Si₃N₄ Manifold Microchannels Cooling System for High Heat Flux Electronic Applications

The increasing energy dissipation in more compact and powerful electronic systems has led to extreme high heat fluxes which call for more effective thermal management solutions. [1] One innovative cooling strategy to meet the dissipation demand is two-phase cooling utilizing manifold-microchannels, it can achieve high heat transfer while maintaining low pressure drops in comparison to conventional two-phase microchannels. For electronics cooling in extreme environment, Si3N4-based ceramic is an ideal substrate due to its high thermal conductivity, low elastic modulus, and sufficient strength and toughness. In this study, a reduced order thermal-fluidic analysis of Si3N4 manifold-microchannel for two-phase boiling flows is conducted for dissipating up to 1 kW of heat from a 1 cm ² heated area on a compact Si3N4 sample. The effect of manifold-microchannel geometry parameters on pressure drop and heat resistance are investigated. The performances of different type of working fluids are also compared, including R134a, R1234yf, R1234ze(E), R245fa, and R1233zd, FC72, and HFE7100. The proposed manifold-microchannels with R134a as the working fluid can achieve low pressure drop ~20 kPa and low thermal resistance ~0.06 K/W with a mass flow rate requirement of 9~ 13 g/s for a heat flux of 1 kW/cm ² .