Turbulent Flow Friction and Heat Transfer Characteristics of Single- and Multistart Spirally Enhanced Tubes

Abstract

Investigations have been carried out on heat transfer and frictional characteristics of five spirally corrugated tubes of one to four corrugation starts, having the same helix angle, but of varying geometrical aspect ratios, for the turbulent flow of water and 50 percent glycerol. The thermal performance of these tubes was found to be superior compared to a smooth tube. Friction factors and heat transfer coefficients in these rough tubes were analysed on the basis of momentum and heat transfer analogy, and the correlation obtained was tested with the present data and also the published results of previous investigators. Performance evaluation criteria were used for the quantitative demonstration of the benefits offered by these spirally corrugated tubes for heat exchanger applications.