亲疏水表面换热性能及其沸腾现象的微细化研究
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摘要
本实验提出了复合方柱微结构的亲疏水强化换热表面,并对其在FC-72工质中的池沸腾换热进行研究。实验采用光滑芯片和方柱微结构高效换热PF30-60芯片作为对比组,通过使用装有显微镜头的高速摄像机对微细化沸腾现象进行捕捉。实验及分析结果表明:亲疏水表面芯片可有效提高沸腾的临界热流密度,降低沸腾起始点对应的壁面过热度,同时在相同热流密度下其壁面温度较PF30-60降低6～9 K;由于微结构区域提供数目可观的汽化核心,不断生长滑移的汽泡被困在光滑亲水通道,在亲水面及两侧微结构作用下加速汽泡的生长合并与脱离,因此沸腾换热效果得到显著提高。
The boiling heat transfer performance of FC-72 was experimentally studied on hydrophilic/hydrophobic surfaces based on micro-pin-finned structure. A high speed camera with microscope was applied to capture the micronization boiling phenomenon for the novel surfaces.From the comparison of the smooth chip and micro-pin-finned chip PF30-60(micro-pin-fins with 30μm fin side length and 60 μm fin height), it can be found that the hydrophilic/hydrophobic surfaces can efficiently decrease the wall temperature at the nucleate boiling onset, and can also decrease the wall superheat by 6～9 K in the nucleate boiling region at the same heat flux. From the boiling phenomenon of the novel surface, it can be observed that large number of nucleation sites are formed in the micro-pin-finned area, and the hydrophilic property accelerates the departure of grown bubbles.These hydrophilic/hydrophobic surfaces can not only provide enough nucleation sites, but also prompt the bubble mergence and departure, enhancing boiling heat transfer greatly.
The boiling heat transfer performance of FC-72 was experimentally studied on hydrophilic/hydrophobic surfaces based on micro-pin-finned structure. A high speed camera with microscope was applied to capture the micronization boiling phenomenon for the novel surfaces.From the comparison of the smooth chip and micro-pin-finned chip PF30-60(micro-pin-fins with 30μm fin side length and 60 μm fin height), it can be found that the hydrophilic/hydrophobic surfaces can efficiently decrease the wall temperature at the nucleate boiling onset, and can also decrease the wall superheat by 6～9 K in the nucleate boiling region at the same heat flux. From the boiling phenomenon of the novel surface, it can be observed that large number of nucleation sites are formed in the micro-pin-finned area, and the hydrophilic property accelerates the departure of grown bubbles.These hydrophilic/hydrophobic surfaces can not only provide enough nucleation sites, but also prompt the bubble mergence and departure, enhancing boiling heat transfer greatly.
引文
[1]SarangiI S,Weibel J A,Garimella S V.Effect of Particle Size on Surface-Coating Enhancement of Pool Boiling Heat Transfer[J].International Journal of Heat and Mass Transfer,2015,81:103-113
[2]Weil J J,Honda H.Effects of Fin Geometry on Boiling Heat Transfer From Silicon Chips with Micro-pin-fins Immersed in FC-72[J].International Journal of Heat and Mass Transfer,2003,46(21):4059-4070
[3]Byon C,Kim S J.Critical Heat Flux of Bi-porous Sintered Copper Coatings in FC-72[J].International Journal of Heat and Mass Transfer,2013,65:655-661
[4]曾勇,徐宏,侯峰,等.火焰喷涂型表面多孔管的性能研究[J].化工机械,2010(2):141-144Zeng Y,Xu H,Hou F,et al.Property Studies on the Flame-Sprayed Type Surface Porous Tubes of a Multilayer Bound Vessel[J].Chemical Engineering&Machinery,2010(2):141-144
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[6]Betz Amy Rachel,Xu J,Qiu H H,Attinger D.Do Surfaces With Mixed Hydrophilic and Hydrophobic Areas Enhance Pool Boiling[J].Applied Physics Letters,2010,97(14):141909
[7]Hsu C C,St T W,Chen P H.Pool Boiling of Nanoparticle-Modified Surface with Interlaced Wettability[J].Nanoscale Research Letters,2012,7(1):1-7
[8]Karrsi S B R.Dynamics of Bubble Departure in MicroGravity[J].Chemical Engineering Communications,1988,70(1):127-135
[2]Weil J J,Honda H.Effects of Fin Geometry on Boiling Heat Transfer From Silicon Chips with Micro-pin-fins Immersed in FC-72[J].International Journal of Heat and Mass Transfer,2003,46(21):4059-4070
[3]Byon C,Kim S J.Critical Heat Flux of Bi-porous Sintered Copper Coatings in FC-72[J].International Journal of Heat and Mass Transfer,2013,65:655-661
[4]曾勇,徐宏,侯峰,等.火焰喷涂型表面多孔管的性能研究[J].化工机械,2010(2):141-144Zeng Y,Xu H,Hou F,et al.Property Studies on the Flame-Sprayed Type Surface Porous Tubes of a Multilayer Bound Vessel[J].Chemical Engineering&Machinery,2010(2):141-144
[5]Lee C Y,Bhuiya M Ml H,Kim K J.Pool Boiling Heat Transfer with Nano-Porous Surface[J].International Joumal of and Heat Mass Transfer,2010,53:4274-4279
[6]Betz Amy Rachel,Xu J,Qiu H H,Attinger D.Do Surfaces With Mixed Hydrophilic and Hydrophobic Areas Enhance Pool Boiling[J].Applied Physics Letters,2010,97(14):141909
[7]Hsu C C,St T W,Chen P H.Pool Boiling of Nanoparticle-Modified Surface with Interlaced Wettability[J].Nanoscale Research Letters,2012,7(1):1-7
[8]Karrsi S B R.Dynamics of Bubble Departure in MicroGravity[J].Chemical Engineering Communications,1988,70(1):127-135