I have a question concerning simultaneous sampling of water and gas phase.
The situation is a pipe (diameter somewhat around 15 cm) where a mixture of water and gas is flowing through (two-phase flow). Assuming that the flow is separated and the gas phase is moving on top, what will happen if I open a sampling tap at the bottom of the pipe? The flow is induced by a pump and the pressure in the system is above ambient (20 bar).
My assumption is, that I only sample the water and the gas phase on top will not leave the pipe unless I allow the gas phase to "connect" with the tap by extracting a big amount of fluid.
The problem is maybe comparable to a bottle of sparkling water, where I drill a small hole at the bottom. Will I only sample the fluid phase or will I sample a mixture of both?
I hope somebody has an answer. Thanks in advance!