Direct numerical simulation of polydisperse aerosol particles deposition in low Reynolds number turbulent flow

Aerosol behaviors have a great effect on the evaluation of the leak rate of the coolant in the concept of Leak Before Break (LBB) in the Nuclear Power Plant (NPP) as the coolant will be released into the containment mainly in the form of aerosols if there exists a leak in the primary loop. The transportation and deposition of aerosol particles strongly affect the accuracy of evaluating the leakage source term. In this paper, direct numerical simulation coupled with Lagrangian particle tracking is proposed aiming at the transportation and deposition of polydisperse micron-sized particles in low Reynolds number turbulent horizontal flow. Results are validated by several theoretical and empirical equations. The study reveals the diffusion and deposition mechanism of particles with different sizes. It indicates that gravity plays a main role in the deposition of large particles (dp > 10 μm) in the low Reynolds number turbulent flow (Re < 6000). For small particles, deposition is mainly determined by the turbulence and Brownian motion. The size distribution of the deposited particles is different with the initial particle size distribution, which indicates that the particle size distribution in the containment may be not the same as the leaked particle size distribution.