Air-side thermal hydraulic performance of offset strip fin aluminum heat exchangers

Experimental studies on the air-side heat transfer and pressure drop characteristics for 16 types offset strip fins and flat tube heat exchangers were performed. Parameters including fin space s, fin height h, fin thickness t, fin length l and flow length d, a series of tests were conducted in region of air-side Reynolds number 500–7500, at a constant tube-side water flow rate of 2.5 m3/h. The air-side thermal performance data were analyzed using the effectiveness-NTU method. The heat transfer coefficients and pressure drop data with different fin space s, fin height h, and fin length l were reported in terms of frontal air velocity. The general correlations for Colburn j-factor and Fanning fraction f-factor were derived by regression analysis and F significance test. The correlations for j and f factors can predict 95% and 90% of the experimental data within ± 10%. And the average deviations of predictive data for the j and f factors are 0.2% and 1.2%, mean deviations are 4.2% and 5.3%.