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采用两步法制配了Co-H_2O纳米流体,实验研究了纳米颗粒质量分数、直径、温度对纳米流体比热容的影响。结果表明:去离子水的比热随着纳米颗粒的添加不断减小,质量分数为0.1%和0.2%的Co-H_2O纳米流体比热比去离子水分别降低了2.88%和5.76%。随着温度的升高,纳米流体的比热容逐渐增大,并且纳米流体质量分数越大,其比热随温度变化的趋势相对低浓度的纳米流体越明显。粒径越小的纳米流体比热容越大。现有比热容计算模型与实验结果相差较大,不能直接用于计算。
Co-H_2O nanofluids were prepared by two-step method. The effects of the mass fraction of nanoparticles, diameter and temperature on the specific heat capacity of nanofluids were investigated experimentally. The results showed that the specific heat of deionized water decreased with the addition of nanoparticles, and the specific heats of Co-H_2O nanofluids with mass fraction of 0.1% and 0.2% were decreased by 2.88% and 5.76%, respectively, compared with deionized water. With the increase of temperature, the specific heat capacity of nanofluid gradually increases, and the larger the mass fraction of nanofluids, the more obvious the nanofluid with relatively low concentration of specific heat tends to change with temperature. The smaller the particle size of the nanofluid the greater the specific heat capacity. The existing heat capacity calculation model and the experimental results vary greatly, can not be directly used in the calculation.