Abstract
Presence of interface in gas-liquid two-phase flow makes it difficult to measure liquid velocity using LDV at a high void fraction. In the present study, we have developed small LDV optics to avoid the difficulty in optical access by submerging the LDV probe into a flow field. The diameter of the probe is 7 mm. The developed system is applied to bubbly flow in a bubble column to examine its applicability to bubbly flow at a high void fraction. Comparisons with a conventional LDV system show that the accuracy and reliability of the developed system are the same level as the conventional system, and that the developed system can measure liquid velocity in bubbly flow at high void fractions, in which the conventional LDV cannot measure the liquid velocity. The measured data show that the axial mean velocity and turbulence intensity increase with the gas volumetric flux J_G not only at low JG but also at high J_G.
