An Experimental Analysis of Acoustic Drying of Carrots: Evaluation of Heat Transfer Coefficients in Different Drying Conditions

Abstract The aim of the present work was to ascertain the effect of ultrasonic waves on convective drying performance. In the tested range of process and operating conditions, it was proved that compared to a traditional convective process, ultrasounds enhanced the drying rate of cylindrical carrot samples. The obtained results suggested that ultrasound waves actually affected the external resistance to heat and mass transfer, thus improving the drying process mainly during the constant rate period. The heat transfer coefficient was estimated as a function of both air velocity and food diameter, thus allowing a quantitative comparison between traditional and acoustic-assisted convective drying. Keywords: Convective dryingFoodTransport phenomenaUltrasound ACKNOWLEDGMENTS Maria Aversa expresses special thanks to Tarcisio Zordan (Sintec S.r.l., Padua, Italy) for supplying the ultrasounds generator, transducer, and application system.