Hi, I’m trying to set up a straight pipe single phase (water) flow simulation, with a mass flow BC at the inlet and a pressure BC at the outlet. The outlet is set to atmospheric pressure, and the main goal of this simulation is to calculate the pressure drop over the domain, but when I don’t enter a pressure at the mass inflow and run the simulation, MFIX automatically sets it to atmospheric pressure. How can I get this so that the pressure at the inlet is unspecified? Thanks for any help.
If your fluid is water, then you have set the density to a constant value. The inlet pressure is not used. If you also do not set the pressure in the initial region, then it will be initialized as hydrostatic pressure and your initial pressure drop should be equal to the initial bed weight. To compute the pressure drop, you need to use the pressure in the first fluid cell though, not the ghost cell below the inlet.