Modelling of erosion-corrosion in practical geometries

The limiting factor in certain instances of erosion-corrosion of steel is the presence of dissolved oxygen in the solution and the transfer of this oxygen to the reacting surface. Computational Fluid Dynamics (CFD) can be used to calculate oxygen diffusion throughout the flow and its transfer to the reacting surface. This was used in a computational model to calculate wear and validated against experimental results, for the first time, of erosion-corrosion wear in a contracting-expanding geometry. It was found that in order to correctly predict erosion-corrosion wear, Sherwood number independent grids were required providing a new metric to evaluate turbulent erosion-corrosion modelling. The predicted wear profile matched very closely with experimental results and overall matching was very good. Downstream of the flow expansion, erosion-corrosion wear was under-predicted. The disparity is due to detached flow for most of this sector where under-predicted radial velocities decrease transfer of oxygen to the reacting surface. This under-prediction is apparent in the downstream section due to the larger relative magnitude of the radial velocity in this sector.