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建立了测量纳米流体流动与对流换热性能的实验系统,探讨了不同pH值、分散剂浓度和纳米粒子质量分数对Cu-水纳米流体对流换热性能的影响。结果表明:pH值对Cu-水纳米流体对流换热系数的影响较小,这个现象启发了我们将纳米流体应用到未来工业中,可以不考虑pH值对纳米流体对流换热性能的影响。分散剂加入量是影响Cu-水纳米流体对流换热系数的重要因素,从分散稳定、导热系数和对流换热系数提高三个方面来考虑,在0.1%Cu-H2O纳米流体中,0.07%十二烷基苯磺酸钠被选为最优化浓度。另外,Cu-水纳米流体的对流换热系数随纳米粒子质量分数的增大而增大,但其对流换热系数的增加明显低于导热系数的增加。
The experimental system for measuring the flow and convection heat transfer of nanofluids was established. The effects of different pH, dispersant concentration and nanoparticle mass fraction on the convective heat transfer performance of Cu-water nanofluid were discussed. The results show that pH has little effect on the convective heat transfer coefficient of Cu-H2O nanofluids. This phenomenon has inspired us to apply nanofluids to future industries without considering the influence of pH on the convective heat transfer performance of nanofluid. The addition of dispersant is an important factor that affects the convective heat transfer coefficient of Cu-H2O nanofluids. Considering the dispersion stability, thermal conductivity and convection heat transfer coefficient, 0.1% Cu-H2O nanofluid, 0.07% Sodium dialkylbenzenesulfonate was chosen as the optimal concentration. In addition, the convective heat transfer coefficient of Cu-water nanofluids increases with the increase of the mass fraction of nano-particles, but the increase of convection heat transfer coefficient is obviously lower than the increase of thermal conductivity.