Guide vane for a turbomachine

Abstract

A guide vane for a turbomachine, having a blade airfoil and at least one platform, to which the blade airfoil is connected. A cooling channel system is provided for cooling the platform and the blade airfoil. The platform has, on the side thereof facing the airfoil, at least one sealing lip for sealing to a rotating system of the turbomachine. At least one cooling channel extends through the sealing lip, which cooling channel forms part of the cooling channel system.

Claims

1. A guide vane for a turbomachine, comprising: a vane blade and a platform to which the vane blade is connected, a cooling duct system for cooling the platform and the vane blade, and at least one seal lip, wherein the at least one seal lip projects radially inwardly from a side of the platform that faces away from the vane blade for sealing in relation to a rotating system of the turbomachine, wherein at least one cooling duct which forms part of the cooling duct system extends through the at least one seal lip, wherein the cooling duct system comprises a plurality of cooling ducts which extend through the at least one seal lip in at least a substantially radial direction, exit openings of said plurality of cooling ducts being disposed in a free end of the at least one seal lip that is a radially inward end of the seal lip facing away from the vane blade, and wherein the plurality of cooling ducts are circumferentially spaced apart from one another.

2. The guide vane as claimed in claim 1, wherein the at least one seal lip is disposed in a peripheral region of the platform that is forward or rearward in the axial flow direction, and from the side of the platform that faces away from the vane blade projects in at least a substantially radial manner such that said at least one seal lip defines a terminating face of the platform that extends so as to be largely parallel to the radial direction.

3. The guide vane as claimed in claim 1, wherein at least one connecting duct which connects the plurality of cooling ducts to one another and forms part of the cooling duct system is provided so as to be spaced apart from the free end of the at least one seal lip.

4. The guide vane as claimed in claim 1, wherein the platform is assembled from a platform base part and at least one platform attachment part that is connected, welded, or soldered/brazed, to said platform base part, wherein the at least one cooling duct and/or further parts of the cooling duct system is/are at least in part defined by the at least one platform attachment part.

5. The guide vane as claimed in claim 4, wherein at least one groove, or a groove produced by casting technology, which in order for at least the at least one cooling duct to be defined is covered by a platform attachment part in the form of a plate, or a metal plate, is provided in the platform base part.

6. The guide vane as claimed in claim 5, wherein the platform attachment part is provided in the form of a U-shaped profile plate which is disposed between the two seal lips in such a manner that the opposite legs of said U-shaped profile plate bear in a planar manner on the two seal lips and cover the at least one groove.

7. The guide vane as claimed in claim 5, wherein the platform attachment part is provided in the form of a U-shaped profile plate, the first leg thereof bearing in a planar manner on a first of the two seal lips in order for the at least one groove provided therein to be covered, and the second leg thereof being connected, welded, or soldered/brazed, to a leg of a further platform attachment part in the form of a termination plate in order for the second of the two seal lips to be defined by the two connected legs.

8. The guide vane as claimed in claim 5, wherein the platform attachment part is provided in the form of an integral profile plate having a U-shaped portion, the first leg thereof bearing in a planar manner on a first of the two seal lips in order for the at least one groove provided therein to be covered, and the second leg thereof defining the second of the two seal lips, and a termination plate portion that adjoins said integral profile plate.

9. The guide vane as claimed in claim 4, wherein the platform attachment part is produced in an additive manner, or by selective laser melting—SLM, and completely defines at least the at least one cooling duct.

10. The guide vane as claimed in claim 9, wherein the platform attachment part defines two seal lips that are connected by way of a brace and a termination plate that is connected to the two seal lips.

11. The guide vane as claimed in claim 9, wherein at least one turbulence element is incorporated in the at least one cooling duct.

12. The guide vane as claimed in claim 4, wherein the platform base part and/or the at least one platform attachment part are/is produced from a super alloy, or a nickel-based super alloy.

13. The guide vane as claimed in claim 4, wherein the platform base part and the at least one platform attachment part are produced from the same material, or from a super alloy, or a nickel-based super alloy.

14. The guide vane as claimed in claim 1, wherein the platform on the side thereof that faces away from the vane blade comprises two directly adjacent seal lips which extend so as to be at least substantially mutually parallel and spaced apart.

15. The guide vane as claimed in claim 1, wherein the plurality of cooling ducts are at least substantially mutually parallel.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further features and advantages of the present invention will become evident by means of the description hereunder of four embodiments of a guide vane for a turbomachine according to the present invention, with reference to the appended drawing. In the drawing:

(2) FIG. 1 shows a schematic lateral view of a guide vane according to a first embodiment of the present invention;

(3) FIG. 2 shows a schematic view of part of the platform of the guide vane illustrated in FIG. 1, seen from obliquely below;

(4) FIG. 3 shows a schematic view of part of the platform of the guide vane illustrated in FIG. 1, having visible cooling and connecting ducts, seen from obliquely below;

(5) FIG. 4 shows a schematic enlarged view of the region of the platform marked by B in FIG. 3;

(6) FIG. 5 shows a schematic lateral view of part of the platform of the guide vane illustrated in FIG. 1, in a partially sectional view;

(7) FIG. 6 shows a schematic lateral view of part of the platform of a guide vane according to a second embodiment of the present invention, in a partially sectional view;

(8) FIG. 7 shows a schematic lateral view of part of the platform of a guide vane according to a third embodiment of the present invention, in a partially sectional view; and

(9) FIG. 8 shows a schematic lateral view of part of the platform of a guide vane according to a fourth embodiment of the present invention, in a partially sectional view.

DETAILED DESCRIPTION OF INVENTION

(10) FIGS. 1 to 5 show schematic views of a guide vane 1 for a turbomachine according to a first embodiment of the present invention. The guide vane 1 herein comprises a vane blade 2 and a platform 3 to which the vane blade 2 is connected. The platform 3 is assembled from a platform base part 4 and platform attachment parts 5 in the form of a U-shaped metal profile plate 5a having two opposite legs 6, 7, and in the form of a termination plate 5b, said plates being connected to the platform base part 4 by means of welding. The platform base part 4, for sealing in relation to a rotating system of the turbomachine, at the peripheral region thereof that is rearward in the axial flow direction A comprises two directly adjacent seal lips 8, 9 that extend so as to be mutually parallel and spaced apart and radially project from that side of the platform 3 that faces away from the blade. The seal lips 8, 9 are thus radially inward pointing sealing partners of the seal assembly which as communicating sealing partners comprises a friction face (not illustrated) or a seal lip of a likewise design that however points outward. The communicating sealing partner is disposed on the rotor or is part of a rotor blade. The rearmost seal lip 9 in the axial flow direction A defines a terminating face 10 of the platform 3.

(11) Grooves 11 produced by casting technology are provided in the platform base part 4, in particular in the rearmost seal lip 9 in the axial flow direction A. The U-shaped metal profile plate 5a is disposed between the two seal lips 8, 9 in such a manner that the opposite legs 6, 7 of the latter bear in a planar manner on the seal lips 8, 9, on account of which the grooves 11 are covered by the metal profile plate 5a. Accordingly, cooling ducts 12 which form part of a cooling duct system for cooling the guide vane 1 are defined by the platform base part 4 as well as by the metal profile plate 5a. On account of the configuration of the platform 3 in two parts, in particular thin seal lips 8, 9 can be actively cooled in an efficient manner.

(12) In the embodiment described here, six cooling ducts 12 are configured in the seal lip 9, the exit openings of said cooling ducts 12 being disposed in a radially inward pointing free end 13 of the seal lip 9. From there, the cooling ducts 12, in each case proceeding from the rearmost seal lip 9 in the axial flow direction A, extend through the seal lip 9 in a slightly oblique manner in relation to the radial direction R, thus in a substantially radial direction R, and so as to be mutually parallel.

(13) The cooling duct system moreover comprises a connecting duct 14 which extends in the circumferential direction of the platform 3 and is provided so as to be spaced apart from the free end 13 of the seal lip 9, the cooling ducts 12 opening into said connecting duct 14 such that said cooling ducts 12 are connected to one another. The connecting duct 14 that extends approximately in the circumferential direction of the platform 3 is connected to a collection duct 16 by way of a plurality of connecting ducts 15 that extend in the axial flow direction A. The collection duct 16 is at least in part defined by a further platform attachment part 5 in the form of a termination plate 5b which is connected to the platform base part 4 by means of welding. The connecting ducts 15 and the collection duct 16 likewise form part of the cooling duct system.

(14) In that the cooling duct system does not only have ducts within a primary portion of the platform 3 but also in the seal lip 8 an ideally uniform cooling of the platform 3 is achieved, and large temperature variations within the material of the platform 3 are avoided.

(15) In the case of the afore-described embodiment, the platform base part 4 as well as the platform attachment parts 5, or 5a and 5b, respectively, are produced from the same nickel-based super alloy.

(16) In operation, the cooling fluid is supplied to the cooling duct system of the guide vane, said cooling fluid subsequently flowing through the collection duct 16 and the connecting duct 14 and thereafter being able to flow through the cooling ducts 12 in order for the seal lip 8 to be cooled. By virtue of the exit openings disposed in the free end 13, the cooling fluid upon leaving the guide vane finally contributes toward improving the seal assembly between the stator and the rotor.

(17) The second embodiment of a guide vane 1 according to the invention, shown in FIG. 6, corresponds substantially to the first embodiment. The single point of differentiation lies in that the platform base part 4 in the case of the second embodiment at the rear peripheral region thereof in the axial flow direction A comprises only the first seal lip 8 of the two seal lips 8, 9. As is already the case in the first embodiment, the first leg 6 of the U-shaped metal profile plate 5a also in the second embodiment bears in a planar manner on the first seal lip 8 and is connected to the latter by means of welding. However, in the case of the second embodiment, the termination plate 5b also has a leg 17 which by means of welding is connected to the second leg 7 of the U-shaped metal profile plate 5a in order for the second seal lip 9 of the two seal lips 8, 9 to be defined. Grooves 11 which are covered by the U-shaped metal profile plate 5a and the termination plate 5b in order for the six cooling ducts 12 and the connecting ducts 14, 15 to be partially defined are cast in the platform base part 4, in particular the first seal lip 8. Moreover, the termination plate 5b conjointly with the platform base part 4 defines the collection duct 16.

(18) FIG. 7 shows a third embodiment of a guide vane 1 according to the invention, in which the platform 3 is assembled from a platform base part 4 and exactly one platform attachment part 5, which is produced in an additive manner by means of selective laser melting and is connected by means of welding to the platform base part 4. The platform base part 4 in the case of the third embodiment does not comprise any seal lip 8, 9 at all. Instead, the platform attachment part 5 defines two seal lips 8, 9 that are connected by a brace 18, and a termination plate 5b of the platform 3 that is connected to the seal lips 8, 9.

(19) Moreover, the platform attachment part 5 completely defines the cooling ducts 12 within the seal lip 8, said cooling ducts 12 having been mentioned in the context of the two preceding embodiments, as well as the connecting duct 14 that extends in the circumferential direction of the platform 3. The cooling ducts 12 configured by means of an additive production method are very small, this being particularly advantageous when very narrow seal lips are to be actively cooled. Turbulence elements which for the sake of clarity are not shown in FIG. 7 are incorporated in the cooling ducts 12. Said turbulence elements enable the heat transfer to be precisely adapted to the respective stress of the platform 3.

(20) In the case of the third embodiment, the connecting ducts 15, that extend in the axial flow direction A and have likewise already been mentioned in the context of the two preceding embodiments, are cast in the platform base part 4 and, like the collection duct 16, are partially defined by the platform attachment part 5.

(21) As can be seen in FIG. 8, the platform attachment part 5 is welded to the platform base part 4 in such a manner that the ducts 12, 14 of the platform attachment part 5 are fluidically connected to the further ducts 15, 16.

(22) The fourth embodiment of a guide vane 1 according to the invention, shown in FIG. 8, corresponds substantially to the third embodiment. The single point of differentiation lies in that the connecting ducts 15 that extend in the axial flow direction A in the case of the fourth embodiment are bored into the platform base part 4 and are therefore completely defined by the platform base part 4.

(23) While the invention in detail has been illustrated and described in more detail by way of the exemplary embodiments, the invention is not limited by the disclosed examples, and other variations can be derived therefrom by the person skilled in the art without departing from the scope of protection of the invention.