Simultaneous measurement of size and velocity of microbubbles moving in an opaque tube using an X-ray particle tracking velocimetry technique
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An X-ray particle tracking velocimetry (PTV) technique was developed to simultaneously measure the sizes and velocities of microbubbles in a fluid without optical aberration. This technique is based on a combination of in-line X-ray holography and PTV. The X-ray PTV technique uses a configuration similar to that of conventional optical imaging techniques, and is easy to implement. In the present work, microbubbles generated from a fine wire by electrical heating were used as tracer particles. The X-ray PTV technique simultaneously recorded size and velocity data for microbubbles (φ b =10–60 μm) moving upward in an opaque tube (inner diameter φ=2.7 mm). Due to the different refractive indices of water and air, phase contrast X-ray images clearly show the exact size and shape of overlapped microbubbles. In all of the working fluids tested (deionised water and 0.01 M and 0.10 M NaCl solutions), the measured terminal velocity of the microbubbles rising through the solution was proportional to the square of the bubble diameter. The proposed technique can be used to extract useful information on the behaviour of various bio/microscale fluid flows that are not amenable to analysis using conventional methods.
KeywordsX-ray PTV Microbubble Opaque material Size In-line holography
Experiments using the 1B2 beam line of the Pohang Accelerator Laboratory were supported in part by the Ministry of Science and Technology and POSTECH. The authors would like to thank the Korea Science and Engineering Foundation for financial support (grant no. R01-2004-020-10500-0) and Dr. H.S. Youn for his assistance during the experiments.
- Adrian RJ (1991) Particle-imaging techniques for experimental fluid mechanics. Annu Rev Fluid Mech 23:261–304Google Scholar
- Baek SJ, Lee SJ (1996) A new two-frame particle tracking algorithm using match probability. Exp Fluids 22:23–32Google Scholar
- Clift R, Grace JR, Webber ME (1978) Bubbles, drops, and particles. Academic Press, New YorkGoogle Scholar
- Dodge LG (1984) Calibration of the Malvern particle sizer. Appl Opt 23:2415Google Scholar
- Frumkin A, Levich VG (1947) On surfactants and interfacial motion. Zh Fiz Khim (Russian J Phys Chem) 21:1183–1204Google Scholar
- Leavers VF (1992) Shape detection in computer vision using the Hough transform. Springer, LondonGoogle Scholar
- Levich VG (1962) Physicochemical hydrodynamics. Prentice-Hall, New YorkGoogle Scholar
- Moore R (1999) Optimal edge-based shape detection. Mathematics Department, Macquarie University, Sydney, AustraliaGoogle Scholar