Iterative algorithms for impressed cathodic protection systems

Sun, Weiwei; Yuan, Guangwei; Ren, Yong‐Xiang

doi:10.1002/1097-0207(20001030)49:6<751::aid-nme972>3.0.co;2-i

Cited by 10 publications

(2 citation statements)

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“…In order to find the corrosion rate at any point on a cathodically protected metallic structure submerged in an electrolyte (most frequently ground or seawater), a corrosion engineer needs to know the potential distribution over the electrolyte/structure interface. Today, the calculation of current and potential distribution is considered an indispensable means for study of cathodic protection (CP) systems and improvement of their reliability 1–25. Traditional CP design methods are mostly based on simple empirical formulas that require the use of large safety factors and rely, to a great extent, on the engineer's experience.…”

Section: Introductionmentioning

confidence: 99%

“…Modern CP design methods utilize explicit mathematical modelling. In general, the complexity of geometry and polarization behaviour of CP systems necessitates the use of numerical methods such as: the finite difference method (FDM) 1, finite element method (FEM) 2–5 and the boundary element method (BEM) 6–23. Among these methods, BEM is the most suitable for CP problems for two reasons: (i) unlike FDM and FEM, BEM requires discretization only of the boundaries of the system and not of the space occupied by the electrolytic medium and (ii) in an infinite system, discretization of the boundary at infinity is avoided by assuming an unknown constant potential at that boundary and by imposing the conservation of current between the anodes and cathodes which insures that there is no loss of current to infinity 9.…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of the uniform current density assumption in cathodic protection systems with close anode‐to‐cathode arrangement

Martinez

2010

Materials & Corrosion

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Cathodic protection modelling often involves making assumptions about geometric features and material characteristics that directly impact accuracy of solutions. In the present paper, predictive power of the model using approximate uniform current boundary condition on the cathode is validated against the model using nonlinear cathode polarization curves representative of low-carbon steel structure of common geometry, buried in soil or immersed in seawater. In order to explore the worst case scenario, the present example deals with a large diameter pipeline (Ø 1.2 m) and a wire anode (Ø 0.05 m), separated by a distance d, both embedded in an infinite space of conductivity k. The calculation is performed for the two sets of parameters -k and limiting current density of oxygen reduction, i l . For simulation of CP systems in seawater k ¼ 4.79 S/m and i l ¼ À86 mA/cm 2 and for CP system in soil, k ¼ 10 À3 S/m and i l ¼ À1.1 mA/cm 2 . The other physical parameters were identical for both systems (Tafel slopes b a ¼ 60 mV/dec, b c ¼ 120 mV/dec and equilibrium potentials f a e ¼ À700 mV, f a c ¼ À800 mV). The results were visualized to best exemplify the general trends in potential and current distributions that appear upon switch between uniform and nonlinear cathodic boundary conditions.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Evaluation of the uniform current density assumption in cathodic protection systems with close anode‐to‐cathode arrangement

Martinez

2010

Materials & Corrosion

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A BEM‐based genetic algorithm for identification of polarization curves in cathodic protection systems

Miltiadou

Wrobel

2002

Numerical Meth Engineering

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SUMMARYThe purpose of this work is to apply an inverse boundary element formulation in order to develop e cient algorithms for identiÿcation of polarization curves in a cathodic protection system. The problem is to minimize an objective function measuring the di erence between observed and BEM-predicted surface potentials. The numerical formulation is based on the application of genetic algorithms, which are robust search techniques emulating the natural process of evolution as a means of progressing towards an optimum solution.Examples of application are included in the paper for di erent types of polarization curves in ÿnite and inÿnite electrolytes. The accuracy and e ciency of the numerical results are veriÿed by comparison with standard conjugate gradient techniques. As a result of this research, the genetic algorithm approach is shown to be more robust, independent of the position of the sensors and of initial guesses, and will be further developed for three-dimensional applications.

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Relaxation iterative algorithms for solving cathodic protection systems with non‐linear polarization curves

Sun

2002

Numerical Meth Engineering

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SUMMARYThis paper discusses the calculation of potential distribution of impressed cathodic protection (CP) models with non-linear polarization curves. We propose a relaxation iterative algorithm for the nonlinear problem and prove both theoretically and numerically that this iterative sequence is convergent for any physical polarization curves. This feature is of signiÿcant importance in developing a computer code for the design of CP systems.

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Iterative algorithms for impressed cathodic protection systems

Cited by 10 publications

References 10 publications

Evaluation of the uniform current density assumption in cathodic protection systems with close anode‐to‐cathode arrangement

Evaluation of the uniform current density assumption in cathodic protection systems with close anode‐to‐cathode arrangement

A BEM‐based genetic algorithm for identification of polarization curves in cathodic protection systems

Relaxation iterative algorithms for solving cathodic protection systems with non‐linear polarization curves

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