TIME RESPONSE MODELING OF AN ULTRASONIC THERMOELECTRIC PROBE

A thermoelectric probe has been developed in our laboratory. It consis ts of a thermocouple embedded in an absorbing material, such as silico ne. Its response allows us to measure the ultrasonic intensity reparti tion in the reactor either by means of the initial rate of temperature (dT/dt)(0) or by the difference between the equilibrium temperature T -eq and the temperature of the medium T-0 (Delta T = T-eq - T-0). It i s shown that the increase of temperature of the absorbing material is linked to the absorption of ultrasound transmitted in the medium. A he at conduction model allows us to interpret the results, the convective transfer being negligible. It is found that the ultrasound propagatio n surprisingly seems to be sensitive to the flow regime.