Effects of different loads on structure stress of “L”-type large-diameter buried pipe network based on fluid-structure-heat coupling

Large-diameter buried pipeline is widely used because of its energy-saving advantage and high efficiency. In this paper, “L”-type heat pipe network was taken as the research object, 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, equivalent stress of the solid structure under different conditions were calculated, and the force characteristics of pipe network and elbow under coupled and non-coupled loads were compared. Results show the maximum equivalent stress was located at inner wall surface of the short-arm anchor end. The equivalent stress of the inner wall was larger than that of the outer wall at the same position. The stress of the straight pipe of the pipe network was mainly affected by the temperature of the fluid, whereas the stress of elbow was mainly affected by the pressure. The stress distribution of the pipe network was influenced by the temperature and pressure loads coupled and the coupling effect was stronger with the higher pressure and temperature of the medium, but the coupling effect had its limit.