TY - JOUR
T1 - Image analysis measurements of particle coefficient of restitution for coal gasification applications
AU - Gibson, La Tosha M.
AU - Gopalan, Balaji
AU - Pisupati, Sarma V.
AU - Shadle, Lawrence J.
N1 - Funding Information:
The authors would like to acknowledge Jim Spenik for the construction of the apparatus for the particle wall experiments using the eductor and the calibration of the apparatus using the Fiber Optic System, Chris Ludlow for the design and construction of the particle target, and Paul Yue for the construction of the apparatus for the drop experiments and calibration using Laser Doppler Velocimetry. Funding for this work was provided by the Advanced Gasification Program from the Office of Fossil Energy of the Department of Energy .
PY - 2013/10
Y1 - 2013/10
N2 - New robust Lagrangian computational fluid dynamic (CFD) models are powerful tools that can be used to study the behavior of a diverse population of coal particle sizes, densities, and mineral compositions in entrained gasifiers. By using this approach, the responses of the particles impacting the wall were characterized over a range of velocities (1 to 8. m/s) and incident angles (90 to 20°). Within CFD models, the kinematic coefficient of restitution is the boundary condition defining the particle wall behavior. Four surfaces were studied to simulate the physical conditions of different entrained-flow gasification particle-surface collision scenarios: 1) a flat metal plate 2) a low viscosity silicon adhesive, 3) a high viscosity silicon adhesive, and 4) adhered particles on a flat metal plate with Young's modulus of elasticity ranging from 0.9 to 190. GPa. Entrained flow and drop experiments were conducted with granular coke particles, polyethylene beads and polystyrene pellets. The particle normal and tangential coefficients of restitution were measured using high speed imaging and particle tracking. The measured coefficients of restitution were observed to have a strong dependence on the rebound angles for most of the data. Suitable algebraic expressions for the normal and the tangential component of the coefficient of restitution were developed based upon ANOVA analysis. These expressions quantify the effect of normalized Young's modulus, particle equancy, and relative velocity on the coefficient of restitution. The coefficient of restitution did not have a strong dependence on the particle velocity over the range considered as long as the velocity was above the critical velocity. However, strong correlations were found between the degree of equancy of the particles and the mean coefficient of restitution such that the coefficient of restitution decreased for smaller particle equancies. It was concluded that the degree of equancy and the normalized Young's modulus should be considered in applications such as gasification and other cases involving the impact of non-spherical particles and complex surfaces. Sliding was observed when particles impacted on oblique surfaces; however, the resulting effects were within the range of measurement uncertainties.
AB - New robust Lagrangian computational fluid dynamic (CFD) models are powerful tools that can be used to study the behavior of a diverse population of coal particle sizes, densities, and mineral compositions in entrained gasifiers. By using this approach, the responses of the particles impacting the wall were characterized over a range of velocities (1 to 8. m/s) and incident angles (90 to 20°). Within CFD models, the kinematic coefficient of restitution is the boundary condition defining the particle wall behavior. Four surfaces were studied to simulate the physical conditions of different entrained-flow gasification particle-surface collision scenarios: 1) a flat metal plate 2) a low viscosity silicon adhesive, 3) a high viscosity silicon adhesive, and 4) adhered particles on a flat metal plate with Young's modulus of elasticity ranging from 0.9 to 190. GPa. Entrained flow and drop experiments were conducted with granular coke particles, polyethylene beads and polystyrene pellets. The particle normal and tangential coefficients of restitution were measured using high speed imaging and particle tracking. The measured coefficients of restitution were observed to have a strong dependence on the rebound angles for most of the data. Suitable algebraic expressions for the normal and the tangential component of the coefficient of restitution were developed based upon ANOVA analysis. These expressions quantify the effect of normalized Young's modulus, particle equancy, and relative velocity on the coefficient of restitution. The coefficient of restitution did not have a strong dependence on the particle velocity over the range considered as long as the velocity was above the critical velocity. However, strong correlations were found between the degree of equancy of the particles and the mean coefficient of restitution such that the coefficient of restitution decreased for smaller particle equancies. It was concluded that the degree of equancy and the normalized Young's modulus should be considered in applications such as gasification and other cases involving the impact of non-spherical particles and complex surfaces. Sliding was observed when particles impacted on oblique surfaces; however, the resulting effects were within the range of measurement uncertainties.
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U2 - 10.1016/j.powtec.2013.06.001
DO - 10.1016/j.powtec.2013.06.001
M3 - Article
AN - SCOPUS:84880974403
SN - 0032-5910
VL - 247
SP - 30
EP - 43
JO - Powder Technology
JF - Powder Technology
ER -