Louver Pitch Research Articles

Air Side Performance of Brazed Aluminum Heat Exchangers

Extensive experiments on the heat transfer and pressure drop characteristics of brazed aluminum heat exchangers were carried out. In the present study, 27 samples of louvered fin heat exchangers with different geometrical parameters, including tube width, louver length, louver pitch, fin height, and fin pitch were tested in an induced draft open wind tunnel. Results are presented as plots of friction factor, f, and Colburn j factor against Reynolds number based on louver pitch in the range of 100 to 1000. Comparisons between the Sahnoun and Webb model and the present test data are reported and good agreements were found. By introducing “area ratio” parameters, a simpler correlation of the Colburn j factor and friction factor f were obtained. It is shown that 85% of the experimental data of heat transfer and friction data were correlated within ± 10%.

How structure in the louvered fin heat exchanger geometry

A flow visualization study of the louvered fin geometry commonly used in automotive heat exchangers was performed using a dye injection technique with 10:1 scale models. The geometrical parameters, louver pitch, louver angle, and fin pitch were varied to determine their effect on the flow structure. Tests covered Reynolds numbers of 400–4000 based on louver pitch. Data are presented in the form of a dimensionless flow efficiency (defined in terms of the mean flow angle relative to the louver angle) and Reynolds number. Correlations are developed to predict the flow efficiency as a function of dimensionless geometrical groups and Reynolds number. The flow structure is also discussed.