Flow Morphology and Heat Transfer During Subcooled Flow Nucleate Boiling of HFE-7000 in Microchannels

Flow boiling was experimentally studied in parallel microchannels using coolant HFE-7000. Subcooled nucleate boiling was achieved under various thermal-hydraulic conditions for mass velocities ranging from G = 164 kg/m²·s to G = 3025 kg/m²·s. Local surface temperatures were measured and flow visualizations were conducted to obtain flow morphologies, boiling curves, and heat transfer coefficients during boiling process. It was found that heat transfer was significantly enhanced during subcooled flow boiling by bubble agitation of the liquid.