0
Research Papers: Multiphase Flows

Numerical Simulation of Coal Fly-Ash Erosion in an Induced Draft Fan

[+] Author and Article Information
Franco Rispoli

Dipartimento di Ingegneria
Meccanica e Aerospaziale,
Sapienza University of Rome,
Via Eudossiana, 18,
Rome I-00184, Italy

Anthony G. Sheard

Fläkt Woods Limited,
Axial Way,
Colchester CO4 5AR, UK

Paolo Venturini

Dipartimento di Ingegneria
Meccanica e Aerospaziale,
Sapienza University of Rome,
Via Eudossiana, 18,
I-00184 Rome, Italy

Contributed by the Fluids Engineering Division of ASME for publication in the JOURNAL OF FLUIDS ENGINEERING. Manuscript received September 3, 2012; final manuscript received March 28, 2013; published online June 5, 2013. Assoc. Editor: Francine Battaglia.

J. Fluids Eng. 135(8), 081303 (Jun 05, 2013) (12 pages) Paper No: FE-12-1425; doi: 10.1115/1.4024127 History: Received September 03, 2012; Revised March 28, 2013

Induced draft fans extract coal-fired boiler exhaust gases in the form of a two-phase flow with a dispersed solid phase made of unburnt coal and fly ash; consequently fan blades are subject to erosion causing material wear at the leading edge, trailing edge, and blade surface. Erosion results in blade material loss, a reduction of blade chord, and effective camber that together degrade aerodynamic performance. This paper presents a numerical study of the erosive process in an induced draft fan carried out by simulating the particle laden flow using an original finite element Eulerian-Lagrangian solver. The particle trajectories are calculated using a particle cloud tracking technique that considers drifting near wall and an algebraic erosion model. The numerical study clarifies the influence of fan operation to the determination of the erosion regimes and patterns. In particular, the study investigates the role played by the size and mass distribution of the particles by considering a real composition of the flying ashes in the exhaust flow from a coal-fired boiler. The results illustrate the critical blade areas and erosion rates as given by the particle dynamics of different sizes. A specific analysis of the material wear at the blade leading edge is also given.

Copyright © 2013 by ASME
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Fig. 1

Sketch of the axial induced draft fan considered

Grahic Jump Location
Fig. 2

Small particles: size classes, composition, and mass distribution [29]

Grahic Jump Location
Fig. 3

Coarse particles: size classes, composition, and mass distribution [29]

Grahic Jump Location
Fig. 4

PCT approach: trajectory, cloud size, and particle distribution (colored area) at different time instants

Grahic Jump Location
Fig. 5

Cloud velocity distribution during the impact

Grahic Jump Location
Fig. 6

Computational grids of fan rotor: (a) tetrahedral mesh and (b) hexahedral mesh

Grahic Jump Location
Fig. 7

Percentage distribution of number of particles and mass in each size class

Grahic Jump Location
Fig. 8

Static pressure contour on suction (left) and pressure (right) sides with some streamlines

Grahic Jump Location
Fig. 9

PFS fan particles cloud trajectories (spheres) and streamlines (orange lines). Rear view.

Grahic Jump Location
Fig. 10

Trajectories of clouds of different particle size classes

Grahic Jump Location
Fig. 11

Impact frequency of different size classes after 10,000 h of operation (left: pressure side; right: suction side): (a) 0.75 μm; (b) 15.0 μm; (c) 52.5 μm; (d) 82.5 μm; (e) 112.5 μm; and (f) 135.0 μm

Grahic Jump Location
Fig. 12

Global impact frequency after 10,000 h of operation: pressure side (left) and suction side (right)

Grahic Jump Location
Fig. 13

Eroded mass due to different size classes after 10,000 h of operation (left: pressure side; right: suction side): (a) 0.75 μm; (b) 15.0 μm; (c) 52.5 μm; (d) 82.5 μm; (e) 112.5 μm; and (f) 135.0 μm

Grahic Jump Location
Fig. 14

Global eroded mass after 10,000 h of operation: pressure side (left) and suction side (right)

Grahic Jump Location
Fig. 15

Blade sections used for the evaluation of the effect of particle size classes on the erosion of the leading edge

Grahic Jump Location
Fig. 16

Normalized angular position along a blade profile

Grahic Jump Location
Fig. 17

Leading edge: predicted eroded thickness after 10,000 h of normal operations. Contribution given by each particle size classes (left), and global eroded thickness (right), in sections S1, S2, S3, and S4 (from top to bottom). PS = pressure side, SS = suction side.

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In