Abstract
Coupled differential equations that are difficult to solve, yet have predictive value, will arise when modeling a combination of general and localized corrosion in the presence of flow. These equations are impossible to solve if the flow is turbulent. By making the equations dimensionless, certain groups arise that can show the relative magnitudes of the processes involved. Three dimensionless groups arise from modeling the localized area. These show the ratios of the magnitudes of migration to diffusion, convective mass transport to diffusive mass transport, and surface reaction rate to mass transfer rate. The meanings of the groups are independent of geometry and flow conditions. These groups can provide a “back-of-the-envelope” type of guidance for experimental design and corrosion prediction even though the equations from which they are derived cannot be solved.
