engleski

A Mathematical Model for the Internal Cathodic Protection of Cylindrical Structures

Applicability of a two-dimensional mathematical model of the internal impressed current cathodic protection (CP) system consisting of two cylinder shaped electrodes was investigated by comparing the experimental potential distribution with the one predicted by the model. Current density distribution on the internal wall of the cathode cylinder was assumed uniform. The range of potentials in which this condition holds and where predominant reaction occurring on the protected structure is oxygen reduction was determined experimentally from polarization measurements. All the input parameters: anode radius, cathode radius, anode-to-cathode distance, electrolyte conductivity and limiting current density of oxygen reduction were measured quantities. Nonuniform current density distribution was calculated in the first approximation by entering the computed values of cathode polarization potential into the nonlinear cathodic polarization expression. The mathematical analysis was also extended to the case of two anodes by employing the principle of the potential fields superposition. The model was shown to be applicable to the investigated CP system with geometrical arrangement of electrodes that commonly occurs in practice.

cathodic protection; modeling; potential distribution; current distribution

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