Effects of heat flux, mass flux and channel size on flow boiling performance of reentrant porous microchannels

• A type of Ω-shaped reentrant porous microchannels (RPMs) was developed.
• Flow boiling performance of RPMs was strongly dependent on heat flux.
• Flow boiling performance of RPMs shows a weak dependence on mass flux.
• Boiling heat transfer of RPMs did not show a monotonic dependence on channel size.

Flow boiling within advanced microchannel heat sinks provides efficient and attractive solutions for the cooling of heat-heat-flux devices. In this study, a type of porous-based microchannels with reentrant configurations is developed and tested in heat sink cooling systems. The reentrant porous microchannels (RPMs), which are constructed by porous copper powder, are fabricated by solid-state sintering method under the replication of specially designed sintering modules. Three reentrant porous microchannels with hydraulic diameters of 671 μm,786 μm and 871 μm are tested under boiling deionized water conditions at inlet temperatures of 90 °C, mass flux of 160–300 kg/m2 s. The effects of heat flux, mass flux and channel size on the flow boiling performance of reentrant porous microchannels are examined. Test results show that the two-phase heat transfer performance of RPMs was strongly dependent on the heat flux, but showed a weak dependence on the mass flux. Reentrant porous microchannels with the medium size were found to enhance two-phase heat transfer rate compared to the other two samples at moderate to high heat fluxes.