Fundamental understanding of the interfacial behavior of molten salt based nanofluids on solid surfaces

The main issues of molten salts in concentrated solar power plants are their poor thermophysical properties and corrosion issues. To improve their properties nanoparticles are doped in molten salts. These suspended particles have an effect not only on the thermal, but also other properties such as viscosity and wettability, the latter having often been overlooked. In this work molten nitrate salts are doped with amorphous SiO\(_2\) and graphite particles. A series of contact angle measurements are conducted to study the effects of nanoparticle concentration, composition, particle geometry, temperature and surface type. A small fraction of nanoparticles leads to a shift of the transition from non-wetting to wetting at higher temperatures. Furthermore, wettability studies on different surfaces provide insights into the physiochemical mechanism of molten salt corrosion. Molecular Dynamics simulations of the nitrate salts-based silica nanofluids are also conducted. Novel interatomic parameters are calculated for the molten nitrate salts as well as the α-SiO\(_2\) and are used to predict the wetting behavior of the molten NaNO\(_3\) and KNO\(_3\) and their mixtures with and without a-SiO\(_2\) nanoparticles, in order to provide a better understanding of the wetting behavior of molten salt based nanofluids