Numerical Investigation of Turbulent Mass Transfer in a 90° Bend

This paper presents a numerical study of local mass transfer coefficients in a 90° bend using the RNG version of k– model to include the influence of curvature on the turbulent transport. Simulations were performed for flow through a 90°, 3-D bend for Reynolds numbers of Re=13500, 90000 and 390000, Schmidt numbers of Sc=2.53 and 700 and curvature ratio,s of r/D=1.5, 2 and 2.5. Simulation results showed that the ratio of the maximum local mass transfer coefficient obtained in an elbow to the mass transfer coefficient obtained for fully developed pipe flow (Sh/Shp) decreases by Reynolds number (Re), Schmidt number (Sc) and curvature ratio (r/D). Maximum local mass transfer coefficient was observed at a distance of about one diameter downstream of the 90° elbow. Numerical analysis results were in good agreement with experimental results reported in literature.