Effect of Particle-wall Interaction on Graphite Dust Deposition on HTGR Steam Generator Tube

The deposition of graphite dust on steam generator (SG) tubes is a highly concerned issue for operation and maintenance of high-temperature gas-cooled reactor (HTGR), as the distribution of radioactivity is directly affected. In this paper, the computational fluid dynamics (CFD) study on graphite dust deposition on SG tubes was presented, with emphasis of the particle-wall interaction. From a view of kinetic energy dissipation, a critical capture velocity model was adopted to account for particle-wall collisions and incorporated into CFD simulation. The results show that the hit-and-stick assumption significantly overestimates the deposition rate of graphite dusts. With reasonable consideration of particle rebound, the deposition rate first increases then decreases with particle diameter increasing, showing a maximum at 3 μm. The analysis of spatial distribution indicates that largest deposition rates appear on middle rows of tubes.