底部封闭竖直细管内纳米流体的沸腾特性和临界热通量

吕伦春; 刘振华

底部封闭竖直细管内纳米流体的沸腾特性和临界热通量

上海交通大学机械与动力工程学院, 上海 200030

基金项目: 上海市科委基础研究重点项目资助(04JC14049)

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出版历程
- 收稿日期: 2006-05-17
- 修回日期: 2006-08-08
- 刊出日期: 2007-06-28

Critical heat flux of nano-fluids boiling in vertical small tubes with closed bottom

School of Mechanical and Power Engineering, Shanghai Jiaotong University, Shanghai 200030, China

摘要

摘要: 以水-氧化铜纳米颗粒组成的纳米流体为工质, 对底部封闭细小圆管内的沸腾特性以及临界热通量进行了实验研究.结果表明:沸腾时管内纳米流体的浓度不随加热时间长短而改变, 沸腾液体的纳米颗粒除微量吸附在管壁外, 其余全部被蒸汽携带走, 同时吸附层厚度到了一定程度就不再变化.相对于纯水而言, 随着纳米浓度的增加, 纳米流体的沸腾特性有所劣化, 这主要是因为纳米颗粒吸附在管壁上, 减小了壁面粗糙度, 从而减小了液体和壁面的接触角.随着纳米浓度的增加, 纳米流体的临界热通量也随之增加.纳米流体的临界热通量不仅与管长与管径比有关, 而且还与纳米浓度有关.
- 纳米流体 /
- 沸腾 /
- 临界热通量
Abstract: An experimental investigation has been performed to study the nucleate boiling characteristics and the critical heat flux(CHF) of water and water based CuO nanoparticle suspensions(nanofluids) in vertical small tubes with closed bottom.The experimental results indicated that the CHF and the particle concentration of the nanofluid in the tubes had hdlany change with the heating times in the boiling process.The boiling heat transfer of the nanofluids is somewhat poor compared with that of the base fluids,since the decrease of the active nucleate cavities results in the decrease of the solid-liquid contact angle on the heated surface with a very thin nanoparticle sorption layer.The boiling critical heat fluxes for the nanofluids increase significantly than that of the base fluids.An empirical correlation is proposed for predicting the CHF of nanofluids boiling in the vertical tubes with closed bottom.
- nanofluids /
- boiling /
- critical heat flux

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参考文献(14)

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