Fuel supply system and fuel supply method for aircraft gas turbine engine

A fuel supply system comprising:

• a gear pump that increases a pressure of fuel flowing in from a system inlet and discharges the fuel;
• a metering section that is disposed downstream of the gear pump and includes an orifice and a check valve connected in parallel with each other;
• a minimum pressurizing check valve that is disposed between the metering section and a system outlet;
• and
• a controller, wherein
• the check valve closes when a rotation speed of the gear pump is less than an upper threshold, and opens when the rotation speed of the gear pump is equal to or more than the upper threshold,
• the minimum pressurizing check valve includes a cylinder and a piston movable back and forth in the cylinder,
• the cylinder has an internal space partitioned by the piston into a first chamber that communicates with an outlet of the metering section through an inflow port and a second chamber that communicates with the system inlet, the piston receiving a force in a direction toward the first chamber from a spring disposed in the second chamber,
• a side wall of the cylinder is provided with an outflow port that is an opening through which the inflow port and the system outlet communicate with each other, an opening degree of the outflow port is adjusted as the piston moves back and forth, and
• the minimum pressurizing check valve keeps a differential pressure between the system inlet and the outlet of the metering section constant and variably adjusts an opening degree of the outflow port in a range of 0 to 100% when the rotation speed of the gear pump is equal to or more than a lower threshold and is equal to or less than an intermediate threshold, the lower threshold being smaller than the upper threshold, the intermediate threshold being more than the lower threshold and smaller than the upper threshold,
• the opening degree of the outflow port is 0% or more when the rotation speed of the gear pump is equal to the lower threshold and a pressure at the system inlet is higher by a predetermined maximum deviation than a median of fluctuations to be assumed, and
• the opening degree of the outflow port is equal to 100% or less when the rotation speed of the gear pump is equal to the intermediate threshold and the pressure at the system inlet is lower by the predetermined maximum deviation than the median of the fluctuations.