Experimental study on single-phase hybrid microchannel cooling using HFE-7100 for liquid-cooled chips

Abstract

It is highly desired to efficiently dissipate the high heat flux generated in electronics. A novel hybrid microchannel heat sink combining manifold with secondary oblique channels (MMC-SOC) has been proposed and studied numerically in our previous work. The current study conducts the fabrication and experimental test of the hybrid microchannel heat sink using dielectric fluid HFE-7100. The volume flow rate qv ranges from 211 to 580 mL/min, with channel Reynolds numbers between 278 and 905 for heat fluxes q'' = 20, 25, 30 and 35 W/cm2. The results indicate that the MMC-SOC heat sink can simultaneously reduce the thermal resistance Rt and pressure drop ∆P. For heat sinks with channel height Hc = 60 μm, an 11% reduction in ∆P and a 24% reduction in Rt are obtained compared to conventional manifold microchannel (MMC) heat sink for qv = 580 mL/min and q'' = 20 W/cm2. As qv increases, the ratio (Rt/Rt0) becomes smaller and (∆P/∆P0) becomes larger, which indicates an enhanced ability of reducing Rt and a suppressed ability of reducing ∆P. For the maximum qv = 580 mL/min and q'' = 35 W/cm2, the MMC-SOC heat sink can maintain a maximum chip temperature of 53 °C with a pressure drop of only 3.77 kPa. Moreover, the proposed MMC-SOC heat sink has a lower pressure drop compared to MMC heat sink owing to a reasonable design, even though the Reynolds number of the MMC-SOC heat sink reaches up to 883. This provides a very promising scheme for safe and efficient single-phase microchannel cooling used in the thermal management of electronics with high heat flux. In addition, the ratio (Rt/Rt0) will increase with increasing heat flux and increasing the flow rate becomes an effective way to further reduce the chip surface temperature at operating conditions with higher heat flux.