Skin Effect Of Thermal Transfer In Deep Water Pipelines Of Current Tracing System

In order to prevent the formation of hydrates and wax deposits,deep-water submarine pipelines must be heated and insulated.Electric heat tracing is one of the basic measures for long-distance pipeline flow guarantee,and the corresponding electromagnetic field,thermal field and flow field under the multi-field coupling conditions The thermal insulation design of the structure and the guarantee of the operation stage conditions are the research hotspots that are very concerned by the academic and engineering circles.Through theoretical analysis and numerical simulation,this paper has made the following progress:1.In order to analyze the skin effect,proximity effect and electromagnetic heat effect in the skin effect electric heat tracing technology,an electromagnetic model is established.The analysis shows that the alternating current through the heat tracing tube is concentrated on the inner surface of the heat tracing tube,and As the frequency of the alternating current increases,the skin effect phenomenon becomes more obvious,and the more Joule heat is generated.Using Maxwell,the Joule heat power generated by the skin effect electric heat tracing system can be calculated.2.In order to study the pipeline temperature field distribution when the skin effect electric heating heating pipeline reaches a stable state under normal working conditions,a steady-state analysis model of electromagnetic heat flow coupling is established.The research shows that the temperature at the heating pipe is the highest because the oil is in a flowing state As a result,the heat transfer effect is poor,and the temperature rise of the oil is not obvious.However,under normal operating conditions,the skin effect electric heat tracing technology can also ensure that the temperature of the entire pipeline is higher than the critical temperature of hydrate and wax generation.3.In order to study the heating effect of skin effect electric heat tracing on the pipeline under the state of shutdown,establish a transient analysis model of electromagnetic heat flow coupling.The research can be obtained by selecting the appropriate number of heat tracing tubes,current size and heating time,which can make The oil temperature rise effect is obvious when the pipeline is stopped,and the temperature rise at the end of the pipeline is more obvious than the temperature rise at the beginning,which solves the problem of low oil temperature at the end of the pipeline.The models and methods in this paper and related results provide an important reference for the engineering design of skin effect electric heat tracing.