Abstract
The effect of wall roughness on particle dynamics in gas-particle flows has been studied both experimentally and numerically, but mainly for channel, pipe, and boundary-layer flows. The present authors did numerical studies and detailed phase-Doppler particle anemometry (PDPA) measurements on the effect of wall roughness for particle dynamics in separating (sudden-expansion and swirling) gas-particle flows, as well as channel flows. The simulated gas-particle flow showed that the prediction results accounting for the wall roughness agree well with the measurement results. The PDPA measurements of backward-facing step gas-particle flows showed that as the wall roughness increases, the longitudinal and the transverse time-averaged particle velocities decrease, but the longitudinal and transverse particle fluctuation velocities i ncrease.
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Abbreviations
- bc:
-
boundary condition
- D :
-
diffusion term
- e :
-
restitution coefficient
- f :
-
friction coefficient; probability density distribution function
- G :
-
phase interaction term
- n :
-
number density
- P :
-
pressure term
- r, x, y, z :
-
coordinates
- R :
-
relation; radius of swirl chamber
- t :
-
time
- u,v :
-
velocity
- α :
-
virtual wall inclination; volume fraction
- α′ :
-
maximum value of virtual wall inclination
- ε :
-
dissipation term
- ρ :
-
density
- ∏:
-
pressure-strain term
- 1, 2:
-
before and after collision
- g:
-
gas phase
- i:
-
inner field
- i, j, k :
-
components in x, y, z directions
- in:
-
inlet value
- m:
-
material density
- p:
-
particle phase
- s:
-
solid phase
- w:
-
wall value
- —:
-
Reynolds time-averaged value
- =:
-
mass-weighed averaged stress
- ~:
-
mass-weighed averaged velocity
- ’:
-
fluctuation value in Reynolds time-averagin
- “:
-
fluctuation value in mass-weighed averaging
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Acknowledgements
This study was sponsored by the Special Funds for the Major State Basic Research, China (Grant No. G-1999-0222-08) and the National Natural Science Foundation of China (Grant Nos. 51390493 and 51266008).
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Zhou, L., Zhang, X. & Yu, Y. Experimental and numerical studies on the wall-roughness effect to particle dynamics in various gas-particle flows. Exp. Comput. Multiph. Flow (2024). https://doi.org/10.1007/s42757-023-0168-8
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DOI: https://doi.org/10.1007/s42757-023-0168-8