Optimal design of a plate heat exchanger with undulated surfaces

The purpose of this study is to suggest a general method for the optimal design of a plate heat exchanger (PHE) with undulated surfaces that complies with the principles of sustainability. A previously validated CFD code is employed to predict the heat transfer rate and pressure drop in this type of equipment. The computational model is a three-dimensional narrow channel with angled triangular undulations in a herringbone pattern, whose blockage ratio, channel aspect ratio, corrugation aspect ratio, angle of attack and Reynolds number are used as design variables. To limit the number of simulations needed, the Box-Behnken technique is employed. An objective function that linearly combines heat transfer augmentation with friction losses, using a weighting factor that accounts for the cost of energy, is employed for the optimization procedure using response surface methodology (RSM). New correlations are provided for predicting Nusselt number and friction factor in such PHEs. The results are in very good agreement with published data. Finally, optimal design specifications are suggested for a range of Re for two values of the weighting factor. (c) 2008 Elsevier Masson SAS. All rights reserved.