Airborne power ultrasound for drying process intensification at low temperatures: Use of a stepped-grooved plate transducer

Abstract

[EN] The recent development of a novel family of power ultrasonic transducers with extensiveradiating surfaces represents a step forward in the implementation of new airborne powerultrasonic (APU) technologies for drying process intensification at low temperature. Thesesystems have been successfully used to assist drying of different products at laboratorylevel. This work deals with the development, integration, and testing of a new APU trans-ducer with a stepped-grooved circular radiator as an initial step in scaling up the processand the results achieved in experiments of airborne atmospheric freeze-drying (AFD) ofapples. The results confirm that ultrasound application leads to a significant intensificationof the processes. The modeling shows that the increase of kinetic parameters was lowerthan those obtained with cylindrical transducers having the same electrical input. This factis attributed to the treatment of greater volume.