title: Prediction of the acoustic and bubble fields in insonified freeze-drying vials.
abstract: The acoustic field and the location of cavitation bubble are computed in vials used for freeze-drying, insonified from the bottom by a vibrating plate. The calculations rely on a nonlinear model of sound propagation in a cavitating liquid [Louisnard, Ultrason. Sonochem., 19, (2012) 56-65]. Both the vibration amplitude and the liquid level in the vial are parametrically varied. For low liquid levels, a threshold amplitude is required to form a cavitation zone at the bottom of the vial. For increasing vibration amplitudes, the bubble field slightly thickens but remains at the vial bottom, and the acoustic field saturates, which cannot be captured by linear acoustics. On the other hand, increasing the liquid level may promote the formation of a secondary bubble structure near the glass wall, a few centimeters below the free liquid surface. These predictions suggest that rather complex acoustic fields and bubble structures can arise even in such small volumes. As the acoustic and bubble fields govern ice nucleation during the freezing step, the final crystal's size distribution in the frozen product may crucially depend on the liquid level in the vial.
authors: Centre RAPSODEE, UMR CNRS 5302, Université de Toulouse, Ecole des Mines d'Albi, 81013 Albi Cedex 09, France. Electronic address: louisnar@enstimac.fr.
authors: O
authors: O
authors: Louisnard
authors: Université Claude Bernard Lyon 1; LAGEP, UMR CNRS 5007, Campus de la Doua, Bt. CPE, 69616 Villeurbanne, France.
authors: C
authors: C
authors: Cogné
authors: Université Claude Bernard Lyon 1; LAGEP, UMR CNRS 5007, Campus de la Doua, Bt. CPE, 69616 Villeurbanne, France.
authors: S
authors: S
authors: Labouret
authors: Centre RAPSODEE, UMR CNRS 5302, Université de Toulouse, Ecole des Mines d'Albi, 81013 Albi Cedex 09, France.
authors: W
authors: W
authors: Montes-Quiroz
authors: Université Claude Bernard Lyon 1; LAGEP, UMR CNRS 5007, Campus de la Doua, Bt. CPE, 69616 Villeurbanne, France.
authors: R
authors: R
authors: Peczalski
authors: Centre RAPSODEE, UMR CNRS 5302, Université de Toulouse, Ecole des Mines d'Albi, 81013 Albi Cedex 09, France.
authors: F
authors: F
authors: Baillon
authors: Centre RAPSODEE, UMR CNRS 5302, Université de Toulouse, Ecole des Mines d'Albi, 81013 Albi Cedex 09, France.
authors: F
authors: F
authors: Espitalier
keywords: Acoustic cavitation; Bubble structures; Propagation in bubbly liquids; Sono-crystallization; Sono-freezing; Wave attenuation