Forced convection heat transfer in AlSi7Mg lattice structures fabricated by additive manufacturing

The thermal-hydraulic performance of lattice structures with different topologies and relative densities was investigated. AlSi7Mg sandwich panels cored with vertical fin, pyramidal, and tetrahedral lattices were fabricated using additive manufacturing. Four different relative densities (7.5 %, 10 %, 12.5 %, and 15 %) were considered for each lattice core. The experiment was conducted under constant heat flux and steady-state forced convection. Results showed that increasing relative density led to an increase in the average Nusselt number by 3.2-12.5 % in the vertical fin, 23.8-56.4 % in the pyramidal lattice, and 38.8-46.9 % in the tetrahedral lattice. To evaluate the efficiency of different topologies, the average Nusselt number was compared at a fixed pumping power. The pyramidal lattice exhibited the best performance among the test samples, followed by the tetrahedral lattice. The numerical analysis was performed to gain further insights into the heat transfer mechanisms involved. As the relative density increased, an increase in both the maximum fluid velocity and turbulent kinetic energy was observed in all test samples. The numerical results demonstrate that the observed improvement in thermal-hydraulic performance with increasing relative densities in experiments is attributable to the enhanced momentum of the fluid and turbulent mixing.