A Mathematical Model with Piecewise Nonlinear Boundary for Sacrificial Anode Cathodic Protection in Sea Water

The way of handling boundary condition not only affects the numerical potential distribution of cathodic protection system, but also affects the application of the model. According to the difference of corrosion potentials of Al-Zn-In sacrificial anode and 316L stainless steel in seawater, the appropriate polarization potential range and scan rate were chosen to measure the polarization curves used for handling boundary conditions and founding a nonlinear boundary model for the sacrificial anode cathodic protection system. The current model which does not depend on the polarization dynamic parameters simplifies the simulation for sacrificial anode cathodic protection. Numerical results of the influences of Al-Zn-In sacrificial anode placement, shape and placement mode on the potential distribution of 316L stainless steel agree well with the existing theory and thus verify the feasibility of current model.