Al2O3纳米流体沸腾传热临界热流密度影响因素研究进展

Research Progress on Influencing Factors of Critical Heat Flux in Boiling Heat Transfer of Al2O3 Nanofluids

随着电子设备热负荷的逐渐增加,纳米流体沸腾传热作为一种新型强化换热方式,受到越来越多的关注。本文主要综述了近年来关于纳米流体沸腾传热临界热流密度(CHF)的相关研究,并聚焦Al 2O 3纳米流体,归纳了各种因素对沸腾传热CHF的影响,分析了它们强化或弱化CHF的原因,得到了它们对CHF影响的一般规律。结果表明:纳米颗粒的添加可以有效提升CHF;随着纳米颗粒浓度的升高,CHF的变化存在增大、先增大后基本不变、先增大后降低等情形;微通道能够有效提升CHF,但通道尺寸较小时,CHF随尺寸的增大而增大;加热壁面越光滑CHF越低。此外,还概述了壁面倾斜角、壁面润湿性、工作压力以及外场(电场、磁场、重力场、超声波)等因素对CHF的影响。最后,指明了纳米流体沸腾传热CHF的发展方向并展望了其在机载环境下的应用前景。

With the sharp increase of heat loads of electronic equipment,boiling heat transfer of nanofluids,as a novel type heat transfer enhancement,receives more and more attentions.This paper mainly summarizes the related researches on critical heat flux(CHF)of boiling heat transfer of nanofluids in recent years,especially on Al 2O 3 nanofluids.The influences of various factors on CHF of boiling heat transfer are briefly summarized,the reasons why they strengthen or weaken CHF are analyzed,and the general rules of their influences on CHF are obtained.The results indicate that the addition of nanoparticles can effectively improve CHF.With the increase of nanoparticle concentration,CHF might increase,increase first and then remain unchanged,or increase first and then decrease.Using microchannels can effectively improve CHF,but CHF increases with the increase of channel size when the channel size is small.The smoother the heating wall is,the lower the CHF is.In addition,the influences of wall inclination angle,wall wettability,working pressure and external force fields(electric field,magnetic field,gravity field,ultrasonic wave)on CHF are also summarized.Finally,the development direction of boiling heat transfer CHF of nanofluids is pointed out and its application prospect in airborne environment is presented.