Prediction of corrosion rates of a ship under the flow accelerated corrosion mechanism

Abstract

Abstract In order to reveal the corrosion of a ship hull in flowing seawater, which is difficult to study under experimental conditions, a numerical method was adopted. Firstly, the numerical model of seawater flow field around the hull was established and computed, and the hydraulic characteristics of the flow field such as velocity, pressure, and oxygen concentration distribution were got. The distribution of oxygen has a great influence on corrosion. Generally speaking, where the oxygen concentration is higher, the corrosion rate is higher. The results show that the oxygen concentration is higher at the rear of the hull bottom surface. Next, a corrosion model was founded based on the above calculation. Through the calculation of the corrosion model, the mass transfer coefficient and corrosion rate distribution on the hull surface were obtained and the final conclusion was got flow accelerated corrosion (FAC) mechanism was revealed. The conclusion is as follows: Comparatively speaking, the corrosion rate of the middle and rear part of the bottom and the middle part of the sideboard is higher. Generally speaking, the corrosion rate increases with the increase of flow rate.