Analysis and prediction of the pressure drop in corrugated plate heat exchangers based on numerical simulations

We present simulations of flows in wavy channels, typical of corrugated plated exchangers (CPHE), using wall-resolved Large Eddy Simulation (LES) and the Reynolds Average Navier-Stokes (RANS) approach with the k − ω SST model. We consider three different corrugation angles ( β ) and a range of Reynolds numbers from 4721 to 47025. Using the LES, we analyze the evolution of the head loss across the CPHE and report that for moderate Re and β it is mainly caused by the wall-shear stress contribution, whereas at high Re and β it results from the wall-pressure contribution. Further wall-resolved LES simulations are used as a reference to assess and improve the quality of RANS modeling. The standard setting of the RANS k − ω SST model, considered as a now-day standard for RANS in the industry, clearly showed limitations for such complicated geometries, with errors for the mean pressure drop prediction, which can be as high as 40 %. Finally we show that, relying on genetic algorithms, we can find sets of model parameters able to significantly reduce the RANS errors on the pressure drop although some discrepancies in the prediction of the mean flow structure remain, emphasizing the inherent limitation of the k − ω SST model.