Influence of Specimen Profile Geometry on Fluid Dynamics in Rotating Cage Systems

The rotating cage technique has been widely used in the oil and gas industry to assess the vulnerability of materials in corrosive environments. However, it is widely accepted that this method is highly conservative—particularly regarding the equation used to calculate wall shear stress and the non-uniform distribution of these stresses on the specimen surfaces, as verified in both experimental and numerical studies. Recently, one of the most discussed aspects concerns the geometry of the specimens. Modifications in the number and dimensions of the samples have been proposed to evaluate their impact on the uniformity index of shear stress on the specimen surfaces. Accordingly, this study aims to evaluate, using computational fluid dynamics, the influence of specimen profile shape on the distribution of shear stress on the sample surfaces, in order to improve the understanding of the fluid dynamic behavior around the specimens. Five hydrodynamic profile models were analyzed, which are defined by combinations of rounded and sharp edges, length, and thickness. The results suggest that hydrodynamic profiles yield more uniform wall shear stress distributions. Profile 3, which has both edges profiled, achieved the highest wall shear stress uniformity index, reaching 93.3%.