Analysis of mechanical-fluid-thermal performance of heat pipeline system with structural deformation effects

[Display omitted] •The deformations under burying and trench laying conditions were compared.•The deformations caused by coupled and non-coupled loads were compared.•The temperature and velocity fields under burying and trench laying conditions were compared.•The influence factor of coupling strength under different laying conditions were compared.•“L”-type heat pipeline was studied using the flow-heat-solid coupling method. Energy storage and transmission are important issues in the heating and cooling systems, chemical industry and other energy fields. The long-distance transmission pipeline system security under complex underground coupling loads was judged by structural deformation, especially the mechanical-fluid-thermal performance. A representative “L”-type heating pipeline system was selected as the research object and three-dimensional model was established to figure out the heat transfer, medium flowing and the deformation of the solid structure. The influence of coupled and non-coupled loads on deformation was also compared and analyzed. Results show that the deformation was affected by pressure and temperature loads simultaneously, which was lower under the coupled loads than the sum of the pressure and temperature loads alone. Due to the soil hindering the extension of the heat pipeline, the main affection factor was precisely the opposite, but the deformation distributions of the pipeline were not the exact opposite. The coupling strength was mainly influenced by pressure load under the burying laying condition, and the influence by temperature load could be ignored, whereas the coupling strength was influenced by both pressure and temperature loads under the trench laying condition.