PREDICTION OF THERMO-PHYSICAL PROPERTIES OF SOLAR THERMIC FLUIDS DISPERSED WITH CARBON NANOTUBES USING ARTIFICIAL NEURAL NETWORKS

摘要

The aim of the paper is to investigate the effect of multi-walled carbon nanotubes on the thermo-physical properties of working fluids used in solar thermal engineering systems. Thermo-physical property evaluation is very essential to determine the efficiency and performance of solar thermal systems. Ethylene glycol and a commercially available thermic fluid therminol 62 are chosen as based fluids. Nanofluids are prepared by dispersing 0.1%, 0.25%, 0.5% and 0.1% weight fraction of surface modified multi-walled carbon nanotubes. The nanomaterials are surface modified before dispersion in the thermic fluids and extreme care is taken to prevent property deterioration during surface modification. Thermal conductivity of base fluids and nanofluids are evaluated in the temperature range of 100 to 225°C. Viscosity and density are evaluated in the temperature range of 50 to 150°C and extrapolated using standard methods. It is found that there is a 15 to 20% increase in the thermal conductivity with the dispersion of carbon nanotubes.