Effects of fluid flow on corrosion behaviour in pipe bends

Abstract

Correlation on flow induced corrosion (FIC) for straight pipes and bends have been obtained by researchers via a two-dimensional numerical method and experimental techniques. However, for pipe bends, the correlations require further improvements as the flow in bends are more complicated. The objective of this research is to obtain more accurate correlations for FIC in bends using twodimensional and three-dimensional numerical and experimental techniques. In the numerical and experimental approach, several important parameters such as Reynolds number and selected discrete particle model (DPM) were used to obtain erosion rate for miter and smooth bend models. Validations for the modellings were compared with experimental results and locations of the eroded sections were observed to be in agreement. Then, the erosion rates were extracted and analyzed using shooting method. Finally, the new coefficients for the correlations were obtained. When the new equations were applied to the same two-dimensional models, it was shown that the previous two-dimensional models had over-predicted the mass transfer values. Furthermore, when comparisons were made between smooth and miter bends results under the same flow conditions, it was observed that mass transfer values calculated from miter bend models were much higher than that of smooth bends. Experimental results also showed similar behavior, when the surface morphology was examined under Field Emission Scanning Electron Microscope (FESEM). From numerical and experimental approach conducted, it is concluded that the inner diameter bends were the areas with the highest FIC behaviour for 300 and 450 smooth and mitre bends.