Homogenized modeling of coupled flow–heat transfer in plate heat exchangers with variable channels and flow configurations

Plate heat exchangers are widely used in energy conversion systems due to their high efficiency and compact structure. However, their complex stacked geometries and strong coupling between flow and heat transfer make high-fidelity Navier–Stokes equation-based simulations computationally expensive, while existing porous media modeling approaches often focus on either flow or heat transfer of standardized regular structures. To address these limitations, a fully coupled three-dimensional homogenized modeling approach is developed for design and simulation of plate heat exchangers with complex cross-section/layered channels, enabling the simultaneous homogenization of coupled flow and heat transfer while retaining anisotropic transport properties, interlayer differences, and macroscopic characteristics within the full 3D domain. The approach employs an equivalent anisotropic porous medium representing detailed channel structures, with the flow field described using Darcy’s law and heat transfer represented by an equivalent thermal conductivity tensor for efficient simulation of the coupled process. The approach is validated using five-layer stacked structures. ... mehrThe results show that the model performs well across geometries and conditions, with deviations within 2%/10% under moderate/large temperature differences and 5% for variable cross-section and cross-layered configurations. The computational cost is reduced by more than 97% compared with the Navier–Stokes model. The model further identifies that the cross-layered configuration can enhance heat transfer by 50%–60%. The methodology is expected to support both heat exchanger manufacturers and system designers by reducing computational effort and dependence on detailed proprietary information, while facilitating more effective interaction between manufacturers and users.