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.

Ship Shaft-Rate Electric Field Signal Denoising Method Based on VMD-MSS

“…Research on the shaft-rate electric field of ships has been started since the 1960s [4], but limited by the accuracy of the sensors and the acquisition technology at that time, most of the results were concentrated in the directions of model simulation [5,6], characteristic analysis [7,8] and anti-corrosion current suppression [9,10], and there was no great progress in the detection capability. Only in recent years have the advancements in signal processing methods and detection techniques revitalized the study of ship's electric field signals.…”

Analysis of Characteristics of the Electric Field Induced by an Angularly Rotating and Oscillating Magnetic Object

“…The static electric field signal generated by corrosion and anti-corrosion currents is easy to track and locate due to its obvious near-field characteristics and high signal-to-noise ratio. Therefore, it is often used for end positioning of positioning systems, mine electric field fuses, and underwater array detection [1][2][3][4][5]. In recent years, attention has been widely paid to electric field detection.…”