KR20170104517A - Turbine engine combustion assembly - Google Patents

Abstract

The present invention relates to a turbine engine combustion assembly comprising an annular flame tube (22) including a front wall (23), a rear wall (24) and a bottom (22) disposed opposite the engine shaft 21); An injection wheel (41) partially projected toward the bottom of the flame tube (21) and rotated by the engine shaft (30) configured to inject fuel into the flame tube by centrifugal force; And at least one injector (35) capable of depositing a film of fuel on the injection wheel (41), wherein the injector (35) comprises a front wall (23) or a rear wall (24) The injection port 37 of the injector communicates with the tube 21 so as to face the portion of the injection wheel 41 located inside the flame tube 21. [ do.

Description

Turbine engine combustion assembly

The present invention relates to the field of combustion assemblies for turbine engines, and more particularly to an apparatus for injecting fuel into combustion chambers of such assemblies.

The turbine engine generally includes a fan, at least one compressor stage, such as a high pressure compressor and a low pressure compressor, a combustion chamber, at least one turbine stage, for example a high pressure turbine, and a low pressure turbine, A turbine, and an exhaust nozzle.

Brief Description of the Drawings Figure 1 is a longitudinal section view schematically showing a combustion assembly 1 of an embodiment of a turbine engine according to the prior art.

The combustion assembly 1 is communicated with a compressor (not shown) on the upstream side (left side in FIG. 1) and with a distributor on the downstream side, which compresses compressed air through the diffuser into the combustion assembly And the distributor itself is connected to a high pressure turbine (not shown).

The combustion assembly 1 is defined by an annular outer casing 2 and an inner casing 3, and the inner casing extends along the longitudinal axis X-X 'inside the outer casing.

The combustion assembly 1 includes a "flame tube" or "combustion chamber"

The flame tube is arranged between the two casings, i.e. the outer casing 2 and the inner casing 3, and has a front wall 5 and a rear wall 6, (X-X ').

The front wall 5 and the rear wall 6 have a bent annular shape and are connected to the inner casing 3 on both sides of the centrifugal injection wheel 7 on the upstream side and to the outer casing 2 and the inner side on the downstream side, And is connected to the casing 3.

This type of flame tube is referred to as "annular" and extends around the longitudinal axis X - X 'of the combustion assembly 1.

The front wall 5 and the rear wall 6 are generally spaced apart from the outer casing 2 and the inner casing 3 to form an annular air supply duct 8 surrounding the flame tube 4 .

The flame tube 4 comprises a plurality of successive zones from the upstream to the downstream, namely a main zone 9 followed by the injection wheel 7 and a middle zone 10 at the bend of the tube, The dilution tube 11 is located.

Air enters the flame tube 4 through a number of intake ports 12 provided through the front wall 5 and through a number of intake ports 13 provided through the rear wall 6, ). ≪ / RTI >

The centrifugal injection tube 7 is mounted on the engine shaft 15 and is rotationally driven by the engine shaft. The engine shaft 15 is coaxial with the longitudinal axis X - X 'of the combustion assembly 1.

The combustion assembly also has a plurality of injectors 16 that are uniformly distributed around the engine shaft 15. The injectors 16 are disposed between the engine shaft 15 and the inner casing 3 which also comprises the bottom (or "inner side") of the flame tube 4 (with respect to the longitudinal axis X-X ').

Each injector 16 emits fuel axially parallel to the longitudinal axis X-X 'toward the front face 17 of the injection wheel 7, which is the upstream face of the combustion assembly 1 (see arrow i) ).

As the injection wheel 7 is rotationally driven, the film of the fuel in contact with the front face 17 receives centrifugal force and is radially displaced toward the outside of the wheel (see arrow j).

At the annular peripheral edge of the wheel 7, a plurality of radial holes 19 are perforated at regular intervals.

The fuel subjected to the centrifugal force passes through the holes 19 and is radially directed toward the flame tube 4 (arrow k) with respect to the engine shaft 15 and atomized into very fine droplets, So that mixing with compressed air becomes easy.

This type of combustion assembly with centrifugal injection wheels has many advantages, especially in the case of miniature engines such as helicopter engines. The advantages are:

- it is not necessary to have a preferred type of injector,

- the injectors are not affected by the viscosity of the fuel associated with the type of fuel and ambient temperature,

- the casing of the turbine has a simple structure with low mass and hence low cost,

On the one hand, the corresponding emissions between the emissions of nitrogen monoxide (NOx), on the other hand, the emissions of carbon monoxide (CO) and unburned hydrocarbons (HC), can be the lowest compromise of all aviation combustion systems.

However, this type of combustion assembly also has disadvantages associated with the location of the injectors, which are located below the flame tube in the vicinity of the engine shaft and thus are oriented toward the interior of the combustion assembly. Turbine engines are now used with increasingly higher temperature rise cycles to reduce the fuel consumption rate, which causes caulking (i.e., solidification) of the fuel. Thus, in order to prevent failures (e.g., failure of the shaft due to solidified fuel ("coke"), premature wear of high temperatures due to poor fuel distribution, or engine start failure due to obstruction of fuel intake) It is necessary to wash the labyrinth seals which are arranged in the labyrinth seals more frequently.

A large portion of the turbine engine can then be moved to allow access to the injectors lying in the center position, to allow for washing and / or replacement of the injectors, and to access the labyrinth seals positioned adjacent the injection wheel It is necessary to disassemble (and thus separate the helicopter engine). In fact, it is not possible to replace the injector with the engine in its original position, which adds additional operation and costs and increases the down-time of the helicopter.

Moreover, in a combustion assembly similar to that shown in Figure 1, the diameter of the injection wheel is substantial, which requires that there is sufficient space between the engine shaft 15 and the edge of the wheel 7 to place the injectors 16 It is because. As a result, the injection wheel has a significant mass and is subjected to considerable force due to its rotational speed.

U.S. Patent No. 4,040,251 describes a combustion assembly of the type described above in which the injector and its supply tube are disposed within the thickness of the inner casing and flame tube bottom. The injection port of the injector leads to an opening provided at the bottom for the passage of the injection wheel.

With the combustion assemblies described above, access to the injector is difficult and therefore complicated and costly to maintain.

It is an object of the present invention to provide a combustion assembly which is a combustion assembly of the type described above, but which can overcome the above-mentioned disadvantages.

In particular, it is an object of the present invention to propose a combustion assembly that can easily disassemble the injector (s) of a flame tube without the need to disassemble the entire turbine engine and separate the turbine engine from the airframe of the helicopter.

To this end,

An annular flame tube comprising a front wall having an upstream zone directed upstream of the combustion assembly, a rear wall having an upstream zone directed upstream of the combustion assembly and a bottom disposed opposite the engine shaft,

- an injection wheel rotationally driven by the engine shaft coaxial with the longitudinal axis (X-X ') of the combustion assembly, partially protruding into the flame tube through the bottom of the flame tube, A spray wheel configured to atomize, and

And at least one injector capable of depositing a film of fuel on the injection wheel.

According to the invention, the injector is arranged to penetrate the upstream zone of the front wall of the flame tube or through the upstream zone of the rear wall, and to allow the injection orifice of the part of the injection wheel As shown in FIG.

This feature of the invention makes it much easier to disassemble the injectors because there is no longer a need to access the area located between the bottom of the flame tube and the drive shaft of the injection wheel. This decomposition can be carried out at a location where the machine on which the combustion assembly is mounted (e.g., a helicopter) is located.

Advantageously and according to a first variant embodiment, the injector is arranged to penetrate an upstream zone of the front wall of the flame tube, the injection wheel being curved at the periphery upstream of the combustion assembly to have an annular edge, A plurality of radial spray holes are drilled and the injector is introduced into the flame tube opposite the entire surface of the annular periphery of the spray wheel located in the flame tube.

Advantageously, and in accordance with another variant embodiment, the injector is arranged to penetrate an upstream zone of the rear wall of the flame tube, the injection wheel being curved around the downstream side of the combustion assembly to have an annular edge, And the injector is introduced into the flame tube opposite the rear surface of the annular peripheral portion of the injection wheel located in the flame tube.

Advantageously, and in accordance with another alternative embodiment, the injection wheel is a solid body and has an annular fuel receiving radiating surface projecting into the flame tube, wherein the injector faces the annular fuel receiving surface and into the flame tube do.

In the preferred case, the injector is oriented to discharge fuel to the fuel receiving surface of the injection wheel in a tangential line.

It is possible for the fuel receiving surface of the injection wheel to form an angle alpha with the axis of the injector of the injector, which angle is from 90to 180 degrees.

According to a first modification, in the combustion assembly according to the present invention, the axis of the jetting orifice of the injector extends in a plane including the axis of the jetting wheel and perpendicular to the central plane of the wheel orthogonal to the axis of the jetting wheel.

According to a second variant, in the combustion assembly according to the invention, the axis of the injection opening of the injector is not orthogonal to the center plane of the wheel which is orthogonal to the axis of the injection wheel.

The present invention also relates to a turbine engine comprising the above combustion assembly

Other features, objects, and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of illustration and not limitation, possible embodiments of the invention.
1 is a longitudinal sectional view showing a combustion assembly according to an embodiment of the prior art;
Figures 2 and 3 are schematic, longitudinal section views of two embodiments of a turbine engine combustion assembly in accordance with the present invention.
4 is a schematic cross-sectional view of the combustion assembly taken along the plane of line IV-IV in Fig. 3;

A first embodiment of the present invention will now be described with reference to Fig.

Figure 2 schematically shows the combustion assembly 20, which is brief in comparison with Figure 1 because it shows only the flame tube and the injection assembly.

The flame tube 21 includes a bottom 22 (or inner side of a flame tube), a front wall 23, and a rear wall 24. The bottom 22 connects the front wall 23 and the rear wall 24.

In the case of the preceding combustion assembly 1, the flame tube 21 is annular and extends about the longitudinal axis X - X 'of the combustion assembly 20.

The bottom 22 is provided with an opening 25 through which a portion of the injection wheel 26 can pass into the flame tube 21. In other words, the injection wheel 26 partially protrudes into the bottom of the flame tube 21.

The front wall 23 has an upstream zone 230 upstream of the combustion assembly and the turbine engine (left side in FIG. 2) in which a plurality of intake ports 28, opposite the main combustion zone 28 of the flame tube, 27) are perforated.

Likewise, the rear wall 24 has an upstream zone 240 upstream of the combustion assembly and turbine engine in which a plurality of intake ports 29, opposite the main combustion zone 28 of the hearth tube, .

The injection wheel 26 is rotationally driven by the engine shaft 30 which is coaxial with the vertical axis line X-X '. The injection wheel has a front face 31 upstream of the combustion assembly and a rear face 32 opposite the downstream face.

The injection wheel 26 is curved around its periphery to define a peripheral annular edge 33 and has a peripheral annular rim with a radially outwardly directed radial orientation about the longitudinal axis X- (34) are perforated, preferably at regular intervals. These holes 34 may be orifices or slots.

Compared with the prior art injection wheel 7 (see Fig. 1), since it is in the interior of the flame tube up to the annular peripheral edge of the injection wheel as well as the annular edge 260 of the disk constituting the injection wheel 26, It will be noted that the injection wheel 26 is further inserted into the flame tube 21. The annular edge portion 260 is located at an extension of the edge 33.

The inner surface of the annular edge 33 is located a distance D1 from the bottom 22 of the flame tube 21 opposite the engine shaft 30. [

 The combustion assembly also includes one or more injectors 35, which in Fig. 2 can only see one of them.

The present scavenger 35 is connected to the fuel supply tube 36.

Unlike the prior art, the injector 35 is arranged to pass through the front wall 23 of the flame tube 21, preferably the upstream section 230 of the flame tube, where the air inlets 27 are provided. Further, the injector 35 is disposed such that its injection port 37 is connected to the inside of the flame tube 21.

To this end, it will be appreciated that the distance D1 is sufficient to allow the passage of the fuel jet leaving the jetting end 37 of the jetting device 35. [

The injection operation is as follows. The fuel exiting the injector 35 exits through the injection port 37 and is discharged toward the front face 31 of the portion 260 of the injection wheel 26 to form the fuel film F. [

Under the influence of the centrifugal force due to the rotation of the injection wheel 26, the fuel film is displaced toward the periphery of the wheel and passes through the holes 34, which, in contact with the air surrounding the wheel, 21 to the very fine droplets G dispersed in the inside of the nozzle.

The sprayer 13 is arranged to pass through the front wall 23 of the flame tube, so that disassembling is facilitated. Preferably, the arrangement of the injectors will be suitable for causing the injectors to be withdrawn from the front wall 23.

Advantageously, the bottom 22 of the flame tube 21 can also be located closer to the engine shaft 30, so that the diameter of the injection wheel 26 is less than the diameter of the prior art injection wheel shown in FIG. 1 It is small. In this regard, it will be appreciated that Figures 1 and 2 are not drawn to scale.

If the diameter of the injection wheel 26 is small, its mass is also smaller than that of the prior art wheel, and as a result its mechanical strength is also improved.

Another embodiment of the present invention will now be described with reference to FIG. The same elements are denoted by the same reference numerals and will not be described in detail again.

The injection wheel is indicated at 41. The injection wheel is rotationally driven by the engine shaft (30).

This injection wheel is different from the injection wheel 26 in that it is a solid body, that is, the injection holes 34 are not perforated. The peripheral edge 42 of the injection wheel is open like a trumpet to define a preferably flat, circular radiating surface 43 for receiving the fuel film F. [

The sprayer 35 is positioned so that the jetting port 37 faces this surface 43.

The axis of the jetting port 37 forms an angle alpha with the fuel receiving surface 43. This angle alpha is advantageously between 90 [deg.] And 180 [deg.]. If the angle is 180, fuel injection occurs tangentially to the surface 43.

Considering that the center plane P of the wheel 41 is orthogonal to the axis of the engine shaft 30 driving the wheel, the axis of the injection port 37 of the injector 35 is orthogonal to P And extends in a plane P1 including the axis of the engine shaft 30. [ In Fig. 3, the plane P1 corresponds to the plane of the paper shown in the figure, and in Fig. 4, the plane Pl is shown with a dot-dash line.

However, it is also possible to orient the axis of the jetting port 37 so as not to be orthogonal to P. In other words, this axis is protruded or separated from the plane Pl corresponding to the plane of Fig. In Fig. 4, this axis is indicated by X1-X'1.

In this embodiment, the injector 35 is advantageously inserted into the flame tube 21 less deeply than the embodiment of FIG. 2, since the injection orifice need not reach the area located below the annular edge 33 of the injection wheel. . It is sufficient that the fuel is injected onto the surface 43 by the injector. This facilitates disassembly of the sprayer 35. [

As before, the fuel film F receives the centrifugal force generated by the wheel 41 and is atomized in the form of fuel droplets G.

According to this embodiment of the present invention, since the through hole is not perforated, it becomes possible to provide the injection wheel 41 having a structure which is considerably simple and has good mechanical durability. Since the bottom 22 of the flame tube 21 may be closer to the engine shaft 30, the diameter is also smaller than in the prior art. Finally, the combustion takes place substantially only on one side of the injection wheel 41, here on the left side of Fig.

Moreover, it will be appreciated that alternative embodiments of the invention are possible. In particular, the injector 35 may be positioned to pass through the rear wall 24 of the flame tube 21, preferably through the upstream zone 240 of the rear wall.

In this case, and when the injection wheel 26 is made according to the embodiment of FIG. 2, the annular edge 33 is turned toward the downstream side of the combustion assembly 20 and fuel injection takes place at the rear face 32 of the wheel .

The receiving surface 43 is oriented so as to face the rear wall 24 when the injector is positioned to penetrate the rear wall 24 and the injection wheel 41 corresponds to the embodiment of Fig.

Other possible inclination of the axis of the jetting port 37 and other values of the angle [alpha] described above can also be applied to this variant embodiment.

Finally, according to another variant embodiment, it is possible that the flame tube 21 is made of a plurality of parts which are assembled using the flange 50, in which case disassembly is facilitated.

Claims (9)

A turbine engine combustion assembly (20) comprising:
A front wall 23 having an upstream section 230 directed upstream of the combustion assembly 20, a rear wall 24 having an upstream section 240 upstream of the combustion assembly 20, An annular flame tube (21) comprising a bottom (22) arranged opposite to the annular flame tube (30)
- injection wheels (26, 41) rotationally driven by the engine shaft (30) coaxial with the longitudinal axis (X-X ') of the combustion assembly (20) (26, 41) partially protruding into the flame tube (21) and configured to atomize the fuel in the flame tube by centrifugal force, and
- a turbine engine combustion assembly comprising at least one injector (35) capable of depositing a film of fuel on said injection wheels (26, 41)
The injector 35 is arranged to pass through the upstream section 230 of the front wall 23 of the flame tube 21 or through the upstream section 240 of the rear wall 24 and through the injection port 37 of the injector, Is arranged to be drawn into the tube (21) opposite the part of the injection wheel (26, 41) located in the flame tube (21). The method according to claim 1,
The injector 35 is arranged to penetrate the upstream zone 230 of the front wall 23 of the flame tube 21,
The injection wheel 26 is curved at the periphery of the upstream side of the combustion assembly to have an annular edge 33,
A plurality of radial spray holes (34) are perforated in the annular edge (33)
Characterized in that the injector (35) is drawn into the flame tube (21) opposite the front face (31) of the annular peripheral portion (26) of the injection wheel located in the flame tube (21). The method according to claim 1,
The injector 35 is arranged to penetrate the upstream zone 240 of the rear wall 24 of the flame tube 21,
The injection wheel 26 is curved around the downstream side of the combustion assembly to have an annular edge 33,
A plurality of radial spray holes (34) are perforated in the annular edge (33)
Characterized in that the injector (35) is introduced into the flame tube (21) opposite the rear face (32) of the annular peripheral portion (260) of the injection wheel located in the flame tube (21). The method according to claim 1,
Wherein the injection wheel (41) is a solid body and has an annular fuel receiving and radiating surface (43) projecting into the flame tube (21)
Characterized in that the injector (35) is drawn into the flame tube (21) opposite the annular fuel receiving surface (43). The method of claim 4,
And the injector (35) is oriented to discharge fuel in a tangential manner to the fuel receiving surface (43) of the injection wheel. The method of claim 4,
Characterized in that the fuel receiving surface (43) of the injection wheel (41) forms an angle (?) With the axis of the injection port (37) of the injector (35) . The method according to any one of claims 4 to 6,
The axis of the jetting port 37 of the jetting device 35 is perpendicular to the plane P of the wheel 41 including the axis 30 of the jetting wheel 41 and orthogonal to the axis of the jetting wheel 41 (P1). ≪ / RTI > The method according to any one of claims 4 to 6,
Characterized in that the axis of the injection port (37) of the injector (35) is not orthogonal to the center plane (P) of the wheel (41) orthogonal to the axis of the injection wheel (41). A turbine engine comprising a combustion assembly according to any one of the preceding claims.

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