MEASUREMENT OF VELOCITY-FIELDS INSIDE CORRUGATED CHANNELS BY A THERMOGRAPHIC METHOD

To characterize the hydrodynamic of flows in plane channels of small hydraulic diameter, it is necessary to measure the velocity field by a non intrusive method. The thermographic method we have developped consists in visualizing the propagation of the head of a heat step inside the channel. A numerical storage of the temperature maps allows to calculate, all over the channel, the time of passage of the heat step, and than to estimate the velocity field. The study of heat transfer, between the bulk flow and the outer wall, have guided us for sizing the experimental loop. This method have been applied to the study of velocity fields inside corrugated channels, used in plate heat exchangers.