THE EFFECT OF HELIX AHGLE ON THE PERFORMANCE OF ROPED TUBES
In the last few years, there has been a developing interest in the use of profiled or "roped" tubes to increase the heat transfer performance of condensers. Although there are well-developed manufacturing techniques for the production of these tubes, there are as yet no precise details of the most suitable profile for any particular application. This paper describes an experimental programme to investigate one aspect of roped tube performance, namely the effect of helix angle.
Experiments were carried out in which steam was condensed on the outside of a single horizontal tube. A plain tube and two roped tubes of equal pitch but differing helix angle (l8° and 44°) were tested. The roped tubes had two and six starts respectively. The heat transfer and pressure drop properties of each tube were measured. The two start tube in particular was found to give significantly improved performance over the plain tube.