A Void Fraction Characterisation by Low Frequency Acoustic Velocity Measurements in Microbubble Clouds

Low frequency acoustic velocity measurements have been applied for the characterization of microbubble clouds generated in water. This method, based on the Wood's model (1941) links the acoustic velocity throughout a two-phase medium to its void fraction value. Low frequency means below resonance frequencies of the bubbles inside the cloud. An original bench was developed to allow the qualification of this method. The experiments conducted allowed us to characterize void fraction values between 10(-3) and 10(-7). The radii of the studied microbubbles are between a few micrometers and a hundred micrometers. (C) 2015 The Authors. Published by Elsevier B.V.