Enhanced heat transfer characteristic of micro-pin-finned surfaces with jet impingement

The boiling heat transfer on staggered micro-pin-finned surfaces with jet impingement was experimentally studied. The dimension of the silicon chips is 10 mm ×10 mm×0.5 mm (length×width×thickness) on the surfaces of which staggered micro-pin-fins with the four dimensions (width×height, 50 μm×60 μm, 30 μm×60 μm, 50 μm×120 μm and 30 μm×120 μm, named S-PF50-60, S-PF30-60, S-PF50-120, S-PF30-120) were fabricated by using the dry etching technique. In the experiment, FC-72 was used as working uid, the jet velocities were 0.5, 1 and 1.5 m·s^-1, nozzle numbers were 1, 4, and 9, jet diameters were 3, 1.5 and 1 mm, and jet-to-target distances were 3, 6, and 9 mm, respectively. The staggered micro-pin-fins show better heat transfer performance compared with smooth surface. The critical heat ux increases as jet velocity increases. In the nucleate boiling region, chip S-PF30-120 shows the highest heat transfer coefficient and critical heat flux. Meanwhile, the results of different heat transfer modes were compared, including pool boiling, ow boiling, jet impingement and flow-jet combined boiling heat transfer.