Alexdav
Flow in a vertical pipe section should be the same as in a horizontal pump section, especially with a pump pushing the fluid along.
As for the axial pump question, Cranes Technical Paper 410 (or 410M) "Flow of Fluids" contains a table which specifies the minimum flow rates and pipe diameters which will lead to a velocity of 2.5 m/s or greater. As far as I know, there is not anything which says that you can't have flow rates greater than 2.5 m/s; that is a fairly moderate flow rate. But the question might be, "Is your axial pump designed to pump that capacity?"
Can you provide a bit more information, like the size of the piping and any pump information you have? Or what your specific concern is?
Patricia Lougheed
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