摘要
将平均粒径为30nm和50nm的SiO2纳米颗粒添加到EG（乙二醇）的基液中制成SiO2-EG纳米流体,利用粒度分析法、吸光度分析法和Zeta电位分析法分析其悬浮稳定性,当超声时间为3h时,其分散性和稳定性最好。对SiO2-EG纳米流体的热物性能参数如黏度、表面张力、导热系数,在不同体积分数、粒度和温度条件下进行测试分析表明,SiO2-EG纳米流体的黏度高于基液的黏度,表面张力低于基液的表面张力,导热系数高于基液的导热系数。在常温下,体积分数为0.5%时,30nm和50nm两种粒径的SiO2-EG纳米流体的粘度比EG粘度分别提高了15.41%和13.17%,表面张力系数比EG分别降低了3.23%和2.54%,导热系数分别提高38.36%和31.47%。进一步研究发现温度的升高导致SiO2-EG纳米流体的粘度和表面张力系数均有所降低,而导热系数却增加。
SiO2 nanoparticles with average diameters of 30nm and 50nm were added into ethylene glycol to prepare SiO2-EG nnanofluids. The analysis of particle size, sorbancy, and zeta potential indicate that the uniformly and stably disperse SiO2 nanoparticles in Ethylene glycol can be obtained by 3 hours of ultrasonic vibration. The properties of SiO2-EG nanofluids such as viscosity, surface tension coefficient and thermal conductivity were investigated under the conditions of various concentrations, particle size and temperatures. The results show that comparing with the liquid-based, the viscosity and thermal conductivity increase for SiO2-EG, and the surface tension decreases. , the viscosity of SiO2-EG nanofluids with 30nm and 50nm particle size for approximately 0.5vol.% are improved by 15.41% and 13.17% at the room temperature, respectively. the corresponding surface tension values decrease 3.23% and 2.54%, the thermal conductivities was enhanced by 38.36% and 31.47%. Furthermore, the viscosity and surface tension coefficient of the SiO2-EG nanofluids have a tendency to decrease with increasing temperature, but the thermal conductivities follow an increased trend.
基金
山东省自然科学基金项目（Y2007F28）
济南市高校院所自主创新计划项目（200906048）
