Extensive experiments on the heat transfer and pressure-drop characteristics of automotive brazed aluminium heat exchangers were carried out. 18 samples of louvred-fin heat exchangers with different geometrical parameters, including tube width, louvre length, louvre pitch, fin height, and fin pitch, were tested in an induced open wind tunnel. Results are presented as plots of friction factor and Colburn j-factor against Reynolds number based on the volumetric hydraulic diameter in the range of 200 to 1,600. The comparisons between the Sahnoun and Webb model and the present test data are reported and good agreement was found. By introducing a finning factor, a simpler correlation of the Colbourn j-factor is obtained. The heat transfer data for the Colburn j-factor are correlated within 10%, and those for the friction factor are within 15%.

KEYWORDS: heat flow, motor cars, brazing, aluminium, heat exchangers, experiment, louvres, finned tube heat exchangers, geometry, testing, wind tunnels, friction factor, Reynolds numbers, comparing