Linear correlation of heat transfer and friction in helically-finned tubes using five simple groups of parameters

A linear regression approach was used to correlate experimentally-determined Colburn j-factors and Fanning friction factors for flow of liquid water in helically-finned tubes. Experimental data came from eight enhanced tubes with helix angles between 25° and 48°, number of fin starts between 10 and 45, fin height-to-diameter ratios between 0.0199 and 0.0327, and Reynolds numbers ranging from 12,000 to 60,000. The current study revealed that, in helically-finned tubes, logarithms of both friction and Colburn j-factors can be correlated with linear combinations of the same five simple groups of parameters and a constant. The proposed functional relationship was tested with independent experimental data yielding excellent results.