Coherent sound field generated by an airborne power ... · Coherent sound field generated by an...
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Coherent sound field generated by an airborne power
ultrasonic transducer with rectangular plate radiator for food
dehydration purposes.
Introduction: The use of airborne power ultrasonic transducers (APUT) for food dehydration processes may carry important advantages
regarding energy consumption, processing time and quality of the final product. The high intensity acoustic field generated by the
transducer, and propagated along the processing chamber provokes the desired effects in the samples located strategically in some
points of the near field. Therefore, the main goal when designing an ultrasonic technology is that the system generates a coherent
acoustic field in free field with a directive behavior.
The ultrasonic system considered for this purpose consists of an APUT with rectangular plate radiator working at a flexural mode with
twelve nodal lines (12NL) around 21 kHz, and a set of reflectors to put in phase the ultrasonic waves in order the generate the required
coherent field.
This work presents the acoustical effects provoked by the set of reflectors in terms of ultrasonic field and directivity, obtained by
experimental methods.
Conclusion: This work has proved that the use of a
reflectors system enables the generation of a directive
ultrasonic field with higher acoustic pressure because
the energy of both faces of the radiator is used in a
coherent field, obtaining a most efficient system for food
dehydration processes.
X=38 mm X=1129 mm X=38 mm X=1083 mm X=2612 mm
Acknowledgments: This work has been
supported by the project DPI2012-37466-
C03-01 funded by the Spanish Ministry of
Economy and Competitiveness.
Directivity
Ultrasonic field
Roque R. Andrés, Enrique Riera, Ángel Guinot, Ignacio Martínez, Alberto Pinto
Dpto. Sensores y Sistemas Ultrasónicos, ITEFI, CSIC, Serrano 144, E28006-Madrid, Spain
APUT
12 NL operational mode Ultrasonic system with reflectors
Reflectors
Rectangular radiator
Horizontal (XY) plane
Vertical (XZ) plane
YZ slice. X=38 mm YZ slice. X=1129 mm YZ slice. X=0 mm YZ slice. X=1083 mm YZ slice. X=2612 mm
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