THE INFLUENCE OF CORRUGATED PIPES PARAMETERS ON HEAT TRANSFER CHARACTERISTICS

In order to investigate the influence mechanism of various corrugated structures on the heat transfer of continuous annular concave-convex corrugated pipes, this paper examines the influence of corrugation height (C-h = 1 mm, 1.5 mm, and 2 mm) and corrugation width (C-w = 1 mm, 1.5 mm, and 2 mm) on the flow pattern, turbulent kinetic energy, Nusselt number, friction coefficient, and performance evaluation factor. Then, the correlation equations for Nusselt number and friction coefficient are established with different corrugated structural parameters. The results show that with the increase of C-h, the vortex number, turbulent kinetic energy, and friction coefficient in the pipe increase while Nusselt number decreases. The maximum perfomance evaluation factor is 0.90 at C-h = 1 mm. However, with the increase of C-w, the vortex number and Nusselt number in the pipe increase, while turbulent kinetic energy and friction coefficient in the pipe do not change much. The maximum performance evaluation factor is 0.87 at C-w = 2 mm. Therefore, for this type of corrugated pipe, one should choose a small C-h and a large C-w.