Session: 5.2.2 - Novel Measurement Techniques in Fluid Engineering II

Paper Number: 170339

170339 - Acoustic Bubble Spectrometer: Noninvasive Real-Time Measurement of Bubbles in Complex Systems 

Abstract: 

Measurement of bubble size distribution and void fraction is of vital importance in many multiphase flow applications. This contribution describes an acoustics based device, the ABS Acoustic Bubble Spectrometer®, which can conduct measurements accurately in near real-time in a cost-effective fashion. By propagating short bursts of sound at different frequencies through bubbly medium, it measures frequency dependent attenuations and phase velocities of the acoustic waves and uses them to obtain the bubble size distribution (number of bubbles per size) by solving an inverse problem.
This presentation will summarize prior validation studies,  where ABS results are compared agains visual measurments using a high-speed micro-video system to take videos of the bubbles at the same time and within the test volume interrogated by the ABS system. Then both the acoustic data and the video frames are then analyzed and compared using many datasets under the same conditions.  
Recent developments, both in hardware and software, as well as their extention into measuring voids in structure will be showcased. Particularly, degradation of in-service concrete infrastructure has proven to be a large public expense, estimated in the billions of dollars annually in the US. Recently, ABS ACOUSTIC BUBBLE SPECTROMETER® has been adapted for the task of assessing air void system quality in fresh concrete. Using acoustic transducers submerged in the fresh concrete, the ABS technology provides information on the quantity and size range of detected bubbles as well as some quantities of interest from the well-known ASTM C457 test in less than one minute, including sample collection.

Presenting Author: Jingsen Ma Dynaflow, Inc.

Presenting Author Biography: