A multi-stage fluid pump system can include a first stage configured to provide a first pressure and a second stage configured to provide a second pressure. The pump system can be configured to prevent output of the second stage in a first stage mode such that only the first pressure is output from the first stage and second stage and to allow output of the second stage in a multi-stage mode such that there is a combined pressure output from the first stage and the second stage.

A multi-stage fluid pump system can include a first stage configured to provide a first pressure and a second stage configured to provide a second pressure. The pump system can be configured to prevent output of the second stage in a first stage mode such that only the first pressure is output from the first stage and second stage and to allow output of the second stage in a multi-stage mode such that there is a combined pressure output from the first stage and the second stage.

Methods and systems of operating a gas turbine engine in a low-power condition are provided. In one embodiment, the method includes supplying fuel to a combustor by supplying fuel to a first fuel manifolds and a second fuel manifold of the gas turbine engine. The method also includes, while supplying fuel to the combustor by supplying fuel to the first fuel manifold: stopping supplying fuel to the second fuel manifold; and using a pump to drive gas into the second fuel manifold to flush fuel in the second fuel manifold into the combustor and hinder coking in the second fuel manifold and associated fuel nozzles.

Methods and systems of operating a gas turbine engine in a low-power condition are provided. In one embodiment, the method includes supplying fuel to a combustor by supplying fuel to a first fuel manifolds and a second fuel manifold of the gas turbine engine. The method also includes, while supplying fuel to the combustor by supplying fuel to the first fuel manifold: stopping supplying fuel to the second fuel manifold; and using a pump to drive gas into the second fuel manifold to flush fuel in the second fuel manifold into the combustor and hinder coking in the second fuel manifold and associated fuel nozzles.

To control an engine shutdown in an aircraft, a control system includes a fuel supply shut-off member, a control member with a set of switches, a first switch on an electrical power supply link of the fuel supply shut-off member and second switches connected to avionics of the aircraft, the set of switches switching position on an engine shutdown command. An engine shutdown confirmation unit includes a third switch on the electrical power supply link, the third switch in open position by default. The engine shutdown confirmation unit includes electronic circuitry configured to switch the third switch over to closed position when a predefined quantity Q of switches of the control member switches position within a sliding window of predefined duration and, otherwise, keeps the third switch in open position. Thus, it is ensured that the engine shutdown is intentional.

To control an engine shutdown in an aircraft, a control system includes a fuel supply shut-off member, a control member with a set of switches, a first switch on an electrical power supply link of the fuel supply shut-off member and second switches connected to avionics of the aircraft, the set of switches switching position on an engine shutdown command. An engine shutdown confirmation unit includes a third switch on the electrical power supply link, the third switch in open position by default. The engine shutdown confirmation unit includes electronic circuitry configured to switch the third switch over to closed position when a predefined quantity Q of switches of the control member switches position within a sliding window of predefined duration and, otherwise, keeps the third switch in open position. Thus, it is ensured that the engine shutdown is intentional.

In a one embodiment, a gas turbine system that includes a first pump that supplies distillate fuel to a combustor. A second pump that supplies fuel oil to the combustor. A fuel selection unit that controls a first flow of distillate fuel and a second flow of fuel oil to the combustor. A controller that receives feedback from a sensor and in response to the feedback from the sensor controls the fuel selection unit to start the gas turbine system on the fuel oil.

A fluid pump is shown, comprising: a chamber comprising an inlet and an outlet, the outlet comprising a non-return valve, the chamber having a cavity comprising a cylinder; a piston slidably disposed within the cylinder; and a Tesla valve in fluid communication with the inlet, wherein the fluid pump is configured to pump fluid from the inlet to the outlet by reciprocation of the piston within the cylinder.

A fluid pump is shown, comprising: a chamber comprising an inlet and an outlet, the outlet comprising a non-return valve, the chamber having a cavity comprising a cylinder; a piston slidably disposed within the cylinder; and a Tesla valve in fluid communication with the inlet, wherein the fluid pump is configured to pump fluid from the inlet to the outlet by reciprocation of the piston within the cylinder.

A fuel delivery system for a gas turbine engine comprises a cryogenic fuel tank, a first fuel line for connection to the cryogenic fuel tank, a fuel pump connected to receive fuel via the first fuel line, a plurality of fuel lines connecting the fuel pump to a combustor of the gas turbine engine, a controller configured to operate the fuel delivery system, a purge gas tank connected to the first fuel line and configured to store a purge gas for purging the plurality of fuel lines and a fuel gas tank connected to the first fuel line and configured to store a fuel gas for flushing purge gas from the plurality of fuel lines.