Development of a Collision–Deposition–Removal model and study on deposition behaviors in lead–bismuth eutectic wire-wrapped rod bundles

Particle deposition in lead–bismuth eutectic (LBE) cooled fast reactors severely compromises safety and efficiency. Conventional wall models exhibit limitations in accurately describing the complex coupling effects of particle collision, rebound, rolling, sliding, adhesion, and removal under operational conditions. To address this deficiency, this study innovatively develops a Collision–Deposition–Removal coupled boundary model via secondary development based on collision theory and particle removal theory, which can clearly capture various states of particles after collision with the wall. In this study, we conducted detailed sensitivity analysis of the model and explored the governing mechanisms of particle properties, fluid parameters, and particle forces on deposition behaviors. Systematic investigations reveal: The Saffman lift force universally enhances deposition across all particle sizes (≤80% max), whereas buoyancy and virtual mass forces exhibit size-dependent deposition promotion (for dp > 16 μm and dp < 32 μm, respectively). The particle yield stress inhibits deposition of dp > 10 μm by increasing the proportion of elastic collisions. Particle density exhibits a negative correlation with the deposition of dp < 25 μm. Fluid velocity demonstrates a dual mechanism that is contingent on particle size: it facilitates deposition through collisions for dp < 10 μm and impedes deposition through removal for dp > 20 μm. These findings establish essential theoretical foundations and provide critical design parameters for optimizing filtration systems and anti-deposition strategies in LBE reactors.