Convective Heat Transfer Characteristics Between Deep Sea Oil And Gas Pipelines And External Current

With the increasing depletion of onshore oil and gas resources,deep-sea oil and gas platforms have been developed rapidly in recent years.The gathering pipelines of deep-sea oil and gas platforms include deep-sea risers and subsea pipelines.Different from the external heat dissipation process of onshore buried oil and gas gathering and transportation pipelines,the external heat dissipation of deep-sea risers and submarine pipelines is mainly convective heat transfer,which is greatly affected by surrounding waves and ocean currents.Studying the convective heat transfer features between the sea risers and submarine pipelines are of great importance to the thermal design of the gathering pipelines of the offshore oil and gas platforms.Focusing on deep-sea risers and submarine pipelines,this paper adopts the high-precision numerical solution method of large eddy simulation to study the convective heat transfer characteristics of deep-sea risers and submarine pipelines.Firstly,a convective heat transfer model outside a single circular pipe under turbulent flow is established.Based on previous literature data,the accuracy and reliability of the large eddy simulation method are verified,and the effects of computational domain,grid node number,sub-grid scale model and Reynolds number are analyzed;Secondly,the convective heat transfer process of the submarine pipeline near the seabed under the condition of free flow is studied.The results show that the gap-diameter ratio,the thickness of the boundary layer,and the Reynolds number have significant effects on the temperature field outside the tube.Then,the effects of spacing ratio,incident angle,and vortex mode on the convective heat transfer outside two deep-sea risers under wake interference are explored.Finally,convective heat transfer characteristics around a group of the deep-sea risers is studied,and the effect of arrangement is emphasized.