Air-Side Heat Transfer and Friction Correlations for Flat-Tube Louver-Fin Heat Exchangers

The objective of this study is to develop an accurate, reliable, and updated predictive model for the air-side performance of flat-tube louver-fin heat exchangers. Using the most comprehensive experimental database to date—consisting of 1030 heat-transfer and 1270 pressure-drop measurements, from nine independent laboratories for 126 sample heat exchangers—$j$- and $f$-factor correlations are developed to predict the air-side performance of heat exchangers. The database is analyzed, the form of the curve fits is explored, and the predictive performance of the correlations is evaluated. The $j$- and $f$-factor correlations predict the experimental data with rms errors of 11.5% and 16.1%, respectively. Multiple regressions for a locally linearized data model were used to estimate the confidence intervals and covariances of the regression constants. A comparison to prior correlations shows the proposed correlations to provide more accurate predictions and to span a much broader parameter space than prior work. Practical utility in design and optimization, and unavoidable limitations in developing such correlations are discussed.