论文部分内容阅读
本文通过实验方法测量了H_2O+SiO_2纳米流体在剪切流场(剪切速率范围在89~820 s~(-1))中的等效热导率,并与已有的关联式进行了比较.测量结果表明纳米流体的热导率随着剪切速率的增加而增加,并且当剪切速率达到一个临界值时热导率会出现最大值.颗粒体积分数和颗粒直径越大,纳米流体热导率随着剪切速率的增加越明显.通过与关联式的比较发现,已有关联式几乎不能预测纳米流体等效热导率的增加,同时关联式中热导率会随着剪切速率的增加而一直增加,这与实验结果不符。
In this paper, the equivalent thermal conductivity of H_2O + SiO_2 nanofluids in the shear flow field (shear rate range 89 ~ 820 s ~ (-1)) has been measured experimentally and compared with the existing correlations The results show that the thermal conductivity of nanofluids increases with the increase of the shear rate and the maximum value of thermal conductivity occurs when the shear rate reaches a critical value.The larger the volume fraction of particles and the diameter of the particles, Conductivity increases with the increase of shear rate.Compared with the correlation, it is found that there is almost no correlation between the equivalent thermal conductivity of the nanofluids and the thermal conductivity of the associated fluid will decrease with the shear rate Increase has been increasing, which is not consistent with the experimental results.