Data-Driven Design Methodology Development and Extended Experimental Validation for High-Temperature sCO₂ Precoolers: From Empirical Analysis to Engineering Applications

For horizontal takeoff and landing reusable hypersonic vehicles, thermal management of aerodynamic stagnation heat at high Mach numbers constitutes the most critical thermal challenge. Usually, the researcher addresses this through an integrated thermal allocation strategy employing lightweight high-efficiency precoolers, which systematically redistribute thermal loads by reducing inlet/outlet temperatures while enhancing energy input to power components, thereby achieving superior energy utilization efficiency. However, the ultra-fine characteristic dimensions (~1 mm scale) of modern precoolers intensify fluid-thermal coupling effects, rendering conventional design methodologies inadequate with prediction deviations exceeding 30%. To resolve this, we present an inverse design framework based on a prototype sCO₂ precooler. Through 15 meticulously designed operational cases encompassing air inlet temperatures around 800 K and CO₂/air flow ratios of 1–1.5, we establish a data-informed methodology that synergizes: (1) Experimental characterization of thermal-hydraulic performance (including heat transfer coefficients and pressure drop correlations). (2) Reverse determination of critical design parameters through integration with conventional heat exchanger design protocols. (3) Validation under representative hypersonic flight conditions. Experimental verification demonstrates that the proposed methodology reduces temperature prediction errors to <15% compared to empirical data, while maintaining pressure drop deviations within ±10%. This advancement provides a validated design paradigm for next-generation hypersonic thermal management systems requiring strong multi-physics coupling resolution.