Turbine vane arrangement

Abstract

A guide vane arrangement of a gas turbine and a method of manufacturing a guide vane arrangement of a gas turbine are provided herein. The guide vane arrangement includes a first guide vane device including a first radially inner platform and a first number of first airfoils, and a second guide vane device including a second radially inner platform and a second number of second airfoils. The first guide vane device and the second guide vane device are arranged along a circumferential direction of the turbine, wherein the first number of the first airfoils differs to the second number of the second airfoils. The first guide vane device is designed with a higher heat resistance than the second guide vane device.

Claims

1. A guide vane arrangement for a gas turbine, the guide vane arrangement comprising: a first guide vane device comprising a first platform and a first number of first airfoils, wherein the first number of first airfoils is attached to the first platform, and a second guide vane device comprising a second platform and a second number of second airfoils, wherein the second number of second airfoils is attached to the second platform, wherein the first guide vane device and the second guide vane device are arranged along a circumferential direction of the turbine, wherein the first number of the first airfoils differs to the second number of the second airfoils, and wherein the first guide vane device is designed with a higher heat resistance than the second guide vane device, wherein the first guide vane device is coated with a first temperature resistant coating, wherein the second guide vane device is coated with a second temperature resistant coating, and wherein a first thickness of the first temperature resistant coating is larger than a second thickness of the second temperature resistant coating; and further comprising: a further first guide vane device comprising a further first number of further first airfoils, and wherein the further first guide vane device is arranged between the first guide vane device and the second guide vane device along the circumferential direction of the turbine, wherein the further first number of further first airfoils differs from the second number of second airfoils, and wherein the further first guide vane device is designed with a higher heat resistance than the second guide vane device.

2. The guide vane arrangement according to claim 1, wherein the first number of the first airfoils is smaller than the second number of the second airfoils.

3. The guide vane arrangement according to claim 2, wherein the first number of the first airfoils is one and the second number of the second airfoils is two or higher.

4. The guide vane arrangement according to claim 1, wherein the first guide vane device comprises a first cooling duct through which a cooling fluid is flowable.

5. The guide vane arrangement according to claim 4, wherein the second guide vane device comprises a second cooling duct through which a further cooling fluid is flowable.

6. The guide vane arrangement according to claim 5, wherein the first cooling duct comprises a larger hydraulic diameter than the second cooling duct.

7. The guide vane arrangement according to claim 4, wherein the first cooling duct comprises a first aperture for injecting or draining the cooling fluid in or out of the first cooling duct, and wherein the second cooling duct comprises a second aperture for injecting or draining the cooling fluid in or out of the second cooling duct, wherein the first aperture is larger than the second aperture such that a higher mass flow of cooling fluid is flowable in or out of the first cooling duct than in or out of the second cooling duct.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The aspects defined above and further aspects of the present invention are apparent from the examples of embodiment to be described hereinafter and are explained with reference to the examples of embodiment. Aspects of the invention will be described in more detail hereinafter with reference to examples of embodiment but to which the invention is not limited.

(2) FIG. 1 shows a schematical view of a guide vane arrangement according to an exemplary embodiment of the present invention; and

(3) FIG. 2 shows a perspective view of the exemplary embodiment of a guide vane arrangement as shown in FIG. 1 according to an exemplary embodiment of the present invention.

DETAILED DESCRIPTION

(4) The illustrations in the drawings are schematic. It is noted that in different figures similar or identical elements are provided with the same reference signs.

(5) FIG. 1 shows a guide vane arrangement 100 for a gas turbine. A guide vane arrangement 100 includes a first guide vane device 110 including a first number of first airfoils 111 and a second guide vane device 120 including a second number of second airfoils 121. The first guide vane device 110 and the second guide vane device 120 are arranged one after another, e.g. detachably coupled together, along a circumferential direction 102 of the turbine. The first number of the first airfoils 111 differs to the second number of the second airfoils 121. The first guide vane device 110 is designed with a higher heat resistance than the second guide vane device 120.

(6) In the exemplary embodiment shown in FIG. 1, the first guide vane device 110 includes one airfoil 111 (guide vane) and is a so-called single vane nozzle. The second guide vane device 120 includes in the exemplary embodiment shown in FIG. 1 two second airfoils 121 (guide vanes) and is a so-called double vane nozzle.

(7) As shown in FIG. 1, the turbine includes a rotary axis 101. A direction around the rotary axis 101 is denoted as the circumferential direction 102. Along the circumferential direction 102, different temperature areas T1, T2 exists during operation of the turbine. The first temperature area T1 is for example hotter than the second temperature area T2. The different temperature areas T1, T2 form a heat distribution along the circumferential direction 102. This varying heat distribution is caused by the arrangement of several combustion chambers, i.e. combustion cans, along the circumferential direction 102 of the turbine.

(8) As can be taken from FIG. 1, in the hotter first temperature area T1 the first guide vane device 110 and, depending on the circumferential size of the first temperature area T1, a plurality of further first guide vane devices 110′ are arranged. In the second temperature areas T2, second guide vane devices 120 and further second guide vane devices 120′ are arranged.

(9) The first guide vane device 110 includes a first shroud with a first platform 112. The first platform 112 shown in FIG. 1 is a radially inner platform. In FIG. 1, a radially inner vane carrier 130 is shown. The first guide vane device 110 is mounted by its first inner platform 112 e.g. detachably to the inner vane carrier 130. The airfoil 111 is mounted to a radially outer surface of the first radially inner platform 112 of the first guide vane device 110 and extends along a radially outer direction.

(10) The first guide vane device 111 may further include a first cooling duct 113 which runs along the first platform 112 and through the airfoil 111.

(11) Accordingly, the second guide vane device 120 includes a second inner shroud with a second inner platform 122. In contrast to the first inner platform 112 of the first guide vane device 110, two or more second airfoils 121 are mounted to one common second inner platform 122. The second guide vane device 120 may include a second cooling duct 123 which may run along the respective second airfoils 121 and along the second inner platform 122.

(12) The first guide vane devices 110, 110′ have a higher heat resistance than the second guide vane devices 120, 120′. The higher heat resistance of the first guide vane devices 110, 110′ may be adjusted by using more cooling fluid or by using respective material compositions or temperature resistant coatings.

(13) The arrangement and the pattern of the first guide vane de-vices 110, 110′ and the second guide vane devices 120, 120′ along the circumferential direction 102 may be determined on the basis of the circumferential location of the hotter first temperature areas T1 and the colder second temperature areas T2. The heat distribution of the first temperature areas T1 and the second temperature areas T2 along the circumferential direction 102 may be determined on the basis of data of a heat distribution of a respective turbine during operation. The data may be achieved by simulations, by a computer model and/or by experimental tests.

(14) FIG. 2 shows an exemplary embodiment of the present invention as shown in FIG. 1. Additionally, in FIG. 2, a radially outer vane carrier 200 is shown. As can be taken from FIG. 2, the first guide vane devices 110, 110′ and the second guide vane devices 120, 120′ are mounted and coupled detachably by its respective platforms 112, 122 to the inner vane carrier 130 and the outer vane carrier 200. Hence, along the circumferential direction 102, a variety of first and second guide vane devices 110, 110′, 120, 120′ are arranged dependent on the heat distribution of a guide vane stage of a turbine.

(15) In FIG. 1 and in FIG. 2 circumferential sections of a guide vane stage of a turbine are shown. However, the guide vane stage forms generally a circumferentially closed, ring-shaped stage. The respective vane carriers 130, 200 may have a semi circle profile or a full circle profile.

(16) It is particularly advantageous to have the first guide vane device 110 with one single airfoil 111 (guide vane), i.e. it is implemented as a single vane nozzle. That allows an easy application of a coating from all sides, particularly by spraying, which may not be so easy for a double vane nozzle or a nozzle with even more vanes. Furthermore a single vane nozzle may be shorter in circumferential length compared to a double vane nozzle or a nozzle with even more vanes. This has the consequence that it results in less stress compared to a nozzle with a longer circumferential length.

(17) According to the previously said, the orientation and size of the vanes may be identical to all nozzles, independently whether provided via a single nozzle or a nozzle with a plurality of vanes. Alternatively, as the single nozzle may be provided in sections with higher temperature and possibly also with different fluid flow speed and fluid flow orientation, it is also possible to provide a different orientation of the vane of the single nozzle than the vanes of the other nozzles. Also the distance between two vanes can be adjusted by using single nozzles in comparison to nozzle with a plurality of vanes.

(18) It should be noted that the term “comprising” does not exclude other elements or steps and “a” or “an” does not exclude a plurality. Also elements described in association with different embodiments may be combined. It should also be noted that reference signs in the claims should not be construed as limiting the scope of the claims.