A gas turbine engine for an aircraft. The gas turbine comprises a staged combustion system having pilot injectors and main injectors, a fuel metering system configured to control fuel flow to the pilot injectors and the main injectors, and a fuel system controller. The controller is configured to identify an atmospheric condition, determine a ratio of pilot fuel flow rate for the pilot injectors to main fuel flow rate for the main injectors in response to the atmospheric condition, and inject fuel by the pilot injectors and the main injectors in accordance with said ratio to control an index of soot emissions caused by combustion of fuel therein.

A method for controlling the fuel injection of a turbine engine using a fuel supply circuit. The supply circuit includes a pilot injection line and a main injection line. During a transition of the supply distribution between the pilot injection line and the main supply line, the method includes the following steps: a) determining at least a minimum value to be maintained for a pressure value; b) determining at least one hydraulic quantity of the supply circuit; c) based on the determined hydraulic quantity of the supply circuit, calculating a calculated fuel supply distribution value corresponding to the minimum value to be maintained; and switching the fuel supply distribution to the calculated fuel distribution value.

A method for controlling the fuel injection of a turbine engine using a fuel supply circuit. The supply circuit includes a pilot injection line and a main injection line. During a transition of the supply distribution between the pilot injection line and the main supply line, the method includes the following steps: a) determining at least a minimum value to be maintained for a pressure value; b) determining at least one hydraulic quantity of the supply circuit; c) based on the determined hydraulic quantity of the supply circuit, calculating a calculated fuel supply distribution value corresponding to the minimum value to be maintained; and switching the fuel supply distribution to the calculated fuel distribution value.

Airframe integrated scramjet engines are disclosed. Scramjet engines within the scope of this disclosure may be configured to integrate smoothly with an airframe of a hypersonic flight aircraft or vehicle. The scramjet engine may include capture shape of an inlet configured to capture airflow, a combustor configured for combustion of fuel and air, and an exit shape of a nozzle configured for expansion of the combusted fuel and air to provide hypersonic thrust. In some embodiments, the scramjet engine has a fixed geometry and a transitioning cross-sectional shape over its full length. The scramjet engine is configured to be a component of launch vehicle system.

Airframe integrated scramjet engines are disclosed. Scramjet engines within the scope of this disclosure may be configured to integrate smoothly with an airframe of a hypersonic flight aircraft or vehicle. The scramjet engine may include capture shape of an inlet configured to capture airflow, a combustor configured for combustion of fuel and air, and an exit shape of a nozzle configured for expansion of the combusted fuel and air to provide hypersonic thrust. In some embodiments, the scramjet engine has a fixed geometry and a transitioning cross-sectional shape over its full length. The scramjet engine is configured to be a component of launch vehicle system.

A flow rate per unit time of fuel fed to a gas turbine is calculated. A flow rate per unit time of air fed to the gas turbine is calculated. A turbine inlet temperature is calculated through use of a physical model formula expressing a relationship of input and output of thermal energy relating to a combustor of the gas turbine. A fuel distribution ratio for each of a plurality of fuel supply systems connected to the combustor is calculated based on the turbine inlet temperature.

A passive flow splitting system for use in a turbine engine control system to provide split fuel flow to two fuel manifolds to supply primary and secondary fuel injectors for the particular combustion zones thereof utilizing intentionally different split ratios dependent on ascending or descending combustion fuel flow is provided. The system includes a passive fuel divider valve (FDV) that includes a primary piston and a secondary piston. The primary piston is moveable independently from the secondary piston during a portion of its stroke, and is hydro-locked to the secondary piston during another portion of its stroke. An ecology valve is also provided to purge the fuel from the primary and/or secondary manifolds during different modes of operation. A transfer valve is included to control the position of ecology piston of the ecology valve.

A passive flow splitting system for use in a turbine engine control system to provide split fuel flow to two fuel manifolds to supply primary and secondary fuel injectors for the particular combustion zones thereof utilizing intentionally different split ratios dependent on ascending or descending combustion fuel flow is provided. The system includes a passive fuel divider valve (FDV) that includes a primary piston and a secondary piston. The primary piston is moveable independently from the secondary piston during a portion of its stroke, and is hydro-locked to the secondary piston during another portion of its stroke. An ecology valve is also provided to purge the fuel from the primary and/or secondary manifolds during different modes of operation. A transfer valve is included to control the position of ecology piston of the ecology valve.

A micromixer injector includes a fuel plenum to receive a supply of fuel. A plurality of premixing tubes extend through the fuel plenum. Each tube has a plurality of fuel holes formed therein to receive the supply of fuel for mixing with air in the tube. The micromixer has a tapering profile such that an overall inlet area of the plurality of premixing tubes on an upstream face of the micromixer is larger than an overall outlet area of the plurality of premixing tubes on a downstream face such that the plurality of premixing tubes are relatively spaced-apart at the upstream face and more densely packed at the downstream face. Additionally, an air inlet of each tube has a first geometrical shape and the outlet of each tube has a second geometrical shape that is different from the first geometrical shape.

A micromixer injector includes a fuel plenum to receive a supply of fuel. A plurality of premixing tubes extend through the fuel plenum. Each tube has a plurality of fuel holes formed therein to receive the supply of fuel for mixing with air in the tube. The micromixer has a tapering profile such that an overall inlet area of the plurality of premixing tubes on an upstream face of the micromixer is larger than an overall outlet area of the plurality of premixing tubes on a downstream face such that the plurality of premixing tubes are relatively spaced-apart at the upstream face and more densely packed at the downstream face. Additionally, an air inlet of each tube has a first geometrical shape and the outlet of each tube has a second geometrical shape that is different from the first geometrical shape.