Investigations on the Condensation Heat Transfer Performance of Stainless Steel Edge-Shaped Finned Tubes

Abstract

The third-generation enhanced heat transfer technologies, such as three-dimensional fin and dimple, are still important means of improving energy efficiency. This paper analyzes the condensation heat transfer performances of three edge-shaped finned tubes that were fabricated using the plowing–extruding process. Experimental results show that the shell-side heat transfer coefficient decreases with increases of heat flux and temperature difference between wall and vapor. The edge-shaped finned tubes exhibit better heat transfer performance than smooth tubes. At the identical temperature difference between the wall and the vapor, the shell-side heat transfer coefficient of the edge-shaped finned tubes is approximately 1.7–2.6 times larger than that of the smooth tubes. At the identical temperature difference between the wall and the vapor, the shell-side heat transfer coefficient of edge-shaped finned tubes is also higher than the reported value in the literature. The excellent performance of the edge-shaped finned tubes comes from the coordination of enhancement from the three-dimensional fins, dimples, and grooves. Finned tubes with grooves fabricated along the left direction have higher and thinner fins and therefore show better heat transfer performance. The shell-side heat transfer coefficients of edge-shaped finned tubes increase with plowing–extruding depth and feed increasing.