摘要

Based on the 3-node triangular linear element and to overcome the element cross-leaf integration problem, a new 3D fast method was formulated for 3D potential problems through combination of the fast multipole boundary element method (FMBEM) with the semi-analytical algorithm of nearly singular integral, to realize the accurate calculation of the nearly singular integral in the 3D boundary element method (BEM). This method is applicable to the heat exchange of thin-wall structures of U-type buried pipe groups. In the cooling and heating conditions, the effects of the wall thickness of the U-type buried pipe group were analyzed by means of the new FMBEM, and the thermal interaction between multiple buried pipes was discussed. The calculation results show that, for a constant thermal conductivity of the pipe wall, the thicker the pipe wall is, the greater the effect on the heat exchange between the pipe fluid and the soil will be. For a constant borehole spacing, the bigger the number of buried pipes in a group is, the stronger the thermal interference between the pipes will be. The main strategy to increase the heat exchange of the pipe group is to reduce the thermal interference between the heat exchange pipes. Due to the accurate calculation of the nearly singular integral, the proposed 3D FMBEM can effectively solve the 3D heat exchange problems of thin-thick coupled bodies. This method and the results for the provide references for the engineering application of buried pipe heat exchangers. ? 2023 Editorial Office of Applied Mathematics and Mechanics.

全文