Dynamic CFD modeling evaluation of ash deposition behavior and morphology evolution with different tube arrangements

Abstract A comprehensive CFD model is presented to investigate the deposition behaviors of ash particles with high AAEM contents. The ash deposition behaviors of deposited particles are described via the melt fraction sticking model, the critical impact velocity model coupled with the elastic–plastic deformation theory, and the critical wall shear velocity model. The morphology evolution of ash deposits is predicted by the dynamic mesh method. The effects of longitudinal tube spacing, transverse tube spacing and tube geometry are studied. The oscillatory turbulent vortices, ash particle kinetic energy, and tube arrangement have a combined effect on the fates of impacting ash particles. A large S1/D has the tendency to enhance the accumulation of ash deposits on the rear rows of tube bundles. The peak of the ash deposits on the windward side is higher at a small S2/D. Elliptical tube bundles are practically promising and feasible applications due to the reduction of vortex shedding and the alleviation of ash deposit formation.