Setting Boundary Conditions For Engines/Pumps

I’m kind of new to all this, so I was wondering, when creating an intake manifold, or a carburetor for an engine - or just a pump, do I set the inlet as atmospheric pressure and outlet as x amount of mass flow (based on engine volume and rpm), or do I set the inlet as 0m/s and outlet as 0 absolute pressure (vacuum)?

Hey there, and thanks for reaching out to the forum!

For a flow simulation to be the most robust, it is recommended to use a pressure + velocity combo.

Usually a velocity inlet + pressure outlet, but the opposite pressure inlet + velocity outlet is equally valid, which is the one that you indicate:

  • Inlet pressure at 0 value (gauge pressure)
  • Outlet velocity as mass flow rate, computed from your operating conditions

I would recommend to model it this way.

Thank you very much for clearing that up.