2 phase flow validation on this case.
 

Hello Everyone,

This is one of Master of Science student who's trying to evaluate the experimental results, with self-developed fluent based multiphase modeling approach.

I did finish the computational analysis successfully, for a large number of cases, a number of data points discussed further:
3 Test sections of sudden expansion, and 3 test section of sudden contraction
the values are: inlet 0.375,0.315,0.19 inches and outlet 0.5 for contraction and vice versa. This study is Two-phase flow in the area of sudden expansion and contraction channels.
Model, Gas-liquid Two-phase flow Eulerian-Eulerian Multiphase model, with RSM model (linear pressure strain gauge).
I would like to have the second opinion(Validation) on following points, since there are some people who are quite experts in CFD field, with yrs of industrial experience.

1. The pressure drop value based on computational analysis is lesser than experimental value for a channel with larger diameter ratio(Ex.: inlet 0.375, outlet:0.5 inches) as well as lower mass flow rate or lower superficial velocity. while for the channel with a diameter smaller area ratio (Ex.: inlet 0.14, outlet:0.5 inches) as well as higher flow rates shows accurate agreement with experimental results. Is it true?

2. Volume fraction based on second phase flow option under the multiphase tab, changes the smoothness and shape of pressure profile, while it does not contribute to pressure drop in two-phase flow, is it true?

3. Volume fraction and void fraction, both are different things in FLUENT. Is it true?

Kindly Help me in this, please

Thank you,

Have a nice day.