<p style="text-align: justify">Two-phase jet impingement can be particularly effective for removing extremely high heat flux from local hotpots. Due to its normal incident flow-field, jet impingement flow field has thinner hydrodynamic boundary layer. This results in greater&nbsp;local flow velocity and provides greater&nbsp;heat transfer coefficient (HTC) within the jet stagnation region. Besides, two-phase jet impingement method combines the advantages of the nucleate boiling heat transfer mechanism. This study investigates the stagnation zone cooling performance of a submerged jet impingement configuration while removing heat from a laser induced hotspot in a 100 nm thick Hafnium (Hf) thin film. The jet/nozzle diameter is ~1.2 mm and the normal distance between the nozzle outlet&nbsp;&amp; the heated surface is ~3.2 mm. Novec 7100 was used as coolant and the Reynolds numbers at the jet nozzle outlet were ranged from 2000 to 5000. The hotspot size is ~ 0.06 mm^2 and the heat flux ranged from 0.1 kW/cm^2 to 0.5 kW/cm^2. This heat flux range allows the investigation of both the single-phase heat transfer and the two-phase heat transfer up to critical heat flux (CHF). Temporal evolution of temperature distribution of heated surface is captured using infrared (IR) thermometry. For example, the CHF is found to be ~0.44 kW/cm^2 at Re ~ 5800, while providing HTC of ~133kW/m^2.K.</p>

Hotspot Cooling Performance for Submerged Confined Two-Phase Jet Impingement Cooling

Paper Proceedings: https://asmedigitalcollection.asme.org/InterPACK/InterPACK2021/volume/85505

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