Research on Thermophysical Properties of Nanoliquids Based on SiO_2 Nanoparticles for Use as a Heat-Transfer Medium in Solar-Thermal Converters

摘要

This paper presents an analysis of the modern state of studies of the thermophysical properties of nanofluids and the heat-transfer mechanism in them. The results of experimental studies of obtaining and determining the dynamic viscosity of the nanofluids (SiO~(2)+ water) with various concentrations of nanoparticles are given. Nanofluids are obtained using a two-stage method in an ultrasonic field with a frequency of 20 kHz. It is shown that, in the SiO~(2)+ water system, nanoparticles with sizes of 7, 12, and 16 nm are most stable. Various SiO~(2)concentrations in the volume range 0.5–5% were tested, and their thermophysical properties were studied for the purpose of using them as a heat-transfer medium in flat-plate solar collectors.