It might seem like a really stupid question, But i'm getting into flying the FBW A320 in MSFS2020 and I have no idea what the fuel pumps are for in the A320, please may someone explain and help a newbie out? Thanks
What is the purpose of the fuel pumps in the A320?
Fuel for the A320 is located in each wing and a center fuselage tank. These fuel pumps are primarily used to provide positive pressure to supply the fuel to the engines. If the fuel pumps fail in a wing tank, suction valves allow fuel to flow via gravity to the engines. (no suction valves available for the center tank).
A more complex and comprehensive explanation regarding secondary uses of the fuel pumps is available if required, but it's a fairly simple principle.
Non-Airbus specific: You normally have an engine driven fuel pump (EDP) at the engines, supplemented by electric boost pumps in the wing tanks. The engine driven pump provides direct pressure to the fuel control system on the engine itself, always well beyond what the engine needs, with excess fuel continuously returned to the tank, usually referred to as "motive flow".
The electric pumps in the wing tanks are to pressurize the lines to the EDP inlet so the EDP doesn't have to suck fuel all the way from the wing in critical situations, and they're also there as a backup to the EDP itself. You may also have electric pumps to handle fuel transfer and crossfeed functions.
The return "motive flow" from the EDP is also used to run ejector scavenge pumps, venturi pumps with no moving parts, like those plastic gadgets you hooked up to a garden hose to drain waterbeds back in the day. The scavenge pumps draw fuel from the tank extremities to a "collector tank" usually a well at the inboard end of the larger tank, open to the rest of the tank at the top and kept always overflowing by the scavenge pumps, and within which the electric boost pump will normally reside.