Analysis of heat transfer and pressure drop characteristics in an offset strip fin heat exchanger

A steady-state three-dimensional numerical model was used to study the heat transfer and pressure drop characteristics of an offset strip fin heat exchanger. Water was the heat transfer medium, and the Reynolds number Redh ranged from 10 to 3500. Variations in the Fanning friction factor f and the Colburn heat transfer factor j relative to Redh were observed. General correlations for the f and j factors were derived, and these could be used to analyze fluid flow and heat transfer characteristics of offset strip fins in the laminar, transition, and turbulent regions. Finally, three performance criteria (j/f, j/f1/3, and JF) were adopted, and the best performance criteria for the cases Pr = 7 and Pr = 50 were chosen to be JF and j/f1/3, respectively.