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Journal of Flow Visualization and Image Processing
SJR: 0.161 SNIP: 0.312 CiteScore™: 0.1

ISSN Druckformat: 1065-3090
ISSN Online: 1940-4336

Journal of Flow Visualization and Image Processing

DOI: 10.1615/JFlowVisImageProc.v3.i1.70
pages 91-107

VISUALIZATION OF FLY ASH PARTICLE TRAJECTORIES WITHIN A BOILER TUBE BANK MODEL

Masud Behnia
School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney 2052, Australia
L. A. Amoroso
School of Mechanical and Manufacturing Engineering, The University of New South Wales, Sydney 2052 Australia
R. A. Platfoot
School of Mechanical and Manufacturing Engineering, The University of New South Wales, Sydney 2052 Australia

ABSTRAKT

The flow of two phase fly ash/air mixtures through a boiler tube bank within a specialized wind tunnel has been studied. Flow visualization work included photography of the particles illuminated by either laser sheets or synchronized flash units. Fluid flow structures such as trailing vortices in the wake of individual tubes may be identified from the distribution of the ash particles. Measurements of individual particle streaks on the photographs were used to determine the velocity distribution of the solid phase. Restitution coefficients for fly ash striking the steel tubes were calculated by comparing velocity magnitudes for particles prior to their impact and those following their rebound. These restitution ratios provide an indication of the kinetic energy exchange between the ash and the tube surface. The results allow an appreciation of the dependence of the restitution coefficients on the angle of impact. This was further explored with the study of ash streams impacting angled plates. The correlation of these coefficients with impact angles may be incorporated in mathematical models of both the motion of two phase flow and tube wear rates due to ash erosion.