Experimental Study of Aerodynamic Resistance of Staggered Equilateral Banks of Tubes with Spiral Aluminum Fins

Abstract

Aerodynamic resistance of six four-row tube banks in isothermal air cross-flow is studied. The banks assembled from full-scale bimetallic tubes, the aluminum fins of which are rolled on a bearing steel tube with a diameter of 12 mm and a wall thickness of 1.25 mm. The tube spacing in the bank lattices was varied from 28 to 50 mm. The resistance of the banks is stratified depending on the spacing of the tubes even though they are geometrically similar. The experimental data are generalized by a single similarity equation in the Reynolds number range 2000–10000. Tight (compact) tube banks have the maximum thermal efficiency.