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 Jason_Duguay September 18, 2018 21:33

Air rising too quickly in water - twoPhaseEulerFoam

Hello everyone,

I am simulating the effects of air being injected into a rectangular tank with the twoPhaseEulerFoam solver. The main idea is to test if twoPhaseEulerFoam can accurately predict the recirculatory flow that occurs adjacent to the rising bubble plume.

The air enters through the top of a porous stone positioned on the floor of the tank near the wall. Air is injected with a fixed value of (0 0 0.0635) m/s to provide the correct flow rate of 9.6 l/min. The injection surface is 0.035 x 0.07 m = 0.00245 m^2.

I measured the rise velocity of the bubbles to be approximately 0.33 m/s from high-speed video I took of the experimental validation study.

My problem is that U.air is rising at nearly 0.6 to 0.7 m/s. I have tried a number of drag coefficient models, swarm corrections, turbulent dispersion, etc. but nothing seems to be able to get the rise velocities in the reasonable range of 0.3 to 0.4 m/s.

If anybody could provide some insight, it would be hugely appreciated.

Here is a link to a few images of the simulation to give you an idea of what I am struggling with:

https://www.dropbox.com/sh/7e4bk6o3v...psowrvH5a?dl=0