Prediction of the friction factor for the offset strip-fin matrix

This work presents an analytical model and a semi-empirical correlation to predict the friction factor in the offset strip-fin matrix. Previously reported data on eight test sections were used to test the model and to develop the correlation. The analytical model assumes laminar flow and is based on a numerical solution for zero-thickness fins. It predicts 90% of the data below a Reynolds number of 2000 within + or - 10%. At higher Reynolds numbers the predicted values show increasing error because of vortex shedding in the wake, which is not accounted for by the laminar model. A semi-empirical correlation is developed that predicts 93% of the data within - 10% in the range 300 Re 3600.