Experimental investigation on mid-temperature thermal stability of WO2.9-SiC binary nanofluid

Abstract

Binary nanofluid has excellent heat transfer performance and spectral selective absorption characteristic. However, when nanofluid is applied to actual systems, it is subject to severe thermal shock, which leads to quick agglomeration and therefore deterioration of the performances. This study aims to investigate the stability of tungsten oxide (WO2.9)-silicon carbide (SiC) binary nanofluid in actual service environment. The surface of nanoparticles was chemically modified by the coupling agent method, and the process was optimized. Then, the binary nanofluid was prepared with the optimal process of unitary nanofluid and the improved two-step method. And the actual working condition was simulated by interval heating as well as magnetic stirring. Finally, the preparation process was optimized further from the aspects of particle size, particle concentration, and thermal shock temperature. The results show that the binary nanofluid prepared by the optimum preparation process can maintain great stability after cyclic thermal shock experiment at 90 ℃ for 14 days, which put a foundation for the application of binary nanoparticles into solar beam splitting and enhance its practicality.