Abstract: Heat transfer performance of nanofluids in nucleate pool boiling was experimentally investigated in 6 mm copper beads. The nanofluid was prepared by dispersing the 40nm CuO nanoparticles in the base fluid water by using sodium dodecyl benzene sulphate(SDBS) as the surfactants,and both the proportion of the mass fraction were different. Experimental results showed that the nanofluid is in stability and has a good heat transfer performance at the same concentration ranges from 0.01% to 0.03% of nanoparticles and surfactants. The nanofluid could transfer heat more effectively at the slightly higher concentration of surfactants. The best heat transfer coefficient from the range above was 41670 W/(m²·K),where the concentration of CuO and SDBS were 0.02% and 0.03%,respectively. The sedimentation occurred obviously at the larger proportion of nanoparticles,which could enhance or weaken the boiling heat transfer at the different grade. The visualization research of nanofluid pool boiling was also investigated. It could interpret experimental results by analyzing the detachment characteristics of boiling bubble. All these results in this paper can be supplied for the research of nanofluid pool boiling on porous bead-packed structures with useful experimental data.

Key words: nanofluid, surfactants, pool boiling, porous media, heat transfer

摘要： 对CuO-水纳米流体在6mm多孔球层内进行池沸腾实验研究。实验使用了40nm的CuO纳米颗粒，加以不同浓度的十二烷基苯磺酸钠（SDBS）作为表面活性剂，配成多种不同配比关系的纳米流体。实验结果表明，当表面活性剂浓度与纳米颗粒浓度在0.01%~0.03%（质量分数，下同）之间变化时，两者浓度相近的纳米流体稳定性较好，沸腾传热效果高。其中表面活性剂浓度略高于CuO浓度时，传热效果较好，在SDBS浓度为0.03%、CuO浓度为0.02%时达到最大，为41670W/(m²·K)；而纳米颗粒浓度增大时，根据其对纳米流体的稳定性和沉降效应的影响，在不同程度上可增强或削弱沸腾传热。同时对纳米流体的池沸腾进行可视化研究，利用气泡脱离特性对实验结果作了诠释。所得结果可为纳米流体在多孔球层的池沸腾传热特性研究提供有益的研究数据。

关键词: 纳米流体, 表面活性剂, 池沸腾, 多孔介质, 传热