摘要
A laser-micromilling process was developed for fabricating micro pin fins on inclined V-shaped microchannel walls for enhanced microchannel heat sinks.A pulsed nanosecond fiber laser was utilized.The feasibility and mechanism of the formation of micro pin fins on inclined microchannel walls were investigated for a wide range of processing parameters.The effects of the laser output power,scanning speed,and line spacing on the surface morphologies and geometric sizes of the micro-pin fins were comprehensively examined,together with the material removal mechanisms.Micro pin fins with acute cone tips were readily formed on the V-shaped microchannel walls via the piling of recast layers and the downflow of re-solidified materials in the laser-ablation process.The pin-fin height exhibited an increasing trend when the scanning speed increased from 100mm/s to 300 mm/s,and it decreased continuously when the line spacing increased from 5μm to 20μm.The optimal processing parameters for preparing micro pin fins on V-shaped microchannels were found to be a laser output power of 21 W,scanning speed of 100-300 mm/s,and line spacing of 2-5μm.Moreover,the V-shaped microchannels with micro pin fins induced a 7%-538%boiling heat-transfer enhancement over their counterpart without micro pin fins.
基金
This study is financially supported under the Grants of the National Natural Science Foundation of China(Grant No.51775464)
and was partially supported by Basic research projects of Shenzhen Research&Development Fund(Grant No.JCYJ20200109112808109).
