Event - Dept of Mechanical Engineering Graduate Studies

April 10, 2018 9:00 AM - 9:30 AM

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Transport of Bubbles and Oil Droplets in a Net Co-Flow Through a Rectangular Confinement

Speaker: Hirad Soltani
Seminar Chair: Dr. Lexuan Zhong
Supervisor: Dr. David Nobes
Date & Time: April 10, 2018, 9:00 am
Room: DICE 10-242


The passage of air bubbles and oil droplets with five net co-flow through a vertical straight rectangular flow channel is investigated experimentally and theoretically in this research. A flow channel, varying from 22 mm × 5.84 mm to 3 mm × 5.84 mm (width × thickness) cross-sectional geometry was used in the present experimental investigation. This flow channel allows the passage of bubbles and oil droplets from a region through two parallel plates into a confined rectangular region.

In the rising bubble experiments, the characteristics of bubbles varied from 0.75 mm to 3.2 mm diameter rising in a water/glycerol mixture were captured. A semi-empirical model for determining the bubble terminal velocity in a rectangular geometry is developed to predict this motion. The flow around air bubbles have been investigated using two image processing approaches of PIV and PTV. Because the PTV data were cluttered and hard to look at the velocity profile, the PTV sparse field was interpolated onto a regular gird. A theoretical model for streamlines in the flow surrounding bubbles has been developed to be compared against the experimental data.

Flow of an oil droplet in a net fluid co-flow through a vertical rectangular confinement is investigated in this study. Transparent canola oil was used as the oil droplet and glycerol was chosen to be the working fluid as it allowed the refractive index of both phases to be matched. Similar to rising bubble experiment, to quantify the velocity vector field, PIV and PTV processing approaches were employed to analyze the displacement of tracer particles in the oil droplet and surrounding fluid. An interesting observation was two counter-rotating vortices on either sides of the rising droplet, because of the mechanical force exerted on the droplet from the surrounding fluid and the confining walls.

Please Note: This seminar is part of a candidacy/ final defense examination. Please follow the instructions of the seminar chair at all times.