Decoupling Thermo-Fluidic Trade-Offs in High-Reynolds-Number Flows with a Damage-Tolerant,Starfish-Inspired Dual-Channel Microlattice via Metal Additive Manufacturing

Abstract

Advanced thermal management systems in high-Reynolds-number regimes face a fundamental trade-off: enhancing convective heat transfer invariably incurs prohibitive pressure drops. To address this scaling crisis, we introduce a proof-of-concept, bio-inspired design paradigm translating the damage-tolerance principles of the starfish skeletal microlattice into a fluid impedance-matching layer. Fabricated via laser powder bed fusion, a dual-channel heat exchanger featuring a continuous converging-diverging porosity gradient was investigated. Rigorous numerical simulations and conducted physical experiments validate its fundamental performance decoupling. Compared to a uniform baseline at Reynolds number 2000, this bio-inspired structure achieves a 74.7% pressure drop reduction while increasing the Nusselt number by 12%. Crucially, an anti-gradient control group catastrophically failed mechanically and fluidically, proving that precise impedance alignment—not arbitrary aperiodicity—drives this decoupling. The superior performance is governed by an enhanced scaling law ( $Nu\propto R{e}^{0.52}$ ) driven by functional spatial segregation: accelerating core flow to maximize convection while diffusing outlet flow for pressure recovery. Concurrently, the design replicates its biological archetype’s progressive collapse, achieving a specific energy absorption of 22.86 J/g. By synergistically optimizing thermo-fluidic and mechanical properties, this work establishes a robust framework for designing high-flux multifunctional metamaterials.