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Title: Statistics of velocity fluctuations of Geldart A particles in a circulating fluidized bed riser

Abstract

Here, the statistics of fluctuating velocity components are studied in the riser of a closed-loop circulating fluidized bed with fluid catalytic cracking catalyst particles. Our analysis shows distinct similarities as well as deviations compared to existing theories and bench-scale experiments. The study confirms anisotropic and non-Maxwellian distribution of fluctuating velocity components. The velocity distribution functions (VDFs) corresponding to transverse fluctuations exhibit symmetry, and follow a stretched-exponential behavior up to three standard deviations. The form of the transverse VDF is largely determined by interparticle interactions. The tails become more overpopulated with an increase in particle loading. The observed deviations from the Gaussian distribution are represented using the leading order term in the Sonine expansion, which is commonly used to approximate the VDFs in kinetic theory for granular flows. The vertical fluctuating VDFs are asymmetric and the skewness shifts as the wall is approached. In comparison to transverse fluctuations, the vertical VDF is determined by the local hydrodynamics. This is an observation of particle velocity fluctuations in a large-scale system and their quantitative comparison with the Maxwell-Boltzmann statistics.

Authors:
 [1];  [2];  [3]
  1. National Energy Technology Lab. (NETL), Morgantown, WV (United States); Oak Ridge Inst. for Science and Education (ORISE), Oak Ridge, TN (United States)
  2. National Energy Technology Lab. (NETL), Morgantown, WV (United States)
  3. National Energy Technology Lab. (NETL), Morgantown, WV (United States); West Virginia Univ., Morgantown, WV (United States). Research Corp.
Publication Date:
Research Org.:
National Energy Technology Laboratory (NETL), Pittsburgh, PA, Morgantown, WV (United States); Oak Ridge Inst. for Science and Education (ORISE), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Fossil Energy (FE)
OSTI Identifier:
1440341
Report Number(s):
NETL-PUB-21279
Journal ID: ISSN 2469-990X; TRN: US1900717
Resource Type:
Accepted Manuscript
Journal Name:
Physical Review Fluids
Additional Journal Information:
Journal Volume: 2; Journal Issue: 11; Journal ID: ISSN 2469-990X
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
97 MATHEMATICS AND COMPUTING; 42 ENGINEERING; fluid-particle interactions; fluidized beds; interparticle interactions; particle-laden flows

Citation Formats

Vaidheeswaran, Avinash, Shaffer, Franklin, and Gopalan, Balaji. Statistics of velocity fluctuations of Geldart A particles in a circulating fluidized bed riser. United States: N. p., 2017. Web. doi:10.1103/PhysRevFluids.2.112301.
Vaidheeswaran, Avinash, Shaffer, Franklin, & Gopalan, Balaji. Statistics of velocity fluctuations of Geldart A particles in a circulating fluidized bed riser. United States. doi:10.1103/PhysRevFluids.2.112301.
Vaidheeswaran, Avinash, Shaffer, Franklin, and Gopalan, Balaji. Tue . "Statistics of velocity fluctuations of Geldart A particles in a circulating fluidized bed riser". United States. doi:10.1103/PhysRevFluids.2.112301. https://www.osti.gov/servlets/purl/1440341.
@article{osti_1440341,
title = {Statistics of velocity fluctuations of Geldart A particles in a circulating fluidized bed riser},
author = {Vaidheeswaran, Avinash and Shaffer, Franklin and Gopalan, Balaji},
abstractNote = {Here, the statistics of fluctuating velocity components are studied in the riser of a closed-loop circulating fluidized bed with fluid catalytic cracking catalyst particles. Our analysis shows distinct similarities as well as deviations compared to existing theories and bench-scale experiments. The study confirms anisotropic and non-Maxwellian distribution of fluctuating velocity components. The velocity distribution functions (VDFs) corresponding to transverse fluctuations exhibit symmetry, and follow a stretched-exponential behavior up to three standard deviations. The form of the transverse VDF is largely determined by interparticle interactions. The tails become more overpopulated with an increase in particle loading. The observed deviations from the Gaussian distribution are represented using the leading order term in the Sonine expansion, which is commonly used to approximate the VDFs in kinetic theory for granular flows. The vertical fluctuating VDFs are asymmetric and the skewness shifts as the wall is approached. In comparison to transverse fluctuations, the vertical VDF is determined by the local hydrodynamics. This is an observation of particle velocity fluctuations in a large-scale system and their quantitative comparison with the Maxwell-Boltzmann statistics.},
doi = {10.1103/PhysRevFluids.2.112301},
journal = {Physical Review Fluids},
number = 11,
volume = 2,
place = {United States},
year = {2017},
month = {11}
}

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Figures / Tables:

FIG. 1 FIG. 1: Fluctuating horizontal VDF measured from the experiments (symbols) at different radial locations for PSRI1 (top) and PSRI2 (bottom). Solid line represents the stretched Gaussian distribution P(cx) ∼ e−1.5|cx| 1.3

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    Figures/Tables have been extracted from DOE-funded journal article accepted manuscripts.