OPTIMIZATION DESIGN OF ICCP SYSTEM FOR SHIP HULLUSING PHYSICAL SCALE MODELING

摘要

The goal of impressed current cathodic protection (ICCP) design for ship hull is to provide arnuniform potential distribution over the hull surface during all operational aspects of an active ship,rnavoiding both underprotection and overprotection. The physical scale modeling (PSM) technique wasrnemployed to examine the effect of cathodic protection system configuration upon operating potentialrndistribution of hull underwater. A one hundredth scale painted metal model of a ship hull, fitted withrntwo propellers, was protected by ICCP in sea water diluted to an electrical conductivity one hundredthrnthat of standard sea water. Laboratory physical scale model testing was utilized to determine optimalrnplacement of ICCP components (anodes and reference cells) and to evaluate performance ofrnsingle-zone and two-zone control-type system of ICCP for the 4% wetted hull coatings loss. Analysisrnresults from a single-zone ICCP system show that the shape of the potential profile is determined byrnanode location and number, the level of which is determined by the setting of the reference electrode.rnThe data also shows that double-zone ICCP system configuration can remains stable potentialrndistribution with minimum variation for the ship hull and achieve an improved design over single-zonernICCP system.