GAS TURBINE HAVING AXIAL THRUST PISTON AND RADIAL BEARING

Abstract

A gas turbine having an axially adjustable rotor, has the following components: at least one external compressor air bleed for bleeding compressor air; a control valve for adjusting the amount of compressor air bled via the at least one external compressor air bleed; an axial thrust piston that can be supplied with the compressor bleed air via a supply line in such a way that a different axial compensation thrust is applied to same when the amount of compressor bleed air is adjusted; and a radial bearing which cooperates with the axial thrust piston for bearing purposes, and which can also be directly or indirectly supplied with the compressor bleed air via the supply line.

Claims

1. A gas turbine having an axially adjustable rotor, comprising the following components: at least one external compressor bleed for extracting compressor air; a control valve for adjusting the quantity of compressor air which is extracted via the at least one external compressor bleed; an axial thrust piston which can be supplied with the extracted compressor air via a feed pipe in such a way that with adjustment of the quantity of compressor air a different axial compensating thrust is applied to this; a radial bearing at the end of the gas turbine which interacts with the axial thrust piston in a bearing-technological manner, and which can also be supplied directly or indirectly with the extracted compressor air via the feed pipe.

2. The gas turbine as claimed in claim 1, wherein the axial thrust piston and the radial bearing are interconnected in series with regard to the supply with compressor air.

3. The gas turbine as claimed in claim 1, wherein the axial thrust piston and the radial bearing are interconnected in parallel with regard to the supply with compressor air.

4. The gas turbine as claimed in claim 1, wherein provision is made for at least two external compressor bleeds for extracting compressor air at a different pressure level and both open into the feed pipe for the axial thrust piston and for the radial bearing.

5. The gas turbine as claimed in claim 1, further comprising: a cooling device, which enables cooling of the compressor air, which is connected into the feed pipe.

6. The gas turbine as claimed in claim 4, further comprising: an additional adjusting element that is connected into the feed pipe, which additional adjusting element enables the compressor air which is extracted from the at least two external compressor bleeds and is already intermixed to be adjusted with regard to its quantity.

7. The gas turbine as claimed in claim 1, further comprising: a pressure measuring device, which allows determination of the pressure level at which the compressor air is fed to the axial thrust piston, which is connected into the feed pipe.

8. The gas turbine as claimed in claim 1, wherein the axial piston and the radial bearing are in contact with each other in a bearing-technological manner in the region of a bearing surface for providing the rotor bearing.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In this case, in the drawing:

[0026] FIG. 1 shows a schematic side sectional view through a first embodiment of a gas turbine according to the invention;

[0027] FIG. 2 shows a schematic sectional view through a further embodiment of a gas turbine according to the invention.

DETAILED DESCRIPTION OF INVENTION

[0028] FIG. 1 shows a side sectional view through a first embodiment of the gas turbine 1 according to the invention which has a rotor 2 which is adjustable in the axial direction A with regard to an axial compensating thrust. During operation of the gas turbine 1, air is inducted via the intake duct 15, and is subsequently compressed in individual stages of the compressor.

[0029] After corresponding combustion with a fuel and downstream expansion in an expansion turbine, the working medium is discharged again from the gas turbine 1 via an exhaust gas diffuser 16 which is arranged in the region of the rear bearing support 17. The rotor 2 is equipped at the front end with a thrust bearing 8 which is designed for the purpose of absorbing the axial thrust forces, or to apply corresponding counterforces upon the rotor 2. At the rear end, the gas turbine has a radial bearing 11 which is sealed against an axial thrust piston 10 by means of seals 12. Both components, the radial bearing 11 and the axial thrust piston 10, interact in a bearing-technological manner by for example the axial thrust piston 10 being arranged on a bearing surface of the radial bearing 11 for bearing purposes.

[0030] If the gas turbine 1 is now operated in different operating states, a change of the axial thrust upon the rotor 2 in the axial direction A occurs. In this case, different forces are to be absorbed by the thrust bearing 8 or at relatively low partial load operating modes an axial thrust reversal may also occur. In such a case, the direction of the resulting axial thrust changes from initially the compressor to the expansion turbine to a direction which is oriented exactly opposite this. As a result of such an axial thrust reversal, undesirable vibrations of the rotor 2 can occur, as a result of which not only the thrust bearing 8 is negatively affected but the entire gas turbine 1 can be damaged.

[0031] In order to now expose the rotor 2 to the action of a suitable compensating force the present embodiment of the gas turbine 1 has three external compressor bleeds 3 via which compressor air can be extracted from individual plena of the compressor at different pressure levels P1, P2 and P3. The compressor air flows can be introduced into a feed pipe 5 and mixed. For suitable mixing of the individual flows suitable ejectors can be used for example (not shown in the present case). In order to be able to adjust the quantity of compressor air from the individual plena 7 during extraction the present invention has in each case a control valve 4 which is associated with the external bleeds 3 in each case. By means of these, the values of the extracted compressor air flows from the individual plena can be adjusted in a specific manner. The mixed flow of compressor air can also thermally interact with a cooling device 20 before feed to the axial thrust piston 10 and to the radial bearing 11, as a result of which the just mentioned components can be thermally conditioned. This is particularly advantageous if the extracted compressor air has a comparatively high temperature level, and therefore would be unsuitable to be in direct contact with the radial bearing 11.

[0032] In order to suitably adjust the overall flow of compressor air in the feed pipe 5, an adjusting element 6 is connected into the feed pipe 5 and allows the quantity of compressor air which is fed to the radial bearing 11 and to the axial thrust piston 10 to be again additionally adjusted.

[0033] The adjusting element 6 and the control valves 4 are suitably adjusted according to the embodiment by means of an adjusting unit 23 which in its turn can again take into account suitable measured values. The measured values can be delivered for example via a measuring device 21 in the region of the thrust bearing 8, which measured values are received for example as pressure or force (=thrust). In particular, for example the axial thrust on the thrust bearing can therefore be directly tracked. Also, the adjusting unit 23 can take into consideration the measured values of a pressure measuring device 30 which is attached in the region of the bearing support 17 of the gas turbine 1. The pressure measuring device 30 senses in this case the pressure which prevails in the compressor air duct and which is correlated directly with the pressure upon the axial thrust piston 10. The compressor air duct in the bearing support 17 is in this case part of the feed pipe 5. If the compressor air is directed onto the axial thrust piston 10, this transmits a compensating force (compensating thrust) to the rotor 2. The compressor air then flows via the seal 12 to the radial bearing 11 and seals this and additionally cools this, or is discharged from there for example into the environment.

[0034] FIG. 2 shows a further embodiment of the gas turbine 1 according to the invention, which differs from the embodiment depicted in FIG. 1 only to the effect that in the bearing support 17 there are now two separate fluid passages which are designed for the purpose of conducting the compressor air, which is introduced into the respective passages, to one of the components comprising axial thrust piston 10 and radial bearing 11 respectively. Both feed pipes are provided individually with an adjusting element 6 so that the two passages can be supplied in each case with different quantities of compressed air. After the compressed air has been transferred to the components, this can either not be mixed with full decoupling or can be intermixed again with partial decoupling. Therefore, it is possible for example that the compressor air which is fed to the axial thrust piston 10 is fed at least partially to the radial bearing. In this case, for example the compressor air would flow via the seal 12 to the radial bearing 11. It is also conceivable to design the seal 12 so that there is a largely fluid decoupling of both components, or so that the compressor air from the respective components makes its way into different discharge passages for discharging from the gas turbine.

[0035] Further embodiments are gathered from the dependent claims.