Preparation And Properties Of Jet-microchannel Heat Sinks With Spoiler-nanowire Micro-structure

With the requirements of heat dissipation of electronic chip in high heat exchange effSciency and reliability,the traditional heat dissipation technology has been unable to meet the requirements.Therefore,microchannel heat dissipation technology has become a research hotspot as an efficient heat dissipation method..However,the problems,such as high pressure drop and large temperature gradient,can not guarantee the uniformity of the surface temperature and seriously affect its heat transfer performance.In view of this,a method of spoiler and surface growth CuO nanowire in microchannel were proposed,and its formation mechanism and heat transfer performance were systematically studied by jet impingement.The main work in this thesis is as follows:(1)The mechanism of the spoiler column in the microchannel was fabricated by laser writing method.The influence of laser processing parameters on the structure of the spoiler column was studied.Finally,the microchannel parameters of the processing spoiler column structure were selected:laser output power 21W,scanning speed 300mm/s,scanning times 60,scanning spacing of 5 ? m,and the microchannel with spoiler structure were successfully prepared.(2)The thermal oxidation parameters were studied to the effect of growing CuO nanowires in the microchannels.Finally,the optimal experimental parameters of thermal oxidation were obtained:500 ?,6h.The obtained microchannels of the spoiler column structure were applied in thermal oxidation treatment,and the microchannels of microcomposite structure(the spoiler and the CuO nanowires)were successfully fabricated.In addition,the stability of the microcomposite structure microchannels was verified.Results shows CuO nanowires can be grown stably.(3)The microchannels of the spoiler column structure were designed and studied in the Fluent simulation.The effects of jet impingement and its under the initial crossflow on the single-phase heat transfer performance were studied systematically.Results show that the microchannel wall surface temperature is the lowest on the center position of jet impingement,the pressure is the largest,and Nu was increased with the increase of Re.Based on the initial cross flow,the wall average temperature increased as the crossflow-jet ratio increases when the total flow rate was fixed.However,the wall average temperature decreased as its ratio increases when the jet flow rate was fix ed,(4)The performance testing platform of jet and microchannel was set up.The heat transfer performance of three different heat exchange methods and smooth and spoiler-nanowire microchannels were studied in this thesis.Results show the single jet impact Nu is about 1.1 to 1.6 times that of a single crossflow Nu,and has good single-phase heat transfer performance.The average temperature of the spoiler-nanowire microchannel wall is lower 6.25%?9.57%than that of the smooth microchannel with good single-phase heat transfer performance.