EP1001223A2 - Gas turbine with rotary fuel injection - Google Patents

Abstract

The gas turbine has a radial or slinger combustion chamber (1) preceded by a radial or diagonal compressor (2) and a turbine part (5) connected to it via an axial rotor shaft (4) with at least one roller bearing (36). Fuel passes through a feed tube (12) in the compressor rotor wheel (2a) into a crossing part (4b) of the rotor shaft in a region of the combustion chamber near the compressor, and via this into combustion chamber radial delivery bores (17). A centrifugal siphon (14) in or upstream of the crossing part before the delivery bores carries fuel. A capillary tube (38) that branches off the delivery siphon on the combustion chamber side, and hence upstream of the delivery bores, carries a sub-flow of fuel to the roller bearing (36) on the turbine part side.

Description

The invention relates to a small gas turbine with a radial or Slinger combustion chamber as well as with a radial compressor or diagonal compressor upstream of the radial or Slinger combustion chamber and a turbine part connected to the latter by means of a rotor shaft which runs in the axial direction and is supported by at least one roller bearing, the fuel passing through A delivery pipe provided in the impeller of the radial compressor / diagonal compressor enters a crossing part of the rotor shaft located in the region of the combustion chamber near the compressor and is fed to the combustion chamber via supply bores running essentially in the radial direction thereof, and in or upstream of the crossing part (es) a supply bores upstream of the supply bores centrifugal siphon through which fuel flows is provided.
Regarding the technical environment, in addition to US 5,526,640, reference is made in particular to the unpublished German patent application 198 46 976.

In a radial combustion chamber with the above-mentioned features, which are usually also known as the Slinger combustion chamber, the fuel is produced by one concentric to the axis of rotation of the radial compressor (under this term also referred to as the diagonal compressors) or the rotor shaft Bore in the compressor impeller or through a delivery pipe provided therein directed to the combustion chamber. It flows due to the rotary motion of the rotor shaft or the compressor impeller due to the resulting centrifugal forces Fuel as a thin film along the wall of the bore or the delivery pipe to directly below the primary zone of the combustion chamber State of the art by a suitable tear-off edge or by individual radially arranged Sprayed nozzles into the primary zone of the combustion chamber.

The pressure difference between the combustion chamber and that at the start of the delivery pipe to balance the horizontal fuel injection point must be a suitable one Seal or conveyor between these locations his. This function can be a so-called centrifugal siphon, which acts as a hydraulic seal works and is shown, for example, in the last-mentioned document. With such a system, the fuel can advantageously be almost pressureless be introduced into the conveyor tube, so that for this an extremely small dimension Fuel pump can be used.

A critical component in such small gas turbines is in particular the turbine part side Rolling bearings for the rotor shaft, since this is in the very hot area is located between the combustion chamber and the turbine disk of the turbine part. This rolling bearing must therefore be cooled and lubricated. Since now such Small gas turbines usually have to be constructed very inexpensively Fuel used as a lubricant and coolant, not a separate lubricating oil system to make necessary. However, a high-pressure fuel pump will then be used again needed, with the help of which a fuel subset to lubricate and Cooling purposes can be injected into the roller bearing or bearings.

It is the object of the present invention to show measures by means of which it is also possible to lubricate or cool the roller bearing on the turbine part side in a small gas turbine without a high-pressure fuel pump according to the preamble of claim 1.
To solve this problem, it is provided that a capillary tube branches off from the centrifugal siphon on the combustion chamber side and in the process upstream of the supply bores, via which a partial fuel quantity is fed to the roller part on the turbine part side. Advantageous training and further education are included in the subclaims.

Fig.1

einen Längsschnitt durch eine erfindungsgemäße Kleingasturbine, in welchem neben der Brennkammer der Radialverdichter sowie das Turbinenteil mit dem zugeordneten Wälzlager dargestellt sind,

Fig.2

das Brennstoffeinspritzsystem aus Fig.1 mit dem Fliehkraftsiphon und dem davon abzweigenden Kapillarrohr in vergrößerter Darstellung, sowie

Fig.3

den Bereich des turbinenteilseitigen Wälzlagers aus Fig.1 in vergrößerter Darstellung.

The invention is explained in more detail with reference to a preferred exemplary embodiment shown in the attached figures, it being possible for all the features described in more detail to be essential to the invention. It shows

Fig. 1

2 shows a longitudinal section through a small gas turbine according to the invention, in which, in addition to the combustion chamber, the radial compressor and the turbine part with the associated roller bearing are shown,

Fig. 2

the fuel injection system of Figure 1 with the centrifugal siphon and the branching capillary tube in an enlarged view, and

Fig. 3

the area of the turbine part-side roller bearing from Figure 1 in an enlarged view.

Reference number 1 denotes a Slinger combustion chamber of a small gas turbine, which - as shown in particular in FIG. 1 - has a radial compressor 2 upstream. The so-called turbine part 5 of the small gas turbine or more precisely the turbine disk 5a of the turbine part 5 is connected to the compressor impeller 2a of this radial compressor 2 via a rotor shaft 4 running in the axial direction 3. The compressor impeller 2a, the rotor shaft 4 and the turbine disk 5a rotate about the so-called central axis 19 of the small gas turbine. For this purpose, the rotor shaft 4 is mounted by means of two roller bearings 35, 36 in the housing of the small gas turbine, designated in its entirety by the reference number 37. As can be seen, a first roller bearing 35 is provided in the inflow region of the compressor impeller 2a and is therefore also referred to as a roller bearing 35 on the compressor part side, while the second roller bearing 36 provided upstream just before the turbine part 5 is also referred to as a turbine part side bearing 36.

The radial compressor 2 conveys one to be fed to the combustion chamber 1 in the direction of the arrow 6 Airflow that is used within the combustion of the further the Combustion chamber 1 supplied fuel is required. Part of this simplicity for the sake of air flow also designated with the reference number 6 due to the differences in the different zones of the small gas turbine Pressure ratios, however, not into the combustion chamber 1, but instead on this or on its end facing the radial compressor 2 on the outside past in the so-called compressor back space 8. Furthermore, a small subset leak air from the combustion chamber also get into the compressor rear space 8. These two air flows mixing in the compressor rear space 8 are generally referred to as leakage air 6a.

The compressor rear space 8 located on the rear side of the compressor impeller 2a must therefore be ventilated, i.e. the leakage air 6a must come from the compressor back space 8 can also be removed again. This is done at least in some areas, here, however, completely hollow rotor shaft 4, or more precisely about the interior 4a. As can be seen, the front is the compressor impeller 2a facing end of the rotor shaft 4 is flange-shaped and represents a so-called Crossing part 4b. Several go through this flange-like crossing part 4b (here preferably three evenly distributed over the circumference of the intersection part 4b) Vent holes 9 through, which thus a connection between the rotor shaft interior 4a and ultimately the compressor rear space 8. in the the rest is via this flange-like crossing part 4b, the rotor shaft 4 with the compressor impeller 2a non-rotatably connected.

Now that the leakage air 6a from the compressor rear space 8 via the ventilation holes 9 reaches the interior 4a of the rotor shaft 4 in the intersection part 4b it is from this via an end region facing the turbine part 5 the discharge shaft 4c provided the rotor shaft 4, which the turbine disk 5a penetrates in a central outlet opening 10, ultimately into the environment dissipated, more precisely via the thrust nozzle not shown here Small gas turbine.

However, not only the leakage air 6a is emitted via the crossing part 4b of the rotor shaft 4 discharged to the compressor rear space 8, but at the same time that in the combustion chamber 1 fuel to be burned supplied to the combustion chamber 1. Like on small gas turbines with Slinger combustion chambers, the fuel is usually used one concentric to the axis of rotation of the radial compressor 2 or the rotor shaft 4 running bore 11 in the compressor impeller 2a or more precisely through a provided therein Delivery pipe 12 ultimately directed to the combustion chamber 1. This leads to in the left-hand beginning area of the conveyor tube 12 with one not shown relatively weakly dimensioned and especially not as a high pressure pump Trained fuel pump from a storage tank, also not shown promotes the fuel for the operation of the small gas turbine, connected Fuel injection tube 13.

The fuel introduced in this way thus passes through the delivery pipe 12 and via a centrifugal siphon 14, which is explained in more detail below, into a preferred centrally in the intersection 4b of the rotor shaft 4, but away from the ventilation holes 9 provided distribution chamber 15, of which several in the radial direction Branch off 16 supply holes 17. About this too in the intersection part 4b provided supply holes 17, which are offset from the vent holes 9 are arranged so that the supply holes 17 and Do not cut vent holes 9, the fuel can therefore ultimately in reach the combustion chamber 1. Three such supply bores are preferred 17 evenly distributed over the circumference of the intersection part 4b.

With regard to the centrifugal siphon 14 described below, which is provided between the delivery pipe 12 and the distribution chamber 15, for the sake of clarity, reference is made in particular to the enlarged illustration in FIG. 2 . The purpose of this centrifugal siphon 14 is to seal the initial area of the fuel injection system, namely the fuel injection tube 13 and the delivery pipe 12, from the combustion chamber 1, in particular in order to ensure excellent controllability of the entire fuel injection system of the small gas turbine even at low speeds and in addition to this to ensure the possibility of a windmill start often desired in small gas turbines as best as possible.

As shown in FIG. 2 , the fuel brought in via the injection tube 13 exits the delivery pipe 12 again under the influence of centrifugal force onto the inner surface of a so-called distributor cone 20 and over this due to a baffle plate 21 provided in the crossing part 4b along the same via one between the free end of the distributor cone 20 and the baffle plate 21 provided first gap space 33 in the radial direction 16 outwards into the area of at least one, but in particular a plurality of axial grooves 22 made in the edge of the baffle plate 21. The fuel then passes through or through these grooves 22 along the Distribution cone 20 side facing away, ie along the side of the baffle plate 21 facing the combustion chamber 1 in the radial direction 16 viewed inward via a so-called second gap space 34, ie in the direction of the central axis 19 into the distribution chamber 15 already described.
Otherwise , one can see in FIG. 2 more precisely a screw connection designated by reference numeral 23, via which the compressor impeller 2a is flanged to the rotor shaft 4 or to the crossing part 4b thereof.

The centrifugal siphon 14 or, more precisely, the one located within it Amount of fuel due to the rotation of the rotor shaft 4 acting centrifugal forces has / have the consequence that in the second gap 34 of the centrifugal siphon 14 a certain There is fuel pressure, i.e. in the second gap space 34 it is current in it located fuel quasi compressed to a certain pressure value. This The fact is now used in such a way that one out of this second gap space 34 Part of the fuel branched off and ultimately the turbine bearing bearing 36 is supplied for lubrication and cooling purposes.

Kapillarrohr" verdeutlicht dabei, daß es sich bei dem eine Brennstoff-Teilmenge dem turbinenteilseitigen Wälzlager 36 zuführenden Element um ein Rohr oder Röhrchen oder dgl. handelt, in welchem sich eine Durchflußbohrung 38a mit einem relativ geringem Durchflußquerschnitt befindet. In diesem Zusammenhang sei ausdrücklich darauf hingewiesen, daß anstelle eines Kapillarrohres (38) auch ein anderes geeignetes Element verwendet werden kann, welches den gleichen Zweck erfüllt, so bspw. ein Schlauch mit relativ geringen Durchflußquerschnitt. Alternativ kann auch eine entsprechend dünne (Durchfluß-)Bohrung (38a) direkt in der Rotorwelle 4 vorgesehen sein, über welche eine Brennstoff-Teilmenge dem turbinenteilseitigen Wälzlager 36 abzweigend vom zweiten Spaltraum 34 des Fliehkraftsiphons 14 zugeführt wird; auch eine derartige (hier der Einfachheit halber nicht figürlich dargestellte) Ausführungsform soll unter den Begriff des Kapillarrohres 38 fallen.For this purpose, a capillary tube 38 branches off from the centrifugal siphon 14 on the combustion chamber side and thereby (with respect to the fuel flow direction) upstream of the supply bores 17, ie from the second gap 34 of the centrifugal siphon 14, via which a partial fuel quantity is fed to the roller bearing 36 on the turbine part side. The term

Capillary tube "clarifies that the element supplying a partial fuel quantity to the roller bearing 36 on the turbine part side is a tube or tube or the like, in which there is a flow bore 38a with a relatively small flow cross section. In this connection, it is expressly pointed out that instead of a capillary tube (38) it is also possible to use another suitable element which serves the same purpose, for example a hose with a relatively small flow cross section Rotor shaft 4 can be provided, via which a partial fuel quantity is fed to the roller bearing 36 on the turbine part branching from the second gap space 34 of the centrifugal siphon 14; such an embodiment (not shown here for the sake of simplicity) is also intended to fall under the term capillary tube 38.

What now the arrangement of the here in the context of a preferred embodiment capillary tube 38 shown in the figure, this is on the inlet side, i.e. suspended in the area of the centrifugal siphon 14, in the crossing part 4b of the rotor shaft 4 or in a suitably arranged receiving bore 39 in the crossing part 4b inserted. The capillary tube 38 then continues within the rotor shaft 4 and in sections in the interior 4a of the same, but in sections also in the wall of the rotor shaft (not denoted by a separate reference number) 4. As can be seen, the capillary tube 38 is suitable for this purpose in the rotor shaft wall inserted blind hole 40 inserted. The capillary tube opens 38 in the closed end of the blind hole 40, one of which is the wall of the Rotor shaft 4 branches off in the radial direction 16 and penetrates bore 41, so that the capillary tube 38 under the influence of the centrifugal siphon 14th and starting from this introduced fuel subset through this hole 41 can get into a so-called bearing annulus 42, in which the turbine part Rolling bearing 36 is arranged.

Said bearing annular space 42 is thus inward in the radial direction 16 the outside of the rotor shaft 4 and in the radial direction 16 to the outside by a not specified section of the housing 37 of the small gas turbine limited. Viewed in the axial direction 3 or in the flow direction of the small gas turbine working gases is the bearing annulus 42 (right side) by the turbine part side Rolling bearing 36 and viewed against the direction of flow (i.e. left side and thus towards the combustion chamber 1) by a labyrinth seal in particular Seal 43 limited. This seal 43 allows a slight passage of combustion chamber gas, i.e. of the gases in the combustion chamber 1, after the figures shown here, but not provided with reference numbers Combustion chamber walls - as is usual with small gas turbines - are not absolutely tight are, so that a fraction of the combustion chamber gas in the Bearing annulus 42 penetrates, there the fuel emerging from the bore 41 entrains and thus initiates this in the axial direction 3 directly into the rolling bearing 36. Consequently the rolling bearing 36 becomes simple and reliable with a fuel subset supplied for lubrication and cooling purposes.

This is removed from the roller bearing 36 due to the passage of the seal 43 Combustion chamber gases supplied in the form of a mist of fuel via the in Axial direction 3 behind the roller bearing 36 bearing back space 44, of which from the fuel subset including the combustion chamber gases in the Working gas flow channel 45 can reach, i.e. discharge takes place via the turbine part 5 ultimately in the area.

Both in FIG. 2 and in FIG. 3 , moreover , it can be seen that the capillary tube 38 in the blind hole 40 is spaced slightly apart from the wall of the rotor shaft 4 over large areas, so that the partial fuel quantity guided in the capillary tube 38 is as little as possible is heated by the hot rotor shaft 4. In this respect, the use of an actual capillary tube 38 is considerably cheaper than if the fuel subset were supplied to the roller bearing 36 via a bore provided directly in the rotor shaft wall, since in the latter case the fuel subset would be heated until it evaporated, however this, as well as a large number of further details, in particular of a constructive nature, can be designed quite differently from the exemplary embodiment shown, without departing from the content of the claims.

Reference symbol list:

1

Radial or Slinger combustion chamber, also called combustion chamber

2nd

Centrifugal compressors

2a

Compressor impeller

3rd

Axial direction

4th

Rotor shaft

4a

Interior of 4

4b

(flange-like) crossing part of 4

4c

Discharge pipe

5

Turbine part

5a

Turbine disc

6

air flow supplied to the combustion chamber, promoted by 2

6a

Leakage air

8th

Compressor back room

9

Vent hole (in 4b)

10th

(central) outlet opening (in 5a)

11

(central) bore in 2a, which receives 12

12th

Delivery pipe (for fuel, running in 2a)

13

Fuel injection tube

14

Centrifugal siphon

15

Distribution chamber (for fuel, in 4b)

16

Radial direction

17th

Supplier drilling (for fuel, in 4b)

19th

Central axis (of the small gas turbine)

20th

Distribution cone

21

Baffle plate

22

axial groove (s) in the edge of 21

23

Screw connection

33

first gap

34

second gap

35

Rolling bearing on the compressor part side

36

Rolling bearing on the turbine part side

37

Casing (of the small gas turbine)

38

Capillary tube

38a

Flow hole

39

Location hole (for 38 in 4b)

40

Blind hole

41

drilling

42

Bearing annulus

43

poetry

44

Warehouse back room

45

Working gas flow channel

Claims (4)

Small gas turbine with a radial or Slinger combustion chamber as well as with a radial compressor (2) or diagonal compressor upstream of the radial or Slinger combustion chamber and with a compressor that runs in the axial direction (3) and is supported by at least one roller bearing (36) Turbine part (5) connected to the rotor shaft (4), the fuel passing through a delivery pipe (12) provided in the impeller (2a) of the radial compressor / diagonal compressor into a crossing part (4b) of the rotor shaft (4) located in the region of the combustion chamber (1) near the compressor and is supplied to the combustion chamber (1) via supply bores (17) running essentially in the radial direction (16) thereof,
and wherein a centrifugal siphon (14) through which the fuel flows is provided in or upstream of the intersection part (es) (4b) upstream of the supply bores (17),
characterized in that a capillary tube (38) branches off from the centrifugal siphon (14) on the combustion chamber side and thereby upstream of the supply bores (17), via which a partial fuel quantity is fed to the roller bearing (36) on the turbine part side. Small gas turbine according to claim 1, wherein the centrifugal siphon (14) is formed by a baffle plate (21) which adjoins the end of the delivery pipe (12) with the formation of a first gap space (33) extending outward in the radial direction (16), the baffle plate Fuel emerging from the delivery pipe (12) passes via this first gap space (33) into the area of at least one axial groove (22) made in the edge of the baffle plate (21) and via this on the side of the baffle plate (1) facing the combustion chamber (1). 21) is guided inwards again radially inwards into a distributor chamber (15) from which the supply bores (17) branch off, via a second gap space (34),
characterized in that the capillary tube (38) branches off from the second gap space (34) upstream of the distribution chamber (15). Small gas turbine according to claim 1 or 2,
characterized in that the capillary tube (38) runs in the rotor shaft (4) and opens in front of a bore (41) which penetrates the wall of the rotor shaft (4) and through which the partial fuel quantity reaches a bearing annular space (42) which the roller bearing (36) is arranged. Small gas turbine according to one of the preceding claims,
characterized in that the bearing annular space (42) is delimited to the side of the combustion chamber (1) by means of a seal (43), in particular designed as a labyrinth seal, which allows a slight passage of combustion chamber gas.

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