TY - JOUR

T1 - Numerical investigation of effects of particle shape on dispersion in an isotropic turbulent flow

AU - Zhang, Wei

AU - Watanabe, Hiroaki

AU - Kitagawa, Toshiaki

N1 - Funding Information:
This study is supported by JSPS KAKENHI Grant No. 25420173 and 16K06125 .
Publisher Copyright:
© 2018 The Society of Powder Technology Japan

PY - 2018/9

Y1 - 2018/9

N2 - To investigate the effects of particle shape on the dispersion in an isotropic turbulent flow, herein two direct numerical simulations are performed. The six degrees of freedom motion of spherical and spheroidal particles in a vertical uniform flow and a gas-particle two-way isotropic turbulent flow. The former, which is investigated using a numerical simulation with the Arbitrary Lagrangian-Euler (ALE) method, shows that a spheroidal particle travels with rotating and oscillating motions, which significantly affect the pressure and the friction force on the particle's surface. The trend of the fluid force acting on the spheroidal particle's surface also oscillates and differs from that on a spherical particle. The time variation of the fluid force on the spheroidal particle is modeled in the CD equation, which has a sine curve's PDF relation with Rep and the particle's maximum and minimum CD values. The latter simulation examines the effects of the particle shape on the dispersion with the motion model developed above. The particle's dispersion behavior, which is analyzed by the statistical variable D and the Radial Distribution Function (RDF), shows that the dispersion motion is markedly affected by particle's sphericity, especially for particles with a relatively small sphericity. The results suggest that this difference can influence ignitability, flammability, and the concentration of combustible gases released by particles, and requires further study.

AB - To investigate the effects of particle shape on the dispersion in an isotropic turbulent flow, herein two direct numerical simulations are performed. The six degrees of freedom motion of spherical and spheroidal particles in a vertical uniform flow and a gas-particle two-way isotropic turbulent flow. The former, which is investigated using a numerical simulation with the Arbitrary Lagrangian-Euler (ALE) method, shows that a spheroidal particle travels with rotating and oscillating motions, which significantly affect the pressure and the friction force on the particle's surface. The trend of the fluid force acting on the spheroidal particle's surface also oscillates and differs from that on a spherical particle. The time variation of the fluid force on the spheroidal particle is modeled in the CD equation, which has a sine curve's PDF relation with Rep and the particle's maximum and minimum CD values. The latter simulation examines the effects of the particle shape on the dispersion with the motion model developed above. The particle's dispersion behavior, which is analyzed by the statistical variable D and the Radial Distribution Function (RDF), shows that the dispersion motion is markedly affected by particle's sphericity, especially for particles with a relatively small sphericity. The results suggest that this difference can influence ignitability, flammability, and the concentration of combustible gases released by particles, and requires further study.

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U2 - 10.1016/j.apt.2018.05.011

DO - 10.1016/j.apt.2018.05.011

M3 - Article

AN - SCOPUS:85047798981

SN - 0921-8831

VL - 29

SP - 2048

EP - 2060

JO - Advanced Powder Technology

JF - Advanced Powder Technology

IS - 9

ER -