Corrosion Simulation Of Seawater Pipeline System Under Multi-physical Field Coupling Condition

Seawater pipeline is widely used in ship,offshore drilling system,seawater desalination system and so on.With the development of Marine strategy,more and more seawater pipeline is used.Accurate and efficient detection of the corrosion depth of key parts of pipeline erosion corrosion can provide data for equipment maintenance,and reduce the damage of erosion damage to pipeline life,so as to ensure the safe and efficient work of seawater pipeline.Erosion corrosion,also known as wear corrosion,is a type of damage caused by corrosive liquid moving down a metal surface at a rapid rate.Pipeline erosion corrosion is widely existed in industrial production.The wall thickness of straight pipe will become thinner due to erosion corrosion,and eventually lead to perforation or damage.In addition,if the fluid transported in the pipe contains impurities,the corrosion will be further increased.In order to reduce the erosion corrosion of pipeline in the fluid containing impurities,it is necessary to study the influence of inclusion liquid and flow velocity on pipeline performance.Previous research results have shown that fluid velocity is the biggest cause of pipeline corrosion,and it is directly proportional to the average corrosion depth of the pipeline.This paper uses COMSOL fluid simulation software to model and analyze45° bend pipe,90° bend pipe,right Angle three-way pipe,equal diameter four-way pipe and variable diameter pipe.Under the condition of flow velocity of 1 m/s(A pipe with a reduced diameter is 1.8 m/s),the distribution of the fluid flow field,the maximum sea water velocity and the position of the maximum sea water velocity in the pipe are calculated by combining the turbulence model and mesh division.The results show that the maximum flow velocity of the 45° bend and the 90° bend both appear at the inner arch side of the bend.The maximum flow rates of the two kinds of right-angle equal diameter three-way pipeline and equal diameter four-way pipeline all appear on the inside of the inlet elbow;In a reduced diameter pipe,the flow rate is maximum at the reduced diameter.In addition to pipe shape parameters,construction technology will also change the pipe condition,thus affecting the fluid flow rate in the pipe.This paper analyzes the modeling of different weld residual height and flange concentricity,and simulates the position and size of the maximum fluid flow rate in the pipe under the condition of flow rate of 1 m/s.The results show that the maximum flow rate in the pipe appears at the top of the weld and the dislocation of the flange.In order to study the erosion of solid particles on the elbow,COMSOL software was used for modeling analysis.A flow rate of 16.5 m/s was used to determine the erosion track of solid particles in the pipeline and the erosion failure law of the elbow.There are three different erosion models used in this paper: Finnie,DNV,and E/CRC.The erosion wear rates of 90° pipe elbows are calculated and compared.The results show that the maximum corrosion rate of E/CRC model is minimum.