ISSN Print: 1049-0787
ISSN Online: 2375-0294
Indexed in
NANOFLUIDS FOR HEAT TRANSFER APPLICATIONS
ABSTRAKT
Nanofluids that are being investigated for heat transfer applications are liquids that contain a small volume fraction, up to perhaps 5%, of submicron particles. The presence of these nanoparticles has been shown to increase the static thermal conductivity of the base fluid by as much as 160% with the addition of carbon nanotubes. The viscosity of nanofluids, which will also be important for applications like heat exchangers, has also been studied, but to a much lesser extent compared with their thermal conductivity. A comprehensive theoretical description of the transport properties of nanofluids is still not available, but Brownian dynamics simulations suggest that for very small nanoparticles, less than about 30 nm, the increase in thermal conductivity is greater than the relative increase in viscosity. Only a few investigations have been conducted to date on convective and boiling heat transfer in nanofluids, and these revealed some conflicting results. Further measurements and analysis, some of which can be based on colloidal science, are required to optimize nanofluids for heat transfer applications.