Electrochemical characterization and CFD simulation of flow-assisted corrosion of aluminum alloy in ethylene glycol–water solution
By Xu, L.Y. & Cheng, Y.F.
Published in Corrosion Science
2008
Abstract
An impingement jet system was used to study flow-assisted corrosion (FAC) of 3003 aluminum (Al) alloy in ethylene glycol–water solutions that simulates the automotive coolant by corrosion potential and electrochemical impedance spectroscopy (EIS) measurements as well as computational fluid dynamics (CFD) simulation. The effects of solution pH and fluid impact angle on Al FAC were determined. An increase of solution pH enhances the activity of Al due to dissolution of Al oxide film in alkaline environment. Moreover, Al activity decreases with the increasing fluid impact angle to the specimen. A CFD simulation shows that, with the increase of impact angle, the electrode area under high-velocity flow field decreases and that under low-velocity flow field increases. Consequently, the shear stress generated on electrode surface and the resultant mechanical effect on electrode activity decreases. Therefore, the electrode is more stable than that impacted at a smaller impact angle. There is an essential role of fluid hydrodynamics in corrosion of Al electrode, which is confirmed by corrosion potential and EIS measurements as well as CFD analysis.