Effects of different loads on structure stress of “L”-type large-diameter pipeline under burying and trench conditions based on fluid-structure-heat coupling

•The stress of the surfaces under burying and trench laying conditions were compared.•The force characteristics caused by coupled and non-coupled loads were compared.•The effects of different mediums on the variables of the temperature were compared.•The temperature and velocity fields under burying and trench laying conditions were compared.•“L”-type heat pipe network was studied using the flow-heat-solid coupling method.

The research object of this paper is “L”-type heat pipe network, which was studied using the flow-heat-solid coupling method. The ANSYS Workbench platform was used to simulate heat transfer and the flow of the medium in the pipe network. The pressure and temperature of the flow field and the temperature; and equivalent stress of the solid structure under different conditions were calculated, and the force characteristics of pipe network and elbow caused by coupled and non-coupled loads under burying and trench conditions were compared. Results show that the temperature and velocity fields of the liquid domains under burying and trench laying conditions were the same, and the structure temperature distributions of the pipe network under the two laying conditions were also the same. The pressure and temperature loads were not separate from each other, thereby affecting the stress of the pipe network simultaneously, and the stress under the coupled loads was lower than the sum of the pressure and temperature loads individually. The stress distribution of the outer and inner surfaces under burying laying condition was opposite that under trench laying condition because of the soil that hinders the extension of the heating tube.

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