NUMERICAL COMPUTATION OF PARTICLE-LADEN GAS-FLOWS PAST STAGGERED TUBE BANKS UNDERGOING EROSION

Erosion of tubes in tube banks by particles suspended in gas flows is a major problem in the chemical and power industry. In this paper, a numerical study has been conducted for the flow of a dilute turbulent particle-laden gas moving past two rows of staggered tubes undergoing erosion. Eulerian equations are used to describe gas-phase motion, with the turbulence viscosity evaluated from a k-epsilon model of turbulence. The prediction of impacting particle velocities and trajectories takes into account the effect of the turbulence with a stochastic particle dispersion model, as described by the authors. The particle impaction/rebound model and the erosion model of ductile alloys obtained by Tabakoff et al. are used to predict the particle rebound phenomena and the erosion damage to the tubes. The results from this study include the distributions of particle collision frequency and erosion damage to tube surfaces. The locations of maximum erosion damage to the tubes are predicted. Results indicate that the erosion damage to the second row of tubes in staggered tube banks is approximately twice that of the first row of tubes. The present paper also discusses the effect of free stream velocity and particle size on particle collision frequency and erosion damage.