Abstracts - KTH Mechanics

Large Eddy Simulation of Horizontal Particle-Laden Channel
Flows with Effect of Wall Roughness
A. Konan ∗ , O. Simonin ∗ and K. D. Squires †
Detailed analysis of the particle behaviour in horizontal channel in experimental
works by Schade et al. 1 , Sommerfeld et al. 2, 3 show that the wall roughness
affects strongly the particle transport. They observed a modification of pressure loss,
particle mass flux, particle mean and fluctuating velocities along a narrow channel,
due to the roughness effect on the particle-wall interaction mechanism. Such an effect
4, 5,
has been accounted for in several numerical studies based on RANS approaches
6, 7 leading to very convincing results. In particular, according to Sommerfeld, the
roughness effect may be accounted for by assuming that any incident particle collides
with a virtual wall with a random inclination obeying a given truncated Gaussian
probability distribution function satifying the realisability of the particle bouncing
angle.
We have carried out Large-Eddy Simulation (LES) of the carrier phase flow coupled
with Discrete Particle Simulation (DPS) using the Sommerfeld’s virtual wall
model. Lagrangian particle tracking is computed by assuming only gravity and drag
forces. Simulations are performed in the dilute limit in which particle-particle collisions
are accounted for, using a deterministic approach (hard-sphere model), but
neglecting the modification of the underlying carrier flow by momentum exchange
with the particles. Computations were performed for spherical glass beads with diameters
between 130µm and 195µm and different wall roughness standard deviations
(1.2 ◦ and 7.0 ◦ ). The numerical predictions (mass flux, mean and turbulent velocities)
are compared with Sommerfeld’s experimental results 8 .
In addition, statistical properties of the incident and bouncing particle velocities
are measured from the simulations and used for the theoretical derivation of particulate
eulerian wall boundary conditions 9 .
∗ Institut de Mécanique des Fluides, Allée du Professeur Camille Soula, 31400 Toulouse, France.
† Department of Mechanical and Aerospace Engineering, Arizona State University, Tempe, Ari-
zona 85287, USA
1 K.-P Schade and Th. Hädrich, 3th International conference on multiphase flow, ICMF’98,
Lyon,France, June 8-12 ,(1998).
2 M. Sommerfeld and N. Huber, Int. J. Multiphase Flow 25,(1999).
3 J. Kussin and M. Sommerfeld, Experiments in Fluids 33,(2002).
4 Y. Tsuji, T. Oshima and Y. Morikawa, KONA 3,(1985).
5 M. Sommerfeld, Int. J. Multiphase Flow 18,(1992).
6 M. Sommerfeld and J. Kussin, Powder Technology 142, 180-192 (2004).
7 Xia Zhang and Lixing Zhou, 5th International conference on multiphase flow, ICMF’04, Yokohama,
Japan, May 30 - June 4, 162 (2004).
8 Sommerfeld, 11th Workshop on two-phase flow predictions, Merseburg, Germany, April 5-
8 ,(2005).
9 A. Konan, O. Simonin and J. Adou, 11th Workshop on two-phase flow predictions, Merseburg,
Germany, April 5-8, (2005).
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