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We present a novel configuration to generate strong acoustic streaming vortices by a pinned oscillating membrane in a microchannel, its characterizations via advanced measurement techniques, and initial studies in application by augmentation of gas exchange across a permeable membrane towards microfluidic artificial lung technology. The configuration is stable over time and does not create any obstruction in flow passages. For an audible- frequency 20 Vpp input to a piezo buzzer, streaming velocity was measured up to 47 mm/s. Mixing from helical flow patterns in the microchannel augments gas transfer rate across the membrane up to 3.4 times compared to no actuation, allowing larger channel dimensions (better facilitation of scale-up manufacturing) and reduced shear (more hemocompatible) in microchannel-based artificial lung systems.
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3D Printed Helmholtz Microstreaming Structures: Analysis of Bubble Dynamics, Bulk Fluid Disturbance, and Resiliency in Nonquiescent Conditions
Microstreaming of acoustically excited bubbles presents great potential to mitigate fouling for membrane technologies. However, the acoustic streaming in bulk fluids under membrane separation conditions is not well explored. In this work, we investigate the microstreaming of 3D printed Helmholtz-like bubble-trapping structures (BTSs) under no flow, pressurized, and crossflow conditions that are relevant to membrane applications. Trapped bubbles are shown to generate formidable microstreaming that spans millimeter distances with velocity as high as 125 mm/s in a bulk aqueous medium. However, complex mode shapes of the bubble oscillation and bubble growth were observed during the frequency sweep. As a result, the streaming velocity decreases by 76% over 30 min, under single frequency excitation. The BTS displayed effective microstreaming under hydrostatic pressure up to 9.0 kPa, and under a crossflow velocity up to 0.2 mm/s, where the microstreaming zone reduced to <1 mm. The results provide the operation window, as well as challenges, for future integration of the BTS into bulk membrane separation processes.
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- Award ID(s):
- 2310937
- PAR ID:
- 10574547
- Publisher / Repository:
- ACS
- Date Published:
- Journal Name:
- ACS ES&T Water
- Volume:
- 4
- Issue:
- 4
- ISSN:
- 2690-0637
- Page Range / eLocation ID:
- 1741 to 1750
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
-
Accepted Manuscript
- Journal Article:
- https://doi.org/10.1021/acsestwater.3c00781
