Downstream relaxation of velocity profiles in pipe-flow with swirl disturbances

tm - Technisches Messen ◽

10.1515/teme-2016-0029 ◽

2016 ◽

Vol 83 (12) ◽

Cited By ~ 4

Author(s):

Simon Graner ◽

Denis F. Hinz ◽

Christian Breitsamter

Keyword(s):

Cross Sections ◽

Pipe Flow ◽

Performance Indicators ◽

Laser Doppler Velocimetry ◽

Swirling Flow ◽

Flow Patterns ◽

Velocity Profiles ◽

Doppler Velocimetry ◽

Characteristic Shape ◽

And Performance

AbstractWe study characteristic flow patterns downstream of a standardized swirl disturbance generator using laser-Doppler velocimetry (LDV). To investigate the spatial development of flow patterns, we conduct LDV measurements in cross-sections located at various distances downstream from the swirl disturbance generator. Focusing on velocity profiles, decay of swirl, and performance indicators used to describe the characteristic shape of the velocity profiles, we systematically compare the experimental results with available references and various theories for decay of swirl disturbances. We find that the standardized swirl disturbance generator provides exponentially decaying swirling flow that is best captured by the theory of Steenbergen and Voskamp

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Effects of Riser Diameter on Solids Holdup and Particle Velocity Profiles in Circulating Fluidized Bed Riser Systems

Journal of Energy Resources Technology ◽

10.1115/1.4046139 ◽

2020 ◽

Vol 142 (7) ◽

Author(s):

Ronald W. Breault ◽

Steven L. Rowan ◽

Justin M. Weber ◽

Jingsi Yang

Keyword(s):

Fluidized Bed ◽

Particle Velocity ◽

Circulating Fluidized Bed ◽

Velocity Profiles ◽

Small Scale ◽

Sauter Mean Diameter ◽

Particle Size Range ◽

Cold Flow ◽

Solids Holdup ◽

Radial Profiles

Abstract Tests were performed in a 0.1-m diameter small circulating fluidized bed (SCFB) and 0.3 m diameter cold flow circulating fluidized bed (CFCFB) riser systems located at the National Energy Technology Laboratory (NETL) to study the effects of riser diameter on the riser hydrodynamics. These tests were performed at solids circulation rates of Gs = 20 and 75 kg/m2 s and superficial gas velocities of Ug = 5.8 and 6.5 m/s using high-density polyethylene (HDPE) pellets with a density of 0.863 g/cm3, particle size range of 600–1400 µm (with a Sauter mean diameter of 871 µm, placing them in the Geldart B classification). Comparisons of riser axial pressure and solids fraction profiles, radial particle velocity profiles, and radial profiles of higher statistical moments and select chaos analysis parameters were considered. The results showed that for a given Ug and Gs, the smaller diameter riser exhibited characteristics associated with more dilute solids flow than that observed in the larger diameter riser. Additionally, the larger diameter riser exhibited a downward flow of solids near the wall under all test conditions, whereas the smaller diameter riser data exhibited little or no indications of solids downflow near the wall. These findings suggest that, from an industrial standpoint, a direct scaleup of small-scale tests cannot readily be accomplished as the solids holdup and the solids velocity profiles in small units (those normally tested in the laboratory) are not similar to those of large units and the performance of large units can therefore not be predicted from small-scale tests.

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Numerical and Experimental Study of Multiphase Transient Core-Annular Flow Patterns in a Spouted Bed

Journal of Energy Resources Technology ◽

10.1115/1.4047305 ◽

2020 ◽

Vol 142 (9) ◽

Cited By ~ 8

Author(s):

Ling Zhou ◽

Chen Han ◽

Ling Bai ◽

Weidong Shi ◽

Ramesh Agarwal

Keyword(s):

Numerical Simulations ◽

Flow Pattern ◽

High Speed ◽

Annular Flow ◽

Fluid Phase ◽

Flow Patterns ◽

Spouted Bed ◽

High Speed Imaging ◽

Spouted Beds ◽

Number Of Particles

Abstract Dense solid–gas bubbling systems with combined fluid-particle motion are among one of the most extensively used fluidization forms used in the chemical industry. Therefore, it is important to have a good understanding of the hydrodynamic behavior of bubbles. In this paper, both the experiment and numerical simulations are used to investigate the flow patterns in a spouted bed. For numerical simulations, the bidirectional coupling simulations using computational fluid dynamics (CFD) with discrete element method (DEM) are conducted. The results show that the simulations can accurately predict the bubbles morphology compared with the experimental results. When the number of particles is 30,000, only a single core-annular flow pattern appears. When the number of particles is increased to 36,500, the single bubble in the spouted bed transitions into two and a double core-annular flow pattern emerges. As the number of particles is increased to 43,000, a complex multicore-annular flow pattern appears. These flow patterns are also observed in the experiments using high-speed imaging camera. This paper analyzes and explains the causes of these flow phenomena from the dynamic characteristics of particle phase and fluid phase. These results have great significance in providing guidance for optimization of dense phase bubbling spouted beds.

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Effect of swirling gas nozzles on gas-solid flow patterns inside a novel multi-regime riser

Powder Technology ◽

10.1016/j.powtec.2020.03.048 ◽

2020 ◽

Vol 367 ◽

pp. 233-242

Author(s):

Shengsheng Wang ◽

Ming Cheng ◽

Xiaolin Zhu ◽

Cunhao Lin ◽

Guowei Wang ◽

...

Keyword(s):

Flow Patterns ◽

Solid Flow

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