Computational Simulation Of The Depth Development Of Corrosion Pit In The Oil-tank Bottom

Pitting corrosion happens on the tank bottom inevitably due to the sedimentary water andother reasons. Pitting is one of the most serious corrosion forms, thus it’ll be very seriousonce the perforation happens to the tank bottom. Therefore, it’s very important to makenumerical simulation of the tank bottom, and to get how the pit develops.The impact factors and the reans why pitting corrosion happens are analysed. Themechanism of metallic materials, especially the one of the carbon steel’s is analysed. Acomprehensive comparison of some research at home and abroad in pitting corrosion is made,and is illustrated in both experiment research and numerical simulation. Therefore, CellularAutomaton having unique advantages in the simulation of complex physical phenomena ischosen to make the research in pitting corrosion on the tank bottom, and the pitting corrosionlaw is finally get. To check whether the model buit with CA is correct, a pitting experiment isdesigned using A3steel which is often used in the central plate of tank bottom. A Carl ZeissAxio Imager microscope is used to observe pitting morphology. The pitting morphology ofA3steel is analysed, and is compared with the one get by the model with CA, and therefore,it’s found that both two are very similar, making sure CA is feasible and effective insimulating the pitting corrosion.The final result shows that at the micro perspective, compared to the Von. Neumannneighbor, the pit diameter is bigger and the pit develops faster get with the CA model usingMoore neighbor. But at the macro perspective, the results are almost all the same. Becausethe CA model using Moore neighbor can best simulate the actual pitting, in the followingresearch, the Von. Neumann neighbor is no longer used. The final results show that, with theincrease in the time step, the pit depth is getting deeper; the pit diameter is getting bigger; the corrosion area is growing bigger; and the corrosion damage is getting worse. Also, in thesame time step, the bigger the Ppasand Pdis, the pit gets deeper, and the pit diameter getsbigger, and also the corrosion damage gets worse. What’s more, the bigger the Ppas, thesurface pit diameter gets bigger, that is a bigger pit can be seen. Therefore, the law that howthe pit develops on the bank bottom can be get with the CA model.