Development of a physics-informed coarse-mesh method and applications to the thermohydraulic analysis of rod bundles with mixing vane spacers

The efficient and accurate analysis of fluid flow and heat transfer in large-scale complex tube bundle structures is of great significance for the optimal design of energy systems. To address this challenge, this paper proposes a physics-informed coarse-mesh method (PICM). In a representative application involving thermohydraulic analysis of reactor fuel rod bundles with mixing-vane spacers, this method reduces the computational time by approximately three orders of magnitude while maintaining accuracy. In detail, the PICM method avoids the explicit modeling of detailed structures such as spacers and employs coarse meshes to capture the main geometric features of tube bundles. The wall source terms are corrected by empirical correlations based on lumped parameters. The spacer-induced pressure loss and wall heat transfer enhancement are implicitly simulated by additional models. The virtual momentum source terms are adopted to reproduce the flow-sweeping effects. Experimental validation confirms that the PICM method exhibits excellent geometric adaptability, enabling efficient and accurate simulations for various tube bundle structures. This research offers an efficient numerical analysis method for large-scale complex tube bundles in energy systems and provides a new direction for the refinement development of reactor subchannel analysis.