Pressure drop, heat transfer and performance of single-phase turbulent flow in spirally corrugated tubes

The paper presents the results of an experimental study that was carried ou t to determine turbulent friction and heat transfer characteristics of four spirally corrugated tubes, which have various geometrical parameters, with water and oil as the working fluids. Experiments were performed under cond itions of Reynolds number varying from 6000 to 93,000 for water, and from 3 200 to 19,000 for oil, respectively. The results show that the thermal perf ormance of these tubes was superior compared to a smooth tube, but the heat transfer enhancements were not as large as the friction factor increases. Friction factors and heat transfer coefficient in these rough tubes were an alyzed on the basis of momentum and heat transfer analogy, and the correlat ions obtained were compared with the present data and also the results of p revious investigators; A mathematical model to evaluate the performance of spirally corrugated tube, which takes account of the large variation of flu id Prandtl number with temperature, was developed by the extension of previ ous work of Bergles and Webb. The results reported enable practical designs with standard products and optimization of tube geometry for specific cond itions. (C) 2001 Elsevier Science Inc. All rights reserved.