Numerical modeling and simulation of particulate fouling of structured heat transfer surfaces using a multiphase Euler-Lagrange approach

A CFD-based multiphase method for the numerical modeling and simulation of particulate fouling of structured heat transfer surfaces is presented and validated using different benchmarks (turbulent particle-laden backward-facing step and channel flow) available in the literature. The proposed procedure is based on a coupling of the Lagrangian-Particle-Tracking (LPT) and Eulerian approach. Therefore, suspended particles are simulated according to their natural behavior by means of LPT as solid spherical particles, whereas the carrier phase is simulated using the Eulerian approach. Large eddy simulations (LES) are performed for fully developed turbulent channel flows at Reτ=395 with selected structured surfaces (single square cavity or spherical dimple) considering a depth/diameter ratio of t/D=0.26 and foulant particle mass loading ratios up to β=ṁp/ṁf=2×10-3 using a dynamic one equation eddy-viscosity turbulence model. These simulations demonstrate the great capabilities of the proposed method and reveal a slightly better fouling performance and thermo-hydraulic efficiency of the spherical dimple, due to the existence of asymmetric vortex structures compared to the square cavity.