Two-Phase Jet Impingement Cooling with Copper Inverse Opal Coated Microfins Using Novec 649

Abstract Two-phase jet impingement cooling is a promising technique for heat dissipation of high-power electronics, offering high heat transfer coefficients by directly targeting coolant onto hot surfaces. In this study, we propose copper inverse opal coated microfins (CCM) for enhanced two-phase jet impingement cooling. A dielectric fluid (Novec 649) is used as the coolant to ensure electrical insulation. Experiments are conducted on a chip-level jet impingement setup at a fixed 20 °C inlet temperature, across varying flow rates (1.5–3.5 L/min) and heating powers. A custom Polyamide manifold is integrated with the test section to enable uniform liquid delivery and to provide peripheral outlets for excess liquid and vapor discharge, thereby stabilizing the two-phase operation. Boiling curves, thermal resistances, and on-chip temperature uniformities are obtained for multiple CCM samples having different pore sizes, neck diameters, and thicknesses of the copper inverse opal (CIO) layer. Due to abundant nucleation sites and capillary wicking provided by the CIO layer, the CCM surfaces demonstrate significantly improved boiling performance, achieving high critical heat fluxes (CHF) of 181W/cm2 at a 21K superheat. The temperature difference across the 3.36 cm2 heated area at 552w power input is around 10 K, indicating excellent temperature uniformity. This work highlights the efficacy of CCM surfaces in two-phase jet impingement cooling with Novec 649, paving the way for safe and efficient thermal management of electronics using dielectric fluids.