Prediction model and optimization framework for dryout threshold based on vertical micropillar architecture

• Gravity-capillary model for vertical micropillar evaporators predicts 3.9 kW/cm2. • High predictive accuracy: 3.7% error (uniform heat flux); ∼10% error (hotspots). • Optimal spacing ratio (∼0.35) maximizes heat-fluid coupling efficiency. • Framework guides high-performance wick design across diverse heat flux conditions. The escalating power density and localized hot spots in modern electronics necessitate advanced thermal management solutions. This study introduces a groundbreaking gravity-capillary coupled model for vertical micropillar-based vapor chambers, leveraging their capillary self-pumping and phase-change cooling capabilities to surpass conventional horizontal designs. The model achieves exceptional predictive accuracy, with errors of 3.7% for uniform heat flux and approximately 10% for hot spot conditions, enabling precise determination of dryout thresholds. An optimal spacing ratio of ∼0.35 yields a dryout heat flux of 3.9 kW/cm 2 . By integrating gravity-capillary theory with geometric optimization, this work establishes a comprehensive framework that elucidates heat-fluid coupling mechanisms in vertical evaporators, providing a robust foundation for designing high-performance thermal management systems under diverse heat flux scenarios.