Fuel system with liquid ring pump with centrifugal air/fuel separator

An engine mounted fuel system for an aircraft having a fuel tank, comprising:

• a main fuel pump;
• a boost pump unit for drawing fuel from the fuel tank and operably supplying it to the main fuel pump, the boost pump unit including:
• a liquid ring pump having an inlet and an outlet;
• an air/fuel separator having an inlet and first and second outlet ports, the inlet operably fluidly coupled to the outlet of the liquid ring pump, the air/fuel separator having an arcuate flow path extending from the inlet to the first and second outlet ports, wherein the first outlet port is in fluid communication with a radially outer portion of the arcuate flow path and the second outlet port is in fluid communication with a radially inner portion of the arcuate flow path;
• and
• a return line connected directly to the first outlet port and configured to return fuel to the liquid ring pump.

A method of supplying fuel to a combustor of an aircraft having a fuel tank, the method comprising:

• drawing fluid from the fuel tank using suction from a boost pump unit including:
• a liquid ring pump having an inlet and an outlet;
• an air/fuel separator having an inlet and first and second outlet ports, the inlet operably fluidly coupled to the outlet of the liquid ring pump, the air/fuel separator having an arcuate flow path extending from the inlet to the first and second outlet ports, wherein the first outlet port is in fluid communication with a radially outer portion of the arcuate flow path and the second outlet port is in fluid communication with a radially inner portion of the arcuate flow path;
• a return line connected directly to the first outlet port and configured to return fuel to the liquid ring pump;
• and
• returning fuel from the air/fuel separator to the liquid ring pump through the first outlet port.