三氧化二铝纳米流体粘滞度的实验研究

Investigation on the Viscosity of Al_2O_3 Nanofluids

使用直接混合法制备三氧化二铝纳米流体,探讨三氧化二铝纳米流体在不同浓度(0%,0.1%,0.5%,1.0%,ω)和温度(10～40℃)下粘滞度的变化规律.使用Brookfield DVIII+流变仪进行测量,发现添加入纳米粒子于去离子水中所得三氧化二铝纳米流体符合牛顿粘性定律,为牛顿流体.任一纳米流体的粘滞系数随着温度的上升而下降,呈反比关系,而随浓度上升而增加,呈正比关系,在温度40℃和浓度为1.0%(ω)时粘滞度增大比率可达到25.2%.而压降在任何浓度的纳米流体均与去离子水相差大约5MPa,显示加入纳米粒子对压降的影响不明显.当温度愈高时,压降也随着降低,代表未来可将纳米流体应用层面推向更高温的领域.

In this study,the Al2O3-water nanofluids produced from direct synthesis method were used as the experimental samples into three types of the mass fractions(0.1%,0.5%,1.0 %,ω).The objectives of this study were to discuss the dependence of viscosity of Al2O3-water nanofluids on the temperature(10～40℃) under the various mass fractions.These experiments used the rheometer(Brookfield DVIII+) to measure the stress force and stress ratio in the nanofluids of the various mass fractions and sample temperatures.The results show that the Al2O3 nanofluids conform to the Newtonian viscosity laws,they belong to the Newton's fluids.Viscosities of all nanofluids reduced with temperature increase,which was the reciprocal relationship;rose with concentration increase,which was the proportional relationship.At the temperature of 40℃ and concentration of 1.0%(ω),the growth rate of viscosity reached 25.2%.Pressure drops between all nanofluids with different concentrations and deionized water were about 5 MPa,and it showed that the effect of the pressure drop due to adding nanoparticle was not obvious.Pressure drop reduced with temperature increase,and it shows that the nanofluids will be applied in the field of high temperature.