Investigation On The Preparation Of Gold Nanofluid And Its Photo Thermal Conversion Characteristics

Solar radiation is the main source of energy in the earth, improving its utilization efficiency can effectively relieve the energy issue. Photo-quantum conversion and photo-thermal conversion are the two absorption and utilization ways of solar energy. To improve the conversion efficiency, light absorption has to be enhanced, which is the primary step in the solar conversion. The absorption and conversion of working fluid can be enhanced by adding nanoparticle in the base fluid. Au nanoparticle serves as one of the most important metals in the application of plasmon resonance due to its high electrical conductivity and thermal conductivity, good stability and strong plasmon resonance in the wide wavelength range. And its photo-thermal conversion characteristics can be applied in thermal control, biological medicine, laser technology, induction technology and quantum computer.Au nanofluid was taken as the main object of this study and investigate the photo thermal conversion characteristics of Au nanofluid in the direct absorption solar collector with experimental method and numerical simulation. The main contests are listed as follows:A seed growth method was used to study the controllable preparation of Au nanoparticles. The effects of the reaction conditions such as the seed solution, the growth solution and the number of times on the synthesis of Au nanoparticles were studied. The growth law of Au nanoparticles was discussed based on the correlation theory of chemical reaction kinetics.For the stability of Au nanofluid, the effects of the volume fraction, temperature and time on the stability of Au nanofluid are considered considering the application of photo thermal conversion. The research method is mainly used to monitor the change of the concentration of Au nanoparticles by using UV visible spectrophotometer to evaluate the stability of Au nanofluid.The photo-thermal conversion performance was tested by photo-thermal conversion experiment device. The effects of nanoparticle size, material and other factors on the solar collector are investigated. The effects of the above parameters on the photo-thermal conversion efficiency and collector efficiency are discussed, and the characteristics and rules of the photo-thermal conversion of Au nanofluid in the direct absorption solar collector are obtained.Finally, based on the Rayleigh scattering approximation, the radiative transfer equation and energy conservation equation, a numerical method is used to study the photo-thermal conversion characteristics of one dimensional direct absorption solar collector. The effects of the particle material, concentration, size, solar intensity and the collector parameter on the collector efficiency are studied.