Abstract
Nanofluid forced convection cooling and heating in a channel for hydrodynamically and thermally fully developed flow under constant heat flux was investigated analytically. Exact solutions show that the distributions of particles volume fraction, velocity and temperature for the case of heating differ substantially from those for the case of cooling. This non-similar heat transfer characteristics have been captured for the first time. Furthermore, a theoretical answer to the controversial issue on the anomalous heat transfer in nanofluids has been provided in this study. Only the solutions for the case of cooling suggest the anomalous heat transfer, in which the heat transfer rate exceeds the level expected from the increase in the effective thermal conductivity of nanofluids.
