Experimental characterisation of the thermal behaviour of different materials submitted to ultrasound in an ultrasonic fountain.

The purpose of this study was to characterize the thermal behaviour of different materials subjected to an ultrasonic fountain created by an ultrasonic piezoelectric transducer. Tests were conducted with an infrared camera to determine the surface temperature of the material samples. The main conclusion is that the plastics when subjected to the ultrasonic fountain tend to heat up strongly and can reach temperatures up to 200 °C in few seconds. The temperature rise depends on the nature of the plastic material and the experimental conditions namely the height of liquid above the transducer and also the distance between the liquid surface and the sample. The comparison with an aluminium plate and a Pyrex plate gives a better understanding of the phenomenon that is related to three characteristics of the experiment: the transmission of the incident wave, the ability of the material to absorb this energy as heat and finally, the thermal and thermodynamic properties. These three parameters determine the behaviour of the plate when it is subjected to the ultrasonic fountain. In order to achieve a performing active control system, the choice of the material that faces an ultrasound fountain is very important to avoid any damage.