纳米流体导热系数的影响因素分析

Analysis of Factors Affecting the Thermal Conductivity of Nanofluids

采用"两步法"制备质量分数为0.5%、1.0%、2.0%和4.0%的Cu-乙二醇纳米流体,添加了聚乙烯吡咯烷酮(PVP)和十二烷基苯磺酸钠(SDS)作为表明活性剂。利用Hot Disk 2500s热常数分析仪测试Cu-乙二醇纳米流体导热系数,在分析温度和颗粒浓度对其导热系数的影响基础上,重点研究了两种不同表面活性剂及添加量对纳米流体导热系数的影响。结果表明:Cu-乙二醇纳米流体的导热系数随质量分数的增大而增大,随温度的升高而增大。添加了PVP的纳米流体导热系数随PVP的添加量增加呈先增加后减小的趋势,但添加了SDS的纳米流体的导热系数小于无表明活性剂时纳米流体导热系数。适当的纳米颗粒浓度与PVP表面活性剂浓度比例,对提高Cu-乙二醇纳米流体的导热系数有帮助。

The Cu-ethylene glycol(EG)nanofluids with mass fraction of 0.5%,1.0%,2.0%and 4.0%were prepared by the"two step meth?od",and polyvinylpyrrolidone(PVP)and twelve alkylbenzene sulfonate(SDS)were added as the active agents.The thermal conductivity of Cu-EG nanofluid was tested by Hot Disk 2 500s thermal conductivity analyzer.Based on the analysis of the influence of temperature and parti?cle concentration on its thermal conductivity,the influence of two different surfactants and adding amount on thermal conductivity was mainly studied.The results show that the thermal conductivity of Cu-EG nanofluid increases with the increase of mass fraction,and increases with the increase of temperature.The thermal conductivity of nanofluids added with PVP increased with the increase of PVP,but then decreased.How?ever,the thermal conductivity of nanofluids added with SDS was less than that of nanofluids without indicating the thermal conductivity of the nanoparticles.The appropriate concentration of nano particles and the concentration of PVP surfactant can help to improve the thermal conduc?tivity of Cu-EG nanofluids.