Transport Phenomena in Thermal Engineering. Volume 2

ISBN Print: 1-56700-015-0

SIMULTANEOUS MEASUREMENT OF LIQUID AND BUBBLE VELOCITIES IN A CYLINDRICAL BATH SUBJECT TO CENTRIC BOTTOM GAS INJECTION

DOI: 10.1615/ISTP-VI.1050
pages 1429-1434

Résumé

A vertical bubbling jet was generated in a cylindrical bath by injecting air from a single-hole centric nozzle. The axial and radial velocity components of bubble and liquid in the vertical bubbling jet were measured simultaneously using an electro-resistivity probe and a two-dimensional laser Doppler velocimeter. The output signal of the LDV was processed on a personal computer at a sampling frequency of 2kHz. Hold signals were eliminated. Discrimination of the bubble and liquid velocities was made by referring to the output signal of the electro-resistivity probe. The accuracy of the present velocity measurement of bubbles and liquid was found to be satisfactory from a comparison with results obtained using an image processing technique for high-speed video pictures and a two-dimensional electro-resistivity probe.