MEASUREMENT OF VELOCITY-FIELDS INSIDE COR RUGATED CHANNELS BY A THERMOGRAPHIC METHOD

To characterize the hydrodynamic of flows in plane channels of small h ydraulic diameter, it is necessary to measure the velocity field by a non intrusive method. The thermographic method we have developped cons ists in visualizing the propagation of the head of a heat step inside the channel. A numerical storage of the temperature maps allows to cal culate, all over the channel, the time of passage of the heat step, an d than to estimate the velocity field. The study of heat transfer, bet ween the bulk flow and the outer wall, have guided us for sizing the e xperimental loop. This method have been applied to the study of veloci ty fields inside corrugated channels, used in plate heat exchangers.