A study on Calculation Method of Antifouling System by Sea Water Electrolysis

Abstract

The antifouling system for ship hull and ocean structures by sea water electrolysis has been developed. In this system, the ClO- ions, which are effective for antifouling, is generated by the sea water electrolysis reaction caused by electric current supplied from electro-conductive coatings on the surface of ship hull or the ocean structure. In order to design a reasonable antifouling system, therefore, the technique to estimate the polarizing potential distribution and the current density distribution on the interface between sea water and electro-conductive coatings is expected.In report (1), based on the Interface Electro-double Layer theory, a finite element method for the numerical analysis of the potential field caused by the antifouling system was developed, and the validity and usefulness of which was confirmed by its application to a test tank model.For the analysis of the potential field caused by the antifouling system of a ship hull, however, it is very difficult to apply the finite element method to the semi-infinite sea water domain under water surface. Therefore, in this paper a new numerical analyzing technique by using both of finite element method (for electro-conductive coatings and Ti foil potential filed) and boundary element method (for sea water potential field) jointly is developed and the validity of which is verified by its applications to a small-size passenger boat and a steel sea water pipe, for which the antifouling systems were undertaken and the antifouling efficiency tests have been performed.