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Abstract Jet impingement can be particularly effective for removing high heat fluxes from local hotspots. Two-phase jet impingement cooling combines the advantage of both the nucleate boiling heat transfer with the single-phase sensible cooling. This study investigates two-phase submerged jet impingement cooling of local hotspots generated by a diode laser in a 100 nm thick Hafnium (Hf) thin-film on glass. The jet/nozzle diameter is ∼1.2 mm and the normal distance between the nozzle outlet and the heated surface is ∼3.2 mm. Novec 7100 is used as the coolant and the Reynolds numbers at the jet nozzle outlet range from 250 to 5000. The hotspot area is ∼ 0.06 mm2 and the applied hotspot-to-jet heat flux ranges from 20 W/cm2 to 220 W/cm2. This heat flux range facilitates studies of both the single-phase and two-phase heat transport mechanisms for heat fluxes up to critical heat flux (CHF). The temporal evolution of the temperature distribution of the laser heated surface is measured using infrared (IR) thermometry. This study also investigates the nucleate boiling regime as a function of the distance between the hotspot center and the jet stagnation point. For example, when the hotspot center and the jet are co-aligned (x/D = 0), the CHF is found to be ∼ 177 W/cm2 at Re ∼ 5000 with a corresponding heat transfer coefficient of ∼58 kW/m2.K. While the CHF is ∼ 130 W/cm2 at Re ∼ 5000 with a jet-to-hotspot offset of x/D ≈ 4.2.
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Design Improvement of a Commercial Impingement Two-Phase Cold Plate Used for High Heat Flux Applications
Heat fluxes in the data center have been increasing significantly due to the rise in advanced technologies such as Artificial Intelligence (AI), 5G, high-performance computing (HPC), and machine learning. The traditional air-cooling technology cannot handle high heat fluxes and requires a bigger heat sink; therefore, hindering high heat flux and high density in the data center. Two-phase cooling schemes are particularly appropriate for high heat flux situations because of their enhanced heat transfer coefficients and the non-linear relationship between heat flux and surface-to-fluid temperature difference. In this study, an experimental setup was developed to characterize and optimize the thermo-hydraulic performance of two-phase cooling cold plates intended for high heat flux applications. An improvement of 12% in thermal performance was obtained by cutting the original fins and creating mini-channels perpendicular to the original microchannels without a significant pressure drop penalty.
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- Award ID(s):
- 1738793
- PAR ID:
- 10338741
- Date Published:
- Journal Name:
- 2022 38th Semiconductor Thermal Measurement, Modeling & Management Symposium (SEMI-THERM)
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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