Experimental and numerical studies of flow field and mass transfer phenomena on sinusoidal wavy walls

The flow field and mass transfer phenomena on wavy walls are studied both experimentally and numerically for application to the pipe-wall thinning of nuclear power plant. The numerical simulations are carried out using four turbulence models and the results are compared with the velocity field on wavy planar wall measured by particle image velocimetry, and the mass transfer coefficient data on a pipe wall in literature. The near-wall velocity field of the wavy wall shows the flow separation and reattachment, and the high intensity turbulence energy generation over the recirculation region along the trough. The predictions by AKN model indicate better agreement with the experimental behavior of mean flow and turbulence characteristics on the wavy wall, while the other models fail to predict the reattachment behavior. Further attention is focused on the mass transfer enhancement behavior over the wavy pipe wall. It increases with an increased relative roughness associated with the growth of recirculation region and the increased turbulence energy. However, the growth of mass transfer coefficient saturates at large relative roughness because of the limitation of the recirculation region and the downstream shift of high turbulence energy region over the trough. The mass transfer behaviors on the wavy pipe wall are better predicted by thek-omega shear stress transport model.