Analysis of boiler-tube erosion by the technique of acoustic emission - Part I. Mechanical erosion

This paper investigates the mechanical erosion of the metal tubes in bagass e-fired boilers with the aid of the acoustic emission technique. By studyin g the material removal under various collision conditions, the paper analyz es the dependence of the erosion wear upon the impact angle, velocity, size and concentration of the particles. It was found that the material removal mechanisms were mainly dependent on the particle collision angle and fell into four regimes characterized by rubbing and scratching, cutting and crac king, forging and extrusion as particle collision angle and fell into four reg well as sputtering and adhesion. The highest wear rate took place with the cutting and cracking mechanism when the particle collision angle was in the range of 20-30 degrees. The variation of the acoustic emission energy confirmed the conclusions. Finally, three simple formulae were developed to show the dependence of the erosion wear upon the main erosion parameters. (C) 2001 Elsevier Science B.V. All rights reserved.