Enhanced boiling heat transfer of FC-72 over staggered micro-pin-finned surfaces with submerged jet impingement

The experiment was made of boiling heat transfer of FC-72 on staggered micro-pin-finned chips with submerged jet impingement. The dimension of the silicon chips is 10 mm × 10 mm × 0.5 mm (length × width × thickness) on which staggered micro-pin-fins with the four dimensions (width × thickness × height, 50 μm × 50 μm × 60 μm, 30 μm × 30 μm × 60 μm, 50 μm × 50 μm × 120 μm and 30 μm × 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. The Effects of jet velocity (V_j = 0.5, 1, 1.5 m/s), nozzle numbers (n = 1, 4, 9), jet-to-target distance (s = 3, 6, 9 mm), and micro-pin-fins on jet impingement boiling heat transfer were explored. The results showed that staggered micro-pin-fins show better heat transfer performance compared with smooth surface. The critical heat flux increases linearly as jet velocity increases. At a fixed Reynolds number, all chips at nozzle number n = 4 show the lower wall temperature and higher CHF than that at n = 1 and n = 9, and at n = 1, all chips show the worst heat transfer performance. Small nozzle-to-surface distance, s = 3 mm, shows a little better heat transfer performance than that of s = 6 mm and s = 9 mm.