A CFD–Regression Surrogate Framework for Thermohydraulic Modeling of a Novel Plate Heat Exchanger

Source abstract

Plate heat exchangers are widely used in compact thermal systems, where heat-transfer enhancement must be balanced against hydraulic losses. This study develops a computational fluid dynamics (CFD) and regression-based surrogate framework for a novel plate heat exchanger (NPHE) under two working-fluid regimes. Three-dimensional finite-volume simulations were performed over Re = 500–5000 using air and water as hot-side fluids, while water was maintained on the cold side. The CFD results show that the proposed wavy geometry promotes flow redistribution and secondary-flow structures that enhance convective heat transfer. For the air-side case, an indicative literature-based comparison with a conventional 60° chevron plate heat exchanger suggests average increases of approximately 30% in Nusselt number and 56% in thermohydraulic performance index. A compact dimensionless surrogate was constructed using Reynolds and Prandtl numbers as inputs. Based on 20 CFD observations and leave-one-out cross-validation, the selected logarithmic Nusselt-number model reduced the mean absolute percentage error from 7.22% to 3.51% relative to a power-law baseline. The friction-factor surrogate achieved a MAPE of 3.51%, while the derived performance index exhibited a MAPE of 3.15%. The equations provide an interpretable interpolation for the investigated geometry, boundary conditions, Reynolds-number interval, and air–water cases without extrapolation.