170 likes | 313 Views
Numerical simulations of particle deposition on super-heaters. A fundamental study Oslo, 2010.02.16 Nils Erland L. Haugen. Introduction. Main focus: Particle inertial impaction No thermophoresis, eddy diffusion or Brownian motions This work has been done under the NextGenBioWaste project.
E N D
Numerical simulations of particle deposition on super-heaters A fundamental study Oslo, 2010.02.16 Nils Erland L. Haugen
Introduction • Main focus: Particle inertial impaction • No thermophoresis, eddy diffusion or Brownian motions • This work has been done under the NextGenBioWaste project
Simulations • Direct Numerical Simulations (DNS) are used • No modeling • No filtering • All space and time scales are resolved • Including the thin but important boundary layer around the cylinder • The Pencil-Code • 128 CPUs
Particle impaction (0.01<St<0.3) Re=420 Re=20 Re=6600
Front side impaction efficiency Classical impaction Boundary stopping Boundary interception
GKS (MSWI in Schweinfurt, Germany) Super heater fluid specifications:
GKS particle impaction Re=20 Re=1685 Re=420
Impaction efficiency as function of particle diameter Three orders of magnitude
Impaction rate Particle mass density pr. bin (independent of bin size)
Conclusion • DNS is required in order to resolve the important boundary layer • Both the front and the back side impaction depends strongly on Reynolds number • The total mass impaction rate at the super-heater of the GKS plant is totally dominated by particles larger than ~30 microns
Single cylinder vorticity Re=20 Re=6600 Re=420
Particle impaction (0.4<St<40) Re=420 Re=20 Re=6600