Evaluation of micro-bubble size and gas hold-up in two-phase gas-liquid columns via scattered light measurements

Mustafa M. Aslan, Czarena Crofcheck, Daniel Tao, M. Pinar Mengüç

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


In this paper, potential use of an elliptically polarized light scattering (EPLS) method to monitor both bubble size and gas hold-up in a bubble-laden medium is explored. It is shown that with the use of the new EPLS system, normalized scattering matrix elements ( Mij's) measured at different side and back-scattering angles can be used to obtain the desired correlations between the bubble sizes and input flow parameters for a gas-liquid (GL) column, including gas flow rate and surfactant concentrations. The bubble size distributions were first evaluated experimentally using a digital image processing system for different gas flows and surfactant concentrations. These images showed that the bubbles were not necessarily spherical. We investigated the possibility of modeling the bubbles as effective spheres. The scattering matrix elements were calculated using the Lorenz-Mie theory and the results were compared against the experimentally determined values. It was observed that the change in the bubble size yields significant changes in M11, M33, M44, and M34 profiles. An optimum single measurement angle of θ = 120{ring operator} was determined for a gas velocity range of 0.04-0.35 cm/s ( ID = 4.5 cm). The choice of the optimum angle depends on frit pore size, column diameter, gas pressure, and surfactant concentration. These results suggest that a simplified version of the present EPLS system can effectively be used as a two-phase flow sensor to monitor bubble size and liquid hold-up in industrial systems.

Original languageEnglish
Pages (from-to)527-539
Number of pages13
JournalJournal of Quantitative Spectroscopy and Radiative Transfer
Issue number3
StatePublished - Oct 2006

Bibliographical note

Funding Information:
This work is partially sponsored by the Center for Advanced Separation Technologies, US Department of Energy (DE-FC26-01NT41091). The authors wish to thank Dr. Rodolphe Vaillon for valuable discussions and Janakiraman Swamy for his help with data analysis.


  • Bubble size
  • Bubbles
  • Flow rate
  • Light scattering
  • Scattering matrix
  • Two-phase flow

ASJC Scopus subject areas

  • Radiation
  • Atomic and Molecular Physics, and Optics
  • Spectroscopy


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