Single-phase and boiling cooling of small pin fin arrays by multiple nozzle jet impingement

Experimental measurements of multiple nozzle submerged jet array impingement single-phase and boiling heat transfer were made using FC-72 and 1 cm square copper pin fin arrays, having equal width and spacing of 0.1 and 0.2 mm, with aspect ratios from 1 to 5. Arrays of 25 and 100 nozzles were used, with diameters of 0.25 ro 1.0 mm providing nozzle area from 5 to 20 mm(2) (5 to 20% of the heat source base area). Flow rates of 2.5 to 10 cm(3)/s (0.15 to 0.6 l/min) were studied, with nozzle velocities from 0.125 to 2 m/s. Single nozzles and smooth surfaces were also evaluated for comparison. Single-phase hear transfer coefficients (based on planform area)from 2.4 to 49.3 kW/m(2)K were measured while critical heat flux varied from 45 to 395 W/cm(2). Correlations of the single-phase heat transfer coefficient and critical hear flux as functions of pin fin dimensions, number of nozzles, nozzle area and liquid flow rate are provided.