Thermal Performance Analysis of Lattice Structures Using Interface-Based CFD Metrics

This paper presents a detailed computational study on the convective heat transfer characteristics of three lattice topologies Cube, AFCC, and Auxetic using ANSYS Fluent simulations. For each topology, a single unit cell with a side length of 10 mm was modeled across relative densities from 10% to 80% in 10% increments [based on geometric constraints]. The fluid domain was subjected to low velocity laminar airflow, while a constant temperature of 312 K was applied at the solid base to impose thermal loading. Thermal performance was quantified using the composite metric hA_Interface, defined as the product of the convective heat transfer coefficient h and the fluid-solid interface area hA_Interface. This metric captures the combined influence of surface area and convection efficiency, providing a direct measure of total convective heat transfer capacity. Results show distinct trends across topologies, Cube lattices display a steady decline in hA_Interface with increasing density, AFCC lattices exhibit higher overall performance with peak values at intermediate densities, and Auxetic lattices achieve the strongest enhancement at 30-40% density before exhibiting sharp reductions at higher fractions due to severe flow restriction. Together, these results establish a comparative dataset of lattice-dependent thermal performance and identify optimal density ranges for each topology. The findings provide a practical framework for selecting lattice geometries in heat exchanger and heat sink applications and serve as a foundation for multiscale topology optimization of thermally graded structures.