Pool boiling of Nanofluids on flat heaters

Water-based γ-Aumina and Carbon nanotubes nanofluids have been examined for pool boiling heat transfer in atmospheric pressure on horizontal flat heaters. The particle concentrations were 0.1wt% and 0.01wt%. All nanofluids were stable and set to pH7 before boiling. Depending on surface roughness, the copper heaters were categorised as smooth or rough. Nanoparticles were spherical or acicular shapes. Boiling heat fluxes were varied up to 189kW/m2. Nanoparticles were of three different shapes, and the nanofluids were in three concentrations. It has been found that dilute nanofluids are capable of enhancing BHT. Particle deposition occurs on the heater which increases with concentration. Moreover, dense nanofluids introduce thermal instability to the system. The importance of the ability of a nanofluid to withstand boiling temperature is also highlighted.