# Shadow imaging in bubbly gas–liquid two-phase flow in porous structures

Shadow imaging in bubbly gas–liquid two-phase flow in porous structures Shadow imaging is used for the investigation of bubbly gas–liquid two-phase flow in a porous structure. The porous structure is made of Somos $${^{\textregistered }}$$ ® WaterShed XC 11122, a clear epoxy resin used in rapid prototyping. Optical access is provided by using an aqueous solution of sodium iodide and zinc iodide having the same refractive index as the structure material ( $$n = 1.515$$ n = 1.515 ). Nitrogen is injected into the continuous phase at volumetric transport fractions in the range of $$\dot{\varepsilon } = 2.4-4.1\,\%$$ ε ˙ = 2.4 - 4.1 % resulting in a hold-up of $$\varepsilon = 0.94-2.17\,\%$$ ε = 0.94 - 2.17 % . The obtained images of overlapping bubble shadows are processed to measure the bubble dimensions. Therefore, a new processing sequence is developed to determine bubble dimensions from overlapping bubble shadows by ellipse fitting. The accuracy of the bubble detection and sizing routine is assessed processing synthetic images. It is shown that the developed technique is suitable for volumetric two-phase flow measurements. Important global quantities such as gas hold-up and total interfacial area can be measured with only one camera. Operation parameters for gas–liquid two-phase flows are determined to improve mass and heat transfer between the phases. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Experiments in Fluids Springer Journals

# Shadow imaging in bubbly gas–liquid two-phase flow in porous structures

, Volume 56 (9) – Sep 7, 2015
16 pages

Publisher
Springer Berlin Heidelberg
Subject
Engineering; Engineering Fluid Dynamics; Fluid- and Aerodynamics; Engineering Thermodynamics, Heat and Mass Transfer
ISSN
0723-4864
eISSN
1432-1114
D.O.I.
10.1007/s00348-015-2042-3
Publisher site
See Article on Publisher Site

### Abstract

Shadow imaging is used for the investigation of bubbly gas–liquid two-phase flow in a porous structure. The porous structure is made of Somos $${^{\textregistered }}$$ ® WaterShed XC 11122, a clear epoxy resin used in rapid prototyping. Optical access is provided by using an aqueous solution of sodium iodide and zinc iodide having the same refractive index as the structure material ( $$n = 1.515$$ n = 1.515 ). Nitrogen is injected into the continuous phase at volumetric transport fractions in the range of $$\dot{\varepsilon } = 2.4-4.1\,\%$$ ε ˙ = 2.4 - 4.1 % resulting in a hold-up of $$\varepsilon = 0.94-2.17\,\%$$ ε = 0.94 - 2.17 % . The obtained images of overlapping bubble shadows are processed to measure the bubble dimensions. Therefore, a new processing sequence is developed to determine bubble dimensions from overlapping bubble shadows by ellipse fitting. The accuracy of the bubble detection and sizing routine is assessed processing synthetic images. It is shown that the developed technique is suitable for volumetric two-phase flow measurements. Important global quantities such as gas hold-up and total interfacial area can be measured with only one camera. Operation parameters for gas–liquid two-phase flows are determined to improve mass and heat transfer between the phases.

### Journal

Experiments in FluidsSpringer Journals

Published: Sep 7, 2015

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