System for delivering fuel into a gas turbine engine combustion chamber

Abstract

The invention relates to a system for delivering and mixing fuel in a combustion chamber of a gas turbine engine. An injection nozzle assembly for a combustion chamber comprises a minimum of three high-pressure injection nozzles with a continuous spray angle for injecting liquid fuel into a hot chamber via special ports, wherein the outside of an injection nozzle housing and of the hot chamber are blown with a cooling airflow. The mixing of fuel and air takes place only in the inner part of the hot chamber and the quality and intensity of the mixing process is regulated by air delivery ports in the front part of the hot chamber. Adjusting the total area of the ports in the front part of the hot chamber, the angle of inclination of the ports in relation to the axis of the spray angle of the injection nozzles, and the diameter of the ports makes it possible to increase the intensity with which the fuel is mixed with oxidizer, shift the combustion front along the axis of the hot chamber, and control the shape of the fuel combustion flame. The invention makes it possible to increase the lifespan of the fuel injection nozzles and to control the fuel combustion region inside the hot chamber.

Description

[0001] Fuel supply system to the combustion chamber of a gas turbine engine

[0002] The invention relates to a system for supplying and mixing fuel in a combustion chamber of a gas turbine engine and can be used in the design of injector modules for the combustion chamber of a gas turbine engine.

[0003] Systems of fuel injection into the combustion chamber are known (patent RU2470171 C2, patent RU 2032857 C1) in which the mixing of fuel and ignition occur in the injector module located directly in the injector, which organizes the process of mixing the fuel with the oxidizer.

[0004] The disadvantage of these methods is the location of the mixing module in close proximity to the combustion zone, which leads to a low service life of the nozzle module with the injector.

[0005] A combustion chamber injector unit is known (patent RU 2511977 C2). The injector unit comprises a ring-shaped plate with injector modules installed on it in several rows, containing fuel and air channels, and a fuel manifold connected to the plate, the cavity of which is connected by fuel channels to the injector modules. More than three concentric rows of injector modules are installed, which are installed with mounting protrusions in blind holes made in the plate. The plate is made convex in the direction of the air flow. The invention is aimed at increasing the completeness of fuel combustion, reducing emissions of harmful substances in all modes and ensuring a uniform temperature field at the outlet of the combustion chamber along the circumference in all modes.

[0006] The disadvantage of this system is the complexity of the design due to the large number of nozzles and its low reliability.

[0007] An interesting solution for the design of a fuel burner module is known (patent RU 2455569 C1). A gas turbine engine burner comprises a swirler and a gas injector for injecting fuel into an air flow in the burner swirler. At least one gas injector is configured to be located in the inlet of the swirler channel. The gas injector comprises at least one tube for supplying fuel. The tube is made with a plurality of diffuser holes distributed along the tube, acting as gas injectors for efficient distribution of fuel in the air flow passing through the tube. The gas injector tube has circular or spiral V-shaped grooves along its outer surface. The diffuser holes are configured to be located in the lower part of the grooves. The invention improves the efficiency of mixing air and burner fuel.

[0008] The disadvantage of the considered solution is the relatively large overall dimensions of the structure due to the need to accommodate gas fuel injectors.

[0009] A combustion chamber of a gas turbine engine with an injector module is known (patent RU 2493492 C1) adopted for a number of features as the closest analogue. The chamber contains a housing, a flame tube having external and internal walls and a ring-shaped plate with injector modules installed on it and a main fuel manifold connected to the plate, the cavity of which is connected by fuel channels to the injector modules, external and internal housings, external and internal casings installed with a gap relative to the external and internal housings. The number of injector modules is made multiple of four. The cavity of the external manifold is connected by fuel channels to each injector module through one external row of injector modules. The cavity of the internal manifold is connected to each injector module through one internal row. The main fuel manifold is connected to the remaining injector modules of both rows.Between the plate and the outer and inner walls of the fire tube, external and internal means for supplying and swirling cooling air with the possibility of supplying air at an acute angle to the fire tube axis, containing blades installed at an angle to the combustion chamber axis, are installed respectively. On the walls of the fire tube, "pockets" are installed around the circumference, made in the form of hollow streamlined profiles directed towards the fire tube axis. In the outer and inner casings, in the rear part along the flow, openings are made. Achieved goals: increasing the completeness of fuel combustion, reducing emissions of harmful substances and ensuring a uniform temperature field at the outlet of the combustion chamber.

[0010] The disadvantage of this design is the location of the nozzles directly in the combustion chamber, which results in their low service life.

[0011] The objectives of this invention are: increasing the service life of the injector module, ensuring good completeness of fuel combustion, developing a simple method for controlling the shape of the fuel combustion zone and the combustion front.

[0012] The set goals are achieved by the following design solutions: at least three injectors, it is not recommended to use an even number of injectors due to the high intensity of resonance phenomena during fuel combustion, operating at a pressure difference of at least 0.7 MPa, are placed in the wall of the combustion chamber blown by a cooling air flow, the air flow also blows around the outer surface of the combustion chamber, fuel is injected into the combustion chamber through special openings in the frontal part of the combustion chamber, the fuel spray sector by the injectors must be continuous, while the spray sector must not touch the walls of the opening for feeding fuel into the combustion chamber, air for fuel combustion is supplied through the frontal wall of the combustion chamber, by increasing the number and diameter of the openings, that is, by increasing the cross-sectional area for the air flow in the frontal wall of the combustion chamber, a shift of the flame front closer to the frontal wall is achieved,by reducing the angle of inclination of the holes in relation to the axis of the nozzle spray sector, a reduction in the intensity of mixing of air with fuel and an extension of the combustion front along the axis of the combustion chamber are achieved.

[0013] The invention is explained by a drawing. Fig. 1 shows an axial section of the combustion chamber. Item 1 - an injector with a continuous fuel spray sector; the total number of installed injectors must be at least three; all injectors are united by a common fuel manifold Item 2. The injector is installed in the wall of the combustion chamber Item 3. The annular-type combustion chamber Item 4 has openings for supplying fuel Item 9 in the frontal part and openings for supplying air Item 10 in its frontal part. The spray sector is marked Item 6. The cooling air flow flows in the combustion chamber from its outer part, flowing around the injector body along the wall of the combustion chamber and along the chamber fairing Item 5. The direction of movement of air and combustion products in the drawing is indicated by arrows Item 7. Position 8 shows openings in the side wall of the combustion chamber for supplying additional volumes of air into the chamber in order to create an excess of oxidizer by the time the combustion products exit the combustion chamber.The diameter of the air supply holes through the front wall is D. Dimensions A and B are the values ​​of the angles of inclination of the air supply holes in relation to the axis of the fuel spray sector of the injector.

[0014] The considered design of the injector module of the combustion chamber of a gas turbine engine ensures a high operating life of the fuel supply system, high-quality mixing of liquid fuel with air during combustion in a wide range of engine operating modes and the ability to control the shape of the fuel combustion region within the combustion chamber.

Claims

4 Invention formula The injector module of the combustion chamber of a gas turbine engine contains high-pressure injectors, at least three with a continuous spray sector, injecting liquid fuel into the interior of the combustion chamber through special openings in it, a manifold for distributing liquid fuel between the injectors, a combustion chamber with the organization of a flow of cooling air along the body of the injector, and from the outer part of the combustion chamber, while the fuel is mixed with air only in the inner part of the combustion chamber to increase the quality of air for mixing the fuel with the air flow of the oxidizer, openings in the frontal part of the combustion chamber are used, the mixing process is regulated by changing the total free cross-sectional area of ​​​​the openings, their location relative to the spray sector, diameter and angle of inclination relative to its axis.

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