Prediction and Validation of Flow Properties in Porous Lattice Structures

Abstract

High-porosity metal foams have been extensively studied as an attractive candidate for efficient and compact heat exchanger design. With the advancements in additive manufacturing, such foams can be manufactured with controlled topology to yield highly tailorable mechanical and transport properties. In this study, a lattice Boltzmann method (LBM)-based pore-scale model is implemented to simulate the fluid flow in additively manufactured (AM) metal foams with unit cell topologies of Cube, Face Diagonal (FD)-Cube, Tetrakaidecahedron (TKD), and Octet lattices. The pressure drop versus average velocity profiles predicted by the LBM model were validated against in-house measurements on AM lattice samples with the same unit cell topologies. Based on the simulation results, a novel hybrid model is proposed to accurately predict the volume averaged flow properties (permeability and inertial coefficients) of the four structures. Convenient correlations for those flow properties as a function of porosity and fiber diameter are constructed. The effects of the AM print qualities on the flow properties are also discussed. The advantages of the hybrid model compared to the polynomial fitting approach for determining flow properties are discussed and compared quantitatively. The hybrid model and presented results are valuable for flow and thermal transport evaluation when designing new metal foams for specific applications and with different materials and topologies. The presented correlations based on pore-scale simulations can also be conveniently used in volume-averaged models to predict the macroscale flow behavior in such complex structures.

Prediction of Flow Properties of Porous Triply Periodic Minimal Surface (TPMS) Structures

“…For instance, the Kozeny-Carman equation stands out as one of the most widely recognized relations [52]. Similar to the current study, in [53], the authors examined the pressure drop as a function of velocity for lattice structures. Subsequently, they employed a modified Ergun equation to compute the permeability of the lattices.…”