Paper presented at the 5th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 1-4 July, 2007.
This keynote lecture aims to determine the heat transfer
enhancement in natural and in mixed convection between a
vertical wall, heated by Joule effect, and air in the presence of
small air pulsating aspirated and expired jets, in conditions of
medium and large temperature differences between wall and
air, namely from 25 to 70K. Experimental measurements have
been taken both with and without pulsating and continuous
expired and aspirated jets. The expired jets blow out
perpendicularly from the wall surface. A thermo camera was
used to ensure the wall temperature uniformity. A hot wire
anemometer and visualization with smoke were used to found
information about the air velocity field. The parameters which
maximize the convective heat exchange have been computed.
The present research represents a first step of a basic study
to optimize the turbine behavior cooled by pulsating jets.