An experimental study of heat transfer and pressure drop characteristics of multi-wall carbon nanotubes suspensions in coaxial heat exchanger
Résumé
The thermal performances of water-based multi-wall carbon nanotubes suspensions are experimentally investigated in a coaxial heat exchanger. A test section consisting of a coaxial horizontal tube was designed and finely instrumented. The convective heat transfer characteristics with constant wall temperature are evaluated for four different multi-wall carbon nanotubes based nanofluids at 0.05% in weight concentration. The measurements of thermal conductivity and dynamic viscosity of the nanofluids with operating temperature were investigated experimentally. The effect of the aspect ratio of carbon nanotubes, the base fluid and the surfactant on viscosity, thermal conductivity and laminar convective heat transfer was studied. Based to the experimental results, it is shown that the enhancement of the thermal conductivity and the heat transfer increased with the aspect ratio and decreased when the thermal conductivity of the base fluid increases.