TiN-导热油纳米流体辐射特性实验研究

通过实验研究了两步法制备的TiN-导热油纳米流体的辐射特性,测量了纳米流体的导热系数、常规透射率及半球透、反射率,还研究了质量分数以及光程对其透射率、反射率的影响。实验结果表明,质量分数为0.010%的TiN-导热油纳米流体对辐射能的吸收效果最好,吸收率为97%左右,且其导热系数大于基液的导热系数,可以在一定程度上提升太阳能集热器的集热效率。因此,其在太阳能的高效利用方面具有较好的潜力。

油基CuO纳米流体的制备及热稳定性实验研究

选用改进后的"两步法"制备Cu O/导热油纳米流体,并通过实验得到最佳分散剂为油酸、最佳油酸量为1m L/0.3 g Cu O、最佳超声振动时间为1.5 h。对于该纳米流体在中温(80~150℃)下的热稳定性进行试验探究,结果表明温度的升高、加热次数和时间的增加都会加剧纳米流体的团聚。随后提出了四点改进措施,并设计了正交试验验证,得到了各因素的影响程度主次以及提高纳米流体热稳定性的最佳措施。

Effects of TiO2 nanoparticles on thermal conductivity of heat transfer oil

There is a lack of thermophysical data of heat transfer oil and nano-oil in the high temperature range of 50-300 ℃ for designing and developing heat transfer oil furnace and its heating systems. In the present study, the thermal conductivity values of heat transfer oil and TiO2 nano-oil in the above high temperature range were measured by a newly developed high-temperature thermal conductivity meter. Based on the principle of least square method, the thermal conductivity values obtained from experiments were fitted separately, and the correlation between thermal conductivity and temperature of heat transfer oil and TiO2 nano-oil was obtained. The results show that the thermal conductivity and the increased percentage of thermal conductivity of TiO2 nano-oil are proportional to the increase of particle size and mass fraction of nanoparticles, but thermal conductivity is in reverse proportion to the increase of temperature and the increased percentage of thermal conductivity is less affected by temperature.