Embedded cooling with 3D manifold for vehicle power electronics application: Single-phase thermal-fluid performance

Single-phase thermal-fluidic performance of an embedded silicon microchannel cold-plate (25 parallel channels: 75 μm × 150 μm) with a 3-D liquid distribution manifold (6 inlets: 700 μm × 150 μm) and vapor extraction conduits, is investigated using water as working fluid. A 3D manifold is fabricated from silicon and bonded to a silicon microchannel substrate to form a monolithic microcooler (μ-cooler). A metal serpentine bridge (52 mm2 of footprint) and multiple resistance temperature detectors (RTDs) are used for electrical Joule-heating and thermometry, respectively. The experimental results for maximum and average temperatures of the chip, pressure drop, thermal resistance (as low as 0.68 K/W), average heat transfer coefficient (∼30,000–50,000 W/m2 K) for flow rates of 0.03, 0.06 and 0.1 l/min and heat fluxes of 60, 100 and 250 W/cm2 are reported. The embedded microchannel-3D manifold μ-cooler device is capable of removing 250 W/cm2 at a maximum temperature of 90 °C with less than 3 kPa pressure drop for a flow rate of 0.1 l/min. The results from conjugate thermal-fluidic numerical simulations agree well with the experimental data over the wide range of heat fluxes and flow conditions. The numerical simulation results also hint at the possibility of removing up to ∼850 W/cm2 using single-phase water at a maximum temperature of 166 °C at the same pressure drop and flow rate. This offers a very attractive strategy/option for cooling of high heat flux power electronics using single-phase water.