Multi-Strategy CHF Enhancement in Two-Phase Immersion Cooling for Power Modules: A Unified Framework with IGBT Validation

The increasing power density of electronic devices has made thermal management a critical bottleneck for system performance and reliability. Two-phase immersion cooling offers a promising solution but is fundamentally constrained by the critical heat flux (CHF), the limit beyond which nucleate boiling transitions to film boiling, causing catastrophic temperature escalation. This study systematically investigates CHF enhancement through five experimental groups: heating rate, pump-driven circulation, system pressure, coolant selection, and surface roughness.

Results establish a three-tier hierarchy: liquid replenishment governs accessibility to the CHF ceiling; thermodynamic headroom defines the path to reach it; and the intrinsic CHF ceiling sets the ultimate cap. Key findings include: pressure exhibits a non-monotonic CHF trend with an optimum at 2.0 bar (41.4% enhancement); aluminum surface roughness achieves 126% CHF enhancement via capillary replenishment, while silicon degrades by 20.5%; Novec 7100 and Galden SV70 reach identical CHF through distinct paths—rapid response with thermal fluctuation vs. stable evolution at higher superheat; synergistic integration of pump, coolant, and pressure on a representative heater surface achieves 215% CHF enhancement, exceeding the arithmetic sum of individual contributions. The optimized immersion cooling configuration is validated on a 600 A/1700 V IGBT module, reducing junction temperature swings by up to 33.34 °C under sustained overload compared to cold-plate cooling, with static electrical parameters remaining within specification.

This unified framework provides direct design guidelines for high-power-density immersion cooling applications.