Recent advances in electrospray cooling for high-heat-flux thermal management: Mechanisms, enhancements, and challenges

The escalating power density in microelectronics necessitates advanced thermal management to transcend performance and reliability bottlenecks. Electrospray cooling (ESC), utilizing electrohydrodynamic (EHD) atomization to generate fine, charged droplets, has emerged as a superior high-heat-flux solution due to its high surface-to-volume ratio and exceptional evaporation efficiency. This paper provides a comprehensive review of recent breakthroughs in ESC technology. First, the EHD fundamentals of ESC are reviewed by linking Maxwell electric stress, interfacial force balance, Taylor-cone formation, jet breakup, and charged-droplet generation. Second, spray-mode transition is analyzed as the key bridge between electric-field-driven atomization and cooling performance, with emphasis on how cone-jet stability, multi-jet emission, and jet instabilities regulate droplet size, velocity, charge, spray distribution, liquid-film renewal, and surface rewetting. Third, heat-transfer enhancement and CHF-delay strategies are critically discussed, including working-fluid formulation, voltage–flow-rate coupling, nozzle and emitter design, and surface modification, all of which affect liquid replenishment, vapor removal, boiling regulation, and dry-out suppression. Subsequently, dimensionless correlations, numerical simulations, and physics-informed prediction approaches are evaluated to clarify the current capabilities and limitations of ESC performance prediction. Finally, key challenges and future directions are identified, including environmentally compatible dielectric fluids, stable high-throughput operation, scalable nozzle arrays, coupled liquid–vapor transport surfaces, regime-aware predictive models, and reliable system integration. This review establishes a mechanism-oriented pathway from EHD atomization to wall-side heat-transfer limits and provides guidance for scalable, reliable, and energy-efficient ESC systems for next-generation high-power electronics.