Mixed Electric Field of Multi-Shaft Ship Based on Oxygen Mass Transfer Process under Turbulent Conditions

Abstract

The theoretical basis for a multi-physics coupling modeling involving a turbulence flow field and a ship’s electric field was analyzed using the principles of electrochemistry and hydrodynamics. Considering the mass transfer of oxygen in the cathode reaction of electrochemical corrosion, the boundary element method was adopted to construct a corrosion electric field model for a multi-shaft ship under navigation. After dissecting the equivalent circuit resistance of the mechanical structure of a ship’s shaft, the initial phase difference of the equivalent resistance between different shafting systems of a multi-shaft ship was analyzed to reveal the regularity of variation of the ship corrosion mixed electric field, when the contact positions of the shaft grounding device were different. A ship model experiment was conducted to verify the correctness of the simulation model. As shown in the results, when the initial phase difference of two-shaft ship shafting equivalent resistance increased from 0° to 45°, 90°, 135°, and 180°, the amplitude of the ship’s mixed electric field varied by less than 3.7%, which was practically negligible. However, the amplitude of the ship’s shaft-rate electric field decreased by 8.30%, 25.4%, 50.2%, and 88.0%, respectively. Moreover, the minimum value of the shaft-rate electric field accounted for 4.11% of the maximum value. This significantly increased the difficulty of marine target detection based on electric field sensors.