[Maggakahn]

Hello everyone,

I am currently trying to validate my numerical model by comparing the pressure gradient obtained by the CFD model to semi-empirical equations derived by others. However, I am having trouble establishing the real pressure gradient.

I am investigating a vertical multiphase pipe flow (bubble flow regime), which is open to the atmosphare at the top and have some mass flow inlet for gas and liquid. I am currently using the VOF model to acheive this, but as there is pockets of gas throughout the pipe, the plotted pressure varies quite a lot.

I am also aware that the correct pressure gradient should not include the entrance length.

Any ideas on how to find the proper pressure gradient for this case?

I am greatful for any reply, thank you.
Regards,
Magnus