velocity calculations in mass flow inlet boundary condition
 

hi
I have a problem with fluent.when I specified a mass flow inlet condition for nozzle inlet of a shell and tube heat excganger, fluent calculate another velocity value for this inlet than I evaluated with continuty eq.

Give more information... 2D or 3D is the problem and how you calculate velocity? if the problem is 3D make sure your density is correct and just apply
v=G/S, where
v-velocity [m/s]
G-mass flowrate [m3/s]
S-cross section area [m2]