Preparation And Photothermal Performance Of Boron Nitride Composite Nanofluid

With the development of heat storage technology,the liquid refrigerant requires heat transfer capacity is also increasing,therefore,a new type of heat transfer working fluid with small size,high thermal conductivity and good heat transfer is selected-nanofluid instead of traditional pure liquid working fluid has become a hot spot in current research.Since the metal oxide particles have the ability of light absorption and photothermal conversion,thus by selecting the appropriate nanoscale metal oxide particles,and gradually improve the full-wavelength absorption of sunlight,enhance the utilization of solar energy.However,generally due to the large specific surface energy of nanoparticles,there is a large van der Waals gravitational force between the particles,having disordered Brownian motion,which will cause the nanoparticles to gradually aggregate and settle.h-BN sheet-selected as the substrate supported metal oxide nanoparticles,subjecting them to the modification treatment of dopamine hydrothermal synthesis inspired by mussels,the particles are uniformly dispersed can not only solve the aggregation caused by particle size settlement problem,synergistic effect can improve the performance of the composite.The specific research content is as follows:Firstly,a series of h-BN/PDA/Zn O composite nanoparticles using different p H values were prepared by the hydrothermal synthesis of dopamine.The effects of different p H values on the morphology of the Zn O particles in the composite,and the stability of the water-based nanofluid,with the light absorption capacity and photothermal conversion efficiency in DASC.The results show that the p H value will affect the morphology of the Zn O particles.As the p H value continues to increase,the zinc oxide particles supported on sheet boron nitride change from borderless cross-linked to spherical shape to rod shape gradually.Through the test results of SEM and suspension stability,the p H=13 composite was selected to prepare the water-based nanofluid.Under the simulated sunlight source,the p H=13 compound was selected for the photothermal conversion test.The highest temperature of 0.05wt%nanocomposite fluid can reach 85.29?,which is 30.66?higher than pure water at most.Secondly,a series of h-BN/PDA/Fe₃O₄ composite nanoparticles with different mass ratios were prepared by dopamine solvothermal synthesis.Of different mass ratio of Fe₃O₄ nanospheres load on the sheet of boron nitride,the stability of water-based nanofluids,with the light absorption capacity and photothermal conversion efficiency in DASC.The results show that different mass ratios will not affect the size of Fe₃O₄ nanospheres,but within a suitable mass ratio range,comprehensive suspension stability test results,choose h-BN/Fe₃O₄ mass ratio 1:1 to water-based nanofluid.At the same time,loading Fe₃O₄ nanospheres on the h-BN sheet can make the composite nanofluids absorption band of sunlight more complete.Under the simulated sunlight source,the composite was selected for the photothermal conversion test.The highest temperature of 0.05wt%nanocomposite fluid can reach86.26?,which is 31.63?higher than pure water at most.Finally,we prepared a series of different molar ratios of h-BN/Cu O composite nanoparticles by hydrothermal synthesis.Of different molar feed ratio of copper oxide nano-particles in the load on the sheet of boron nitride and the stability of the h-BN/Cu O water-based nanofluid,with light absorbing ability and photothermal conversion efficiency in DASC.The results show that different molar ratios do not affect the size of Cu O nanoparticles and h-BN sheets,but within a suitable molar ratio range,there exists an optimum feed ratio:h-BN/Cu O 0.75:1(The suspension stability is the best in the basefluid).Simultaneously,loading Cu O nano-particles on h-BN sheet can make it more complete that the composite nanofluids absorption band of sunlight.Under the simulated sunlight source,the compound was selected for the photothermal conversion test.The highest temperature of 0.05wt%nanocomposite fluid can reach 92.21?,which is 37.58?higher than pure water at most.