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Kai Yan November 4, 2008 08:26

The lift force coefficient in bubbly flow
 
Lift force coeficient is important tor modeling bubbly flow. In paper "Phase Distribution Measurements during Transient Bubbly Two-Phase Flow in a Vertical Pipe" (Chem.Eng.Technol.23(2000)4), the lift force coeficient is 0.05 for air/water applications. Many other papers give the value of the coefficient as 0.1 for most practical air/water applications, when the results of modeling are fit to experiment datas. With the formulation of Tomiyama(2002), the lift force coeficient is calculated as about 0.3. So I have a little doubt on the the formulation of Tomiyama(2002).

I don't know which is right. I am modeling the bubbly flow of air/oil application.

Would you give some advices on the calculation of the lift force coeficient?

Thanks!

cc November 4, 2008 14:54

Re: The lift force coefficient in bubbly flow
 
There is no universal value of the lift coefficient. The reason is quite simple - it is not a constant as it depends on the bubble size, shape, volume fraction, etc. In addition, it is not always easy to separate lift effects from influences of other forces. If you look at the literature you may encounter anything from -0.1 (yes, negative!) to 0.5. The best bet would be to look for some experimental work with flow conditions similar to yours and take value from there.

Good luck.


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