Measuring turbulence in a circulating fluidized bed using PIV techniques

Kashyap, Mayank; Chalermsinsuwan, Benjapon; Gidaspow, Dimitri

doi:10.1016/j.partic.2011.06.007

Cited by 29 publications

(10 citation statements)

References 75 publications

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“…In practice, due to the lack of understanding of the scale dependence of heterogeneity, one can readily find different criteria have been proposed for the length scale in which a two-fluid model (TFM) applies, ranging from e.g. 25,[39][40][41][42][43] On the other hand, along the horizontal (nondriving) direction, a Gaussian distribution for a dense up-flow regime 43 and a close-to-Gaussian distribution for a core-annulus regime 42 were reported. 30 Recent experiments have shown that the probability density function (PDF) of particle velocity has apparent deviation from Gaussian distribution for vibro-fluidized systems or granular gases [31][32][33][34][35][36][37][38] and gas-fluidized systems, 25,39-43 as summarized in Table 1.…”

Section: Introductionmentioning

confidence: 99%

“…10d p 28,29 down to even less than 1d p . 30 Recent experiments have shown that the probability density function (PDF) of particle velocity has apparent deviation from Gaussian distribution for vibro-fluidized systems or granular gases [31][32][33][34][35][36][37][38] and gas-fluidized systems, 25,[39][40][41][42][43] as summarized in Table 1. In greater detail, the PDF of particle velocity shows a non-Gaussian shape in a vibro-fluidized bed, where energy was injected from vibrating boundaries and dissipated through particle collisions.…”

Section: Introductionmentioning

confidence: 99%

“…A skewed distribution and even a bimodal distribution can be found along vertical (driving) direction. 25,[39][40][41][42][43] On the other hand, along the horizontal (nondriving) direction, a Gaussian distribution for a dense up-flow regime 43 and a close-to-Gaussian distribution for a core-annulus regime 42 were reported. A skewed distribution was also found for a core-annulus regime although only small skewness was maintained.…”

Section: Introductionmentioning

confidence: 99%

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Scale‐dependent nonequilibrium features in a bubbling fluidized bed

2018

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We investigate experimentally the nonequilibrium features in a pseudo 2‐D bubbling fluidized bed. Velocities of individual particles are measured by using a particle tracking velocimetry (PTV) method, and void fractions are obtained with the Voronoi tessellation. A bimodal shape of probability density function (PDF) for particle vertical velocity is found in not only time‐averaged but also time‐varying statistics, which is caused by the transition between the dense and dilute phases and breaks the local‐equilibrium assumption in continuum modeling of fluidized beds. The results of time‐varying radial distribution function and voidage distribution also confirm this finding. Moreover, the analysis of voidage, particle velocity, granular temperature and turbulent kinetic energy of particles shows that there is no scale‐independent plateau over the interface, and it seems hard to find a scale‐independent plateau to separate the micro‐ and meso‐scales of fluidized beds, which require sub‐grid meso‐scale modeling for continuum or coarse‐graining methods of gas‐fluidized systems. © 2018 American Institute of Chemical Engineers AIChE J, 64: 2364–2378, 2018

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Scale‐dependent nonequilibrium features in a bubbling fluidized bed

2018

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“…The granular temperature has also been investigated using the TFM model (Loha, Chattopadhyay, & Chatterjee, 2013), the collisional exchange model (Zhao, O'Rourke, & Snider, 2009), and through experiments (Kashyap, Chalermsinsuwan, & Gidaspow, 2011). Though there is much progress in studying particle dynamic characteristics, studies on particle rotational characteristics are still lacking.…”

Section: Introductionmentioning

confidence: 99%

Rotation characteristic and granular temperature analysis in a bubbling fluidized bed of binary particles

Wang

Yan

et al. 2015

Particuology

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“…The solids slugging structure can be measured with the technology of gamma ray densitometry [30,31]. Other techniques such as particle image velocimetry (PIV), laser doppler anemometry (LDA), and fiber optic probe can also be used for the measurement of solids structure in fluidized-bed reactors [31][32][33][34]. In this work the measurement of solids concentration was not done due to lack of these advanced measuring instruments; however, the measurement of solids concentration will be included in our future studies to improve the quality of our research.…”

Section: Cfd Simulation Resultsmentioning

confidence: 99%

Application of Scaling-Law and CFD Modeling to Hydrodynamics of Circulating Biomass Fluidized Bed Gasifier

et al. 2016

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Two modeling approaches, the scaling-law and CFD (Computational Fluid Dynamics) approaches, are presented in this paper. To save on experimental cost of the pilot plant, the scaling-law approach as a low-computational-cost method was adopted and a small scale column operating under ambient temperature and pressure was built. A series of laboratory tests and computer simulations were carried out to evaluate the hydrodynamic characteristics of a pilot fluidized-bed biomass gasifier. In the small scale column solids were fluidized. The pressure and other hydrodynamic properties were monitored for the validation of the scaling-law application. In addition to the scaling-law modeling method, the CFD approach was presented to simulate the gas-particle system in the small column. 2D CFD models were developed to simulate the hydrodynamic regime. The simulation results were validated with the experimental data from the small column. It was proved that the CFD model was able to accurately predict the hydrodynamics of the small column. The outcomes of this research present both the scaling law with the lower computational cost and the CFD modeling as a more robust method to suit various needs for the design of fluidized-bed gasifiers.

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Measuring turbulence in a circulating fluidized bed using PIV techniques

Cited by 29 publications

References 75 publications

Scale‐dependent nonequilibrium features in a bubbling fluidized bed

Scale‐dependent nonequilibrium features in a bubbling fluidized bed

Rotation characteristic and granular temperature analysis in a bubbling fluidized bed of binary particles

Application of Scaling-Law and CFD Modeling to Hydrodynamics of Circulating Biomass Fluidized Bed Gasifier

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