Modelling of particles deposition in an environment relevant to solid fuel boilers

The paper reports on investigation of some issues in computational modelling of deposition of solid particles on oblique walls washed by a diluted gas-particle turbulent flow. The models and approaches considered are relevant to predicting the dynamics of deposit formation (the growth rate and the shape of the deposit) on tubes and bounding walls of superheaters, heat exchangers and other equipment in which the boiler flue gas is used or processed. This application, involving relatively large particles (over 8 microns) imposes some specific constraints, but also eliminates the need to consider phenomena relevant only to smaller (sub-micron and nano-) particles. Nevertheless, a practically useful model should account for a variety of phenomena. The paper focuses on analysing the performance of a model for deposit growth and effects of temperature on deposit formation for different particle sizes while using Single Particle Tracking (SPT) for modelling the particle dispersion in the fluid flow. Specifically, the particle-sticking probability approach controlled by temperature has been evaluated for three particle sizes in the test case of deposit formation on a cylindrical probe in cross flow, compared with prior simulation results of Zhou et al. (Fuel, 86, 1519-1533, 2007). (C) 2011 Elsevier Ltd. All rights reserved.