Study On Photothermal Conversion Performance Of Oil-Based Nanofluids

In comparing with water-based nanofluids, Oil-based nanofluids have more applicational value due to its high fluid temperature. Combined with ultrasonic stirring methods, we prepare different concentrations of carbon series(C60, graphite, carbon black) and a series of metal compounds(CuO, HgS) based on the transparent heat conducting oil. The radiation source such as xenon lamp and carbon dioxide laser are used. By using spectrophotometer, we observe absorption spectrum and measure their temperature change under different light irradiation. The photothermal conversion properties and absorption properties of different kinds of nanofluids are compared. Results show that fluids with nanoparticles added in can increase the absorption of light irradiation and show excellent photothermal conversion performance. In the certain concentration range, the rise of temperature of the nanofluids increases when concentration increases. But it reduce instead when the concentration continue to increase because of surface effect. The experimental data shows that the field range of optimal concentration ratio which can maximize photothermal conversion efficiency is 0.1mg/ml-0.2mg/ml. Analysis show that the improvement of conversion efficiency was major contributed by absorption effect and the scattering effect respectively for different nanofluids.Photothermal conversion experimental tests are also done about different nanofluids with the same concentration and mix nanoparticles of different types and different concentrations. Results show that different nanofluids have different ways to improve photothermal conversion efficiency and the two kinds of hybrid nanofluids will show better thermal properties than a single one.