Improving corrosion test reliability in flow loops using CFD-based numerical simulation (RIP2026-00099)

Mário Ferreira da Silva, Guillermo Vilalta-Alonso, RHUAN SOUZA, Carlos Eduardo Vieira Masalla, Eduardo Alencar, Gustavo Leitão Vaz, Robson Moura, Alysson Helton Santos Bueno, Jose Antonio Da Cunha Ponciano Gomes

Universidade Federal de São João del-Rei, Universidade Federal de Sao Joao del-Rei, Universidade Federal de Sao Joao del-Rei, Labcorr – Universidade Federal do Rio de Janeiro, PETROBRAS, Petrobras, Universidade Federal de São João del-Rei, Labcorr – Universidade Federal do Rio de Janeiro

Corrosion is a complex phenomenon influenced simultaneously by electrochemical and fluid dynamic effects. Among laboratory methodologies, the flow loop stands out as the one that most closely reproduces real pipeline flow conditions due to its geometry. Although the ASTM G170 standard mentions the use of flow loops, there is still no specific guideline defining the most appropriate geometry or testing conditions for corrosion evaluation. In this context, Computational Fluid Dynamics (CFD) becomes essential to support the design and refinement of such systems. This work presents a comparative analysis of CFD applied to the design and refinement of two corrosion flow loops: one made of Chlorinated Polyvinyl Chloride (CPVC) and the other of metallic nickel alloy piping. The CPVC piping system has an internal diameter of 23 mm, including four points for electrochemical measurements and one location to mass-loss assessment. The numerical simulation was applied to determine the ideal positioning of the test specimens downstream of a pipe bend and to define the minimum spacing between them. The results showed that the velocity field becomes fully developed approximately 1000 mm after the bend, reducing the influence of recirculation zone. Furthermore, it was verified that the perturbation created by each specimen does not propagate significantly, allowing for a reliable arrangement with a minimum spacing greater than 375 mm between probes. The analysis of the metallic nickel alloy piping flow loop investigated the impact of different test section diameters (4", 2", and 1") and flow rates on the wall shear stress (WSS) distribution. It was observed that the test sections in which the diameter expands from 1" to 4" or from 1" to 2" generate recirculation zones and significant WSS variations among the test specimens, with the first specimen being the most affected. In contrast, the constant diameter configuration (1") proved to be the most suitable, as it resulted in a uniform velocity profile and, consequently, an identical WSS distribution across all test specimens. This uniformity is essential to ensure the comparability of corrosion results. Overall, the numerical results demonstrate that CFD is a powerful tool for optimizing corrosion flow loop design, enabling precise visualization and quantification of flow phenomena that are otherwise difficult to capture experimentally. This ensures that laboratory tests are performed under controlled and representative fluid-dynamic conditions, improving the reliability of corrosion assessments.