CFD Modeling of Mass Transfer in the Flow Through an Orifice With ζ-f Model

Mass transfer enhancement is an important element in flow-accelerated corrosion (FAC). In the present paper the ζ-f model and a compound wall treatment have been tested for high Schmidt number mass transfer in a simple fully developed pipe flow and a flow through an orifice. The test shows that the mass transfer can be well predicted in both flows when the wall is fully resolved with the ζ-f model. The superior performance of the ζ-f model in the flow through an orifice can be attributed to avoiding the utilization of the dimensionless wall distance in the model. However, when the compound wall treatment is utilized together with the ζ-f model, mass transfer can be reasonably predicted only when u_τ = C_μ^1/4k_p^1/2 is a fair assumption, as demonstrated in the computation for the fully developed pipe flow. With the compound wall treatment the ζ-f model predicts shorter reattachment length and higher mass transfer rate in the flow through an orifice.