Mechanical Properties and Heat Transfer Performance of Conically Corrugated Tube

Abstract

Conically corrugated tube is a new type of high-efficiency heat exchange tube. In this paper, the mechanical and heat transfer properties of conically corrugated tubes formed by the cold rolling of smooth tubes are studied through experimental measurement and numerical simulation to lay the foundations for applying the tubes in heat exchangers. The results show that while conically corrugated tube has a lower axial elastic stiffness compared with smooth tube, conically corrugated tube has a higher yield strength and ultimate strength. Unlike smooth tubes, conically corrugated tubes develop three-dimensional stresses when an axial tensile load is applied to them. In addition, the heat transfer coefficient of conically corrugated tube is 15%, 17%, and 115% higher than that of spiral grooved tube, convergent divergent tube, and smooth tube, respectively. Finally, the correlation equations of the axial stress concentration factor, stiffness equivalent coefficient, Nusselt number, and flow resistance coefficient of conically corrugated tubes are obtained for engineering application.

Large Deflection of Foam-Filled Triangular Tubes under Transverse Loading

“…Moreover, thin-walled foam-filled tube structures are widely adopted as energy-absorbing devices, owing to their high energy absorption and stable deformation. Recently, much research has focused on the energy absorption of thin-walled foam-filled tube structures with different cross-sectional shapes, including square shapes [1][2][3][4], circular shapes [5][6][7][8], octagonal shapes [9], triangular shapes [10], and other irregular shapes [11,12]. Compared with investigations of the load-bearing ability of circular and square foam-filled tubes, investigations on the load-bearing ability of triangular tubes filled with foam were few.…”