Entropy generation minimization of a double-pipe pin fin heat exchanger

Pin fins are widely used as effective elements for heat transfer enhancement. For this reason, extensive work is being carried out to select and optimize pin fins for various applications. Any optimization procedure would lead to desirable results only if the parallel heat transfer and pressure drop are considered. In the present study, the heat transfer and pressure drop characteristics of a double-pipe pin fin heat exchanger have been experimentally derived. The empirical correlations previously validated with the experimental data were used in order to develop a mathematical model for the optimization of the actual heat exchanger. The optimization model was developed on the basis of the entropy generation minimization for different heat exchanger flow lengths and different pin length. The conclusions are derived on the basis of the behavior of the entropy generation NS number as a function of Re. It is shown that not all definition forms for the entropy generation number leads to the right conclusions.