Measurement of Taylor bubble shape in square channel by microfocus X-ray computed tomography for investigation of mass transfer

- The dissolution of a CO2 Taylor bubble in a square milli-channel was investigated.
- Volumetric dissolution rates were measured utilizing X-ray radioscopy.
- The microfocus X-ray computed tomography was used for calibration.
- Ratios of Taylor bubble thin film region area to total surface area are reported.

This paper addresses the measurement of the dynamic evolution of Taylor bubble volume and interfacial area during mass transfer. Carbon dioxide (CO2) Taylor bubbles were placed in countercurrent water flow in a square channel. Microfocus X-ray radioscopy enabled the measurement of volumetric dissolution rates. The measurements were calibrated by microfocus X-ray computed tomography scans of non-dissolving air Taylor bubbles. The reconstruction algorithm was adapted to correct the slight position shift of the Taylor bubble during the tomographic scan. The obtained three-dimensional representation of the Taylor bubble's shape enabled the measurement of Taylor bubble's true volume and interfacial area, which were correlated to the two-dimensional radioscopic measurements. The volumetric dissolution rates were measured in a square milli-channel with hydraulic diameter of dh=6 mm. Furthermore, the thin film region of the constricted Taylor bubble's surface near the planar channel walls was extracted from the data and the ratio to the total Taylor bubble surface was computed.

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