Local liquid velocity measurements in air-water bubbly flow

Liquid re-circulation in turbulent vertical pipe flow behind a cylindrical bluff body and a ventilated cavity attached to a sparger

“…Following Sun et al (2002) who combined Eqs. (5) and (6) to eliminate ϑ a and ϑ w , and using the values of the refractive index given above, the following coordinate correction was obtained and applied in the present experiment: The superficial liquid velocity (ū = 4Q L / D 2 ) wasū = 0.577 m s −1 for most of the measurements.…”

“…There are various papers in the literature concerning LDV measurements in two-phase flow and a comprehensive summary of the several signal discrimination approaches are given by Sheng and Irons (1991). In this study we follow the method suggested by Sun et al (2002). They found that for an average gas void fraction of less than 8.5%, the bursts of the seeding particles could be well separated from those of the bubbles without any further signal discrimination by using enough seeding particles (the ratio of the seeding particle number concentration to the bubble number density was of the order of 100), high laser power to increase the beam intensity scattered by the seeding particles and a high Photomultiplier tube (PMT) voltage (around 1150 V) so they could detect the light scattered by the seeding particles.…”

Shock wave in a bubble flow with high gas content

“…Second, the film sensor has a quartz coating which prevents the formation of bubbles on its surface due to heating [6]. Third, the film sensor is recomended to make measurements in two-phase flows in a number of papers [7][8][9][10][11][12][13][14][15][16][17][18][19][20]. Fourth, the substrate heating losses of the film sensor in water can be neglected [11].…”

“…King's law [21] is used in our work as a law connecting the flow rate with the energy spent on heating the film. Using [7][8][9][10][11][12][13][14][15][16][17][18][19][20]22], King's law for a supersonic microbubble-fluid flow is written as…”