Methods and systems of starting a gas turbine engine are provided. During startup, a fuel pressure associated with a primary fuel supply of the gas turbine engine is monitored. A low-pressure event for the primary fuel supply is detected when the fuel pressure falls below a predetermined threshold. Responsive to detecting the low pressure event, an electric backup boost pump is activated by an engine controller to provide fuel to the gas turbine engine.

A fuel system includes a fuel pump formed of a constant-volume pump for changing a discharge flow rate in conjunction with a variation in a speed of revolution of a drive shaft, a boost pump disposed upstream from the fuel pump and formed of a constant-volume pump of which a discharge flow rate per unit of revolution of a drive shaft is greater than that of the fuel pump, a single electric motor rotationally driving the drive shaft of the fuel pump and the drive shaft of the boost pump in a state in which the speeds of revolution thereof are equal to each other, a return flow channel connecting an upstream side and a downstream side of the boost pump, and a relief valve disposed in the return flow channel and opened when an internal pressure of the return flow channel is greater than a reference pressure.

A fuel system includes a fuel pump formed of a constant-volume pump for changing a discharge flow rate in conjunction with a variation in a speed of revolution of a drive shaft, a boost pump disposed upstream from the fuel pump and formed of a constant-volume pump of which a discharge flow rate per unit of revolution of a drive shaft is greater than that of the fuel pump, a single electric motor rotationally driving the drive shaft of the fuel pump and the drive shaft of the boost pump in a state in which the speeds of revolution thereof are equal to each other, a return flow channel connecting an upstream side and a downstream side of the boost pump, and a relief valve disposed in the return flow channel and opened when an internal pressure of the return flow channel is greater than a reference pressure.

A fuel conditioning and control system provides dynamic control and steady state operations of a gas turbine provided fueled by supercritical liquefied petroleum gas (LPG). The fuel conditioning and control system comprises a storage for LPG fuel; a fuel delivery sub-system connecting the storage to turbomachinery; and a control system. The gas turbine includes a gas turbine core control that provides at least one operational data of the gas turbine to the control system. The fuel delivery sub-system includes at least one sensor for sensing at least one property of the LPG fuel in the fuel delivery sub-system, where the at least one sensor providing data on the at least one property of the LPG fuel to the control system. The control system analyzes the data on the at least one property of the LPG fuel and at least one operational data of the gas turbine for dynamic control of LPG fuel to the gas turbine under dynamic and steady state conditions.

A fuel conditioning and control system provides dynamic control and steady state operations of a gas turbine provided fueled by supercritical liquefied petroleum gas (LPG). The fuel conditioning and control system comprises a storage for LPG fuel; a fuel delivery sub-system connecting the storage to turbomachinery; and a control system. The gas turbine includes a gas turbine core control that provides at least one operational data of the gas turbine to the control system. The fuel delivery sub-system includes at least one sensor for sensing at least one property of the LPG fuel in the fuel delivery sub-system, where the at least one sensor providing data on the at least one property of the LPG fuel to the control system. The control system analyzes the data on the at least one property of the LPG fuel and at least one operational data of the gas turbine for dynamic control of LPG fuel to the gas turbine under dynamic and steady state conditions.

A pressure regulating device includes an on-board storage tank, a mixing chamber, first and second lines, a recirculation line, a pressure sensor and a controller. The storage tank stores and supplies cryogenic fuel to a combustion chamber and includes a booster pump. The first line supplies cryogenic fuel in the liquid state and includes a pressurizing pump and a first regulation valve. The second line supplies cryogenic fuel in the gaseous state and includes a compressor and a first control valve. The recirculation line includes a second regulation valve and with a first heat exchanger. The pressure sensor detects the pressure inside the storage tank. The controller receives the pressure and controls the first and second regulation valves, the first control valve, the pressurizing pump, the booster pump and the compressor, as a function of a value of a setpoint pressure inside the storage tank.

A method of pumping fuel in a fuel system of a composite aircraft having a gas turbine engine includes feeding un-heated fuel from a fuel tank to the gas turbine engine, by using an ejector pump to draw the fuel from the fuel tank and feeding the fuel through an engine fuel pump within a main fuel line upstream of the gas turbine engine. Fuel from the main fuel line is bled and directed to the ejector pump via a motive flow pump assembly, the motive flow pump assembly including a motive flow pump generating a motive flow for the ejector pump. The bleed fuel flow is then passed through a hydrophobic fuel screen located upstream of the motive flow pump.

A method of pumping fuel in a fuel system of a composite aircraft having a gas turbine engine includes feeding un-heated fuel from a fuel tank to the gas turbine engine, by using an ejector pump to draw the fuel from the fuel tank and feeding the fuel through an engine fuel pump within a main fuel line upstream of the gas turbine engine. Fuel from the main fuel line is bled and directed to the ejector pump via a motive flow pump assembly, the motive flow pump assembly including a motive flow pump generating a motive flow for the ejector pump. The bleed fuel flow is then passed through a hydrophobic fuel screen located upstream of the motive flow pump.

A fuel pump system can include a motor and a pump connected to the motor. The pump can be configured to receive an inlet flow from an inlet line, to pressurize the inlet flow, and to output a pressurized flow to an output line for an engine. The system can include a bypass line disposed between the outlet line and the inlet line, and a bypass valve disposed on the bypass line and configured to allow pressurized flow to flow to the inlet line in an open state, and to prevent pressurized flow from flowing to the inlet line in a closed state. The bypass valve can be configured to allow pressurized flow to flow to the inlet line to circulate flow and to maintain a constant pressure on the output line.

A fuel pump system can include a motor and a pump connected to the motor. The pump can be configured to receive an inlet flow from an inlet line, to pressurize the inlet flow, and to output a pressurized flow to an output line for an engine. The system can include a bypass line disposed between the outlet line and the inlet line, and a bypass valve disposed on the bypass line and configured to allow pressurized flow to flow to the inlet line in an open state, and to prevent pressurized flow from flowing to the inlet line in a closed state. The bypass valve can be configured to allow pressurized flow to flow to the inlet line to circulate flow and to maintain a constant pressure on the output line.