Examination of Impaction Efficiency of Sea-salt Particle for an Airborne Sea-salt and a Corrosion Sensor Using CFD Model

Aiming to an improvement for estimating deposition distributions of sea-salt particles at surfaces of a structure, including an airborne sea-salt and a corrosion sensor, we performed numerical simulations for approaching flows with particles around a vertical-flat plate, which is a typical object and mimics a sensor with a support plate, by using a CFD model based on a URANS. After validation and verification through comparison with existing studies for flows with particles around a cylinder, we examined changes in particle impaction efficiencies to the plate with the approaching flow directions（0, 45 deg）and particle diameters. The impaction efficiencies rapidly increase with particle diameters, while the flow direction effects are small. Such increases in impaction efficiencies are due to contributions of inertial impaction, and thus the Stokes number with the flow speed and the plate size is available for predicting the flow and particle conditions of the increases in impact efficiencies. The efficiencies of small particles on the plate are apparently large compared with those on a cylinder; the impactions of small particles on the plate are locally activated with flow separations around a bluff body, whereas these on a cylinder are caused by interceptions without flow separations. © 2022 Japan Society of Corrosion Engineering. All rights reserved.