Particle velocity measurements in transition section of turbulent fluidized beds using optical fiber probe and CFD simulation

TY - JOUR

T1 - Particle velocity measurements in transition section of turbulent fluidized beds using optical fiber probe and CFD simulation

AU - Wu, Cheng

AU - Gao, Yong Xiang

AU - Gao, Xi

AU - Cheng, You Wei

AU - Wang, Li Jun

AU - Li, Xi

N1 - Publisher Copyright: ©, 2015, Zhejiang University. All right reserved.

PY - 2015/2/1

Y1 - 2015/2/1

N2 - Measurement of particle velocity in fluidized beds is always technically difficult. A new method based on cross-correlation principle was proposed to calculate time-averaged velocity of particles. Considering the different reliabilities of signal segments, a cross-correlation coefficient was introduced into the formula for calculating time-averaged velocity. A PV6D optical fiber probe was used to obtain original signals in a fluidized bed with 200 mm i.d., and the time-averaged velocities calculated from three different methods were compared. The calculated particle volume flow rates based on different velocity calculating methods indicate that the method proposed in this paper is more reliable. Based on this method, particle time-averaged velocity was measured at different heights in the transition section of a turbulent fluidized bed. A modified three-zone drag law model was used to predict the flow structure of particles with clustering behavior. The experimental and simulation results both indicate that, from the transition section to the dilute section, particle velocity of the core region rises at first and then declines, the radial velocity distribution changes from a steep curve to a flat one, and then becomes steep again. This result depends on both solid concentration distribution and gas velocity distribution.

AB - Measurement of particle velocity in fluidized beds is always technically difficult. A new method based on cross-correlation principle was proposed to calculate time-averaged velocity of particles. Considering the different reliabilities of signal segments, a cross-correlation coefficient was introduced into the formula for calculating time-averaged velocity. A PV6D optical fiber probe was used to obtain original signals in a fluidized bed with 200 mm i.d., and the time-averaged velocities calculated from three different methods were compared. The calculated particle volume flow rates based on different velocity calculating methods indicate that the method proposed in this paper is more reliable. Based on this method, particle time-averaged velocity was measured at different heights in the transition section of a turbulent fluidized bed. A modified three-zone drag law model was used to predict the flow structure of particles with clustering behavior. The experimental and simulation results both indicate that, from the transition section to the dilute section, particle velocity of the core region rises at first and then declines, the radial velocity distribution changes from a steep curve to a flat one, and then becomes steep again. This result depends on both solid concentration distribution and gas velocity distribution.

KW - Computational fluid dynamics (CFD)

KW - Fluidized bed

KW - Optical fiber probe

KW - Particle velocity

UR - http://www.scopus.com/inward/record.url?scp=84925585159&partnerID=8YFLogxK

U2 - 10.3969/j.issn.1003-9015.2015.01.002

DO - 10.3969/j.issn.1003-9015.2015.01.002

M3 - 文章

AN - SCOPUS:84925585159

SN - 1003-9015

VL - 29

SP - 11

EP - 19

JO - Gao Xiao Hua Xue Gong Cheng Xue Bao/Journal of Chemical Engineering of Chinese Universities

JF - Gao Xiao Hua Xue Gong Cheng Xue Bao/Journal of Chemical Engineering of Chinese Universities

IS - 1

ER -