Study On Radiation Characteristics Of Non-uniform Nanofluids

With the development of social economy,energy consumption is increasing year by year,and environmental pollution is becoming more and more serious.In order to save energy and protect the environment,the use of solar energy has gradually attracted worldwide attention.Because nanofluids have good spectral absorption,thermal conductivity and heat transfer performance,it is of great practical significance to be used as collectors of solar collectors.As for the radiation characteristics of nanofluids,scholars at home and abroad mainly focus on theoretical and experimental research.However,in practical problems,the stability of nanofluids will gradually weaken with the passage of time,and eventually the phenomenon of particle agglomeration and stratification will occur.In view of this phenomenon,the related simulation work has been done,and the radiation and heat transfer properties of nanofluids with gradient refractive index have been studied theoretically.In order to make nanofluids have better endothermic effect,the nanofluids were stratified by artificial regulation and related simulation calculations were carried out.By means of numerical simulation,one-dimensional flat plate model and two-dimensional square cavity model are established to simulate the radiation and heat transfer characteristics of nanofluids.The heat absorption effects of non-uniform Nanofluids and uniform nanofluids were compared and analyzed.The effects of different factors on the heat absorption of non-uniform nanofluids were considered,and the heat absorption optimization of different kinds of nanofluids was compared and analyzed.The results show that for the radiation characteristics of nanofluids,when SiO₂-H₂O nanofluids have gradient refractive index,their absorptivity increases obviously under uniform conditions,and the increase of refractive index gradient,mass fraction and particle size will enhance the absorption of solar radiation by nanofluids,to a certain extent,especially the effect of refractive index gradient and mass fraction is more obvious.For heat transfer characteristics,the addition of gradient refractive index also increases the temperature of nanofluids.Under non-uniform conditions,the average temperature of fluids increases with the increase of refractive index gradient,mass fraction and particle size,and the temperature of nanofluids also increases obviously after delamination.At the same time,the heat collecting effects of three nanofluids of SiO₂,TiO₂ and ZrC are compared and analyzed.The results show that ZrC has the strongest heat absorbing capacity and SiO₂ is the weakest.