A system for providing ignition and pressurization of hypersonic vehicles is disclosed. The system combines the pressurization, barbotage and ignition functions into a single system saving mass and volume and simplifying the hypersonic vehicle plumbing. A monopropellant fuel such as Tridyne is used to pressurize a fuel tank, warm the fuel as it enters fuel injectors, and provide barbotage of the fuel just prior to its injection into a combustion chamber.

A power plant includes a gas turbine including a turbine extraction port that is in fluid communication with a hot gas path of the turbine and an exhaust duct that receives exhaust gas from the turbine outlet. The power plant further includes a first gas cooler having a primary inlet fluidly coupled to the turbine extraction port, a secondary inlet fluidly coupled to a coolant supply system and an outlet in fluid communication with the exhaust duct. The first gas cooler provides a cooled combustion gas to the exhaust duct which mixes with the exhaust gas to provide an exhaust gas mixture to a heat exchanger downstream from the exhaust duct. The power plant further includes a fuel heater in fluid communication with the outlet of the first gas cooler.

Systems and methods for preheating fuel in a gas turbine engine are provided. In one embodiment, a system may include a gas turbine engine, a fuel line in fluid communication with the gas turbine engine, a gas turbine compartment disposed about the gas turbine engine, and a first conduit in fluid communication with the gas turbine compartment. The first conduit may include ventilation discharge air from the gas turbine compartment. The system also may include a first heat exchanger in communication with the fuel line and the first conduit. The first heat exchanger may be configured to exchange heat between the fuel and the ventilation discharge air from the gas turbine compartment.

A method of operating a gas turbine engine, the engine including an engine core with a turbine, a compressor, a combustor arranged to combust a fuel, and a core shaft connecting the turbine to the compressor; a fan upstream of the engine core; a fan shaft; a main gearbox that receives an input from the core shaft and outputs drive to the fan via the fan shaft; a primary oil loop system to supply oil to lubricate the main gearbox; and a heat exchange system to transfer heat between the oil and the fuel, the oil having an average temperature of at least 180? C. on entry to the heat exchange system at cruise conditions. The method includes transferring heat from the oil to the fuel to lower the fuel viscosity to a value of less than or equal to 0.58 mm.sup.2/s on entry to the combustor at cruise conditions.

There is provided a method of operating a gas turbine engine. The gas turbine engine comprises a staged combustor having an arrangement of fuel spray nozzles in which fuel flow is biased to a subset of the nozzles adjacent one or more ignitors during a re-light procedure. The method comprises transferring heat from the oil to the fuel before the fuel enters the combustor so as to lower the fuel viscosity to 0.58 mm.sup.2/s or lower on entry to the combustor at cruise conditions. Also disclosed is a gas turbine engine.

It is widely appreciated that renewable sources of energy are desirable. In particular, in recent years the development of biodiesel has been encouraged in order to find a replacement for fossil fuels in internal combustion engines. Typically, such biodiesel is based on triacylglycerols of vegetable origin. Animal fat, due to its different chemical composition and production process presents additional challenges when attempted to be used as a source of fuel. Most known methods require extensive processing of naturally occurring fats in order for them to be usable in conventional engines. According to the present invention, there is provided a method of oxidizing organic fats within an internal combustion engine to generate power by applying a first electrical charge to an oxidizer (e.g. air) and applying a second electrical charge to the organic fat opposite in polarity to the first electrical charge. In this way, constituents of the organic fat to be oxidized are attracted to the oxidizer, in preference to an interior surface of the combustion chamber. Thus, carbonization of the interior surface of the combustion chamber is reduced, as material contributing to carbonization is retained within exhaust gas.

A method of operating a gas turbine engine, the engine including an engine core with a turbine, a compressor, a combustor arranged to combust a fuel, and a core shaft connecting the turbine to the compressor; a fan upstream of the engine core; a fan shaft; a main gearbox that receives an input from the core shaft and outputs drive to the fan via the fan shaft; a primary oil loop system to supply oil to lubricate the main gearbox; and a heat exchange system to transfer heat between the oil and the fuel, the oil having an average temperature of at least 180? C. on entry to the heat exchange system at cruise conditions. The method includes transferring heat from the oil to the fuel to lower the fuel viscosity to a value of less than or equal to 0.58 mm.sup.2/s on entry to the combustor at cruise conditions.

A combustor for a gas turbine, including: an axial fuel stage fuel injector; and a passively-actuated valve for selectively directing a supply of fuel to the axial fuel stage fuel injector based on a characteristic of the fuel.

A heating device operating with liquid fuel in the single-line mode includes a fuel pump which draws fuel from a supply tank and delivers it into a pressure line region communicating with an atomiser nozzle opening into a combustion chamber, wherein excess fuel is returned from the pressure region to the suction side of the fuel pump by way of a pressure regulator, a return line and a bypass line. Arranged between the return line and the bypass line is a venting apparatus including an actuating element which is reciprocable between an operating position and a venting position and which in the operating position connects the return line to the bypass line to reliably seal the medium in the lines towards the exterior and in the venting position connects the return line to the exterior of the heating device and in that case closes the bypass line.

A method of operating a gas turbine engine, the gas turbine engine including an engine core comprising a turbine, a compressor, a combustor arranged to combust a fuel, and a core shaft connecting the turbine to the compressor; a fan located upstream of the engine core; a fan shaft; a main gearbox that receives an input from the core shaft and outputs drive to the fan via the fan shaft; a primary oil loop system arranged to supply oil to lubricate the main gearbox; and a heat exchange system arranged to transfer heat between the oil and the fuel, the oil having an average temperature of at least 180? C. on entry to the heat exchange system at cruise conditions. The method includes controlling the heat exchange system so as to raise the fuel temperature to at least 135? C. on entry to the combustor at cruise conditions.