Numerical Simulation Of Arc And Droplet Transfer In Underwater Hyperbaric Dry GMAW Welding

In recent years,oil and natural gas have been gradually developed and utilized more and more from the sea in order to solve the scare problem of oil and natural gas from the land.Oil and gas pipelines have been used more and more.And they need to be replaced and maintained because of the service life and the marine environment.With the exploitation increase of the depth about oil and gas pipelines and the increase of the pressure,we need a high underwater welding technology to demand the welding environment.Underwater hyperbaric dry welding technology has a strong adaptability and high welding quality to be used.Therefore,it has a promising application prospects.It is very significant to research and develop underwater hyperbaric dry welding technology of high performance.In this paper,I used the Fluent of numerical simulation software to build a mathematical model about welding arc and droplet transfer of underwater hyperbaric dry GMAW,and I dealt with numerical simulation and numerical analysis.As for the welding arc,the numerical simulation results indicated that the arc shape likes a bell-shaped.With the environmental pressure increasing,the arc shrank,the radial column size of the arc reduced,the maximum temperature of the center of the arc increased,and the pressure and the current density of the arc rose.When the environmental pressure is certain,with the increase in welding current,the shrinkage of the arc decreased,the radial column size of the arc increased,the maximum temperature of the center of the arc rose,the pressure of the arc dropped,and the current density of the arc rose.As for the droplet transfer,the numerical simulation results indicated that droplet transfer is changed in different forms,such as jet flow transfer,drop transfer,projected transfer with the environmental pressure increasing.The frequency of the droplet transition also decreased,the size of the droplet increased.When the environmental pressure is certain,with the increase in welding current,the frequency of the droplet transfer increased,the size of the droplet dropped.In this paper,I used the underwater hyperbaric dry welding test cabin to make the welding experiment done.The high speed camera system was used to test the welding arc and the process of the droplet transfer.Compared the results to the numerical simulation results,I found the results are basically the same.It verified the correctness of the numerical simulation results.Therefore,the research results of numerical simulation have directive significance for the underwater hyperbaric dry welding research.