I was wondering if anybody knows anything about modelling erosion within PHOENICS. For example, fluid flow through an elbow, what would be the erosion of the metal?

If you use the Lagrangian technique (GENTRA), the cause of erosion can usually be determined from the predicted particle distribution and flow patterns within the elbow.

If quantitative information is needed, the next stage would be the introduction of an erosion model. The approach usually adopted in CFD is to create a simplified model wherein the rate of erosion is made a function of the particle mass flux and impact velocity vector. This has been the subject of many CFD studies and most models are based in some way on the theory developed by Finnie (Wear, Vol. 3, p87-103, 1960) and Bitter (Wear, Vol.6, Part 1 p5-21, Part 2 pgs 169-190, 1963). Professor Humphrey wrote a very good review article on the subject in: Int. J. Heat and Fluid Flow 111, 170-195, (1990).