Guide vane

Abstract

The invention relates to a guide vane (1) for a turbomachine, in particular for a stationary gas turbine, comprising an inner platform (2), an outer platform (3) and a blade (4) extending therebetween in a longitudinal direction (L) and having an outer wall (5) which defines a front leading edge (6), a rear trailing edge (7), a suction side (8) and a pressure side (9), wherein the blade (4) is provided with at least one meandering cavity (10) through which a cooling fluid is conducted during operation of the turbomachine, wherein the cavity (10) has cavity sections (13, 14, 15) which extend in the longitudinal direction (L) and are arranged adjacent to one another in a front-rear direction (X) and transition sections (16, 17) which connect these cavity sections (13, 14) to one another in a meandering manner at the ends, wherein inserts (18, 19) which extend in the longitudinal direction (L) are inserted into at least two directly adjacent cavity sections (13, 25, 14), which inserts give these cavity sections (13, 14) an annular cross section, and wherein the insert (19) arranged downstream has at least one cooling fluid deflection element (25) which projects outwards from the insert (19) in the direction of the outer platform (3).

Description

[0001] Description

[0002] Leitschauf el

[0003] The invention relates to a guide vane for a turbomachine, in particular for a stationary gas turbine, comprising an inner platform, an outer platform and a blade extending longitudinally between them with an outer wall defining a leading edge, a trailing edge, a suction side and a pressure side, wherein the blade is provided with at least one meandering cavity through which a cooling fluid is guided during operation of the turbomachine, wherein the cavity has longitudinally extending cavity sections arranged adjacent to each other in a front-to-back direction and transition sections connecting these at their ends in a meandering manner, wherein longitudinally extending inserts are inserted into at least two immediately adjacent cavity sections, giving these cavity sections an annular cross-section.

[0004] Turbomachinery, for example in the form of stationary gas turbines, is known in the art in a wide variety of configurations. It serves to convert the thermal energy and flow energy of a hot gas into mechanical rotational energy. In the turbine section of the turbomachine, the hot gas is guided through an annular flow channel, internally bounded by a rotor. The turbine section has several turbine stages in the direction of flow, each comprising a stationary guide vane assembly and a rotor blade assembly attached to the rotor. The guide vanes projecting into the flow channel are designed to direct the hot gas flow at the most favorable angle possible onto the downstream rotor blades, which also project into the flow channel, in order to impart the greatest possible force to the rotor blades, thus setting the rotor in motion.The rotational energy of the rotor can then be converted into electrical energy, for example using a generator.

[0005] The thermodynamic efficiency of a gas turbine increases with rising turbine inlet temperature of the hot gas. However, the hot gas temperature is limited, among other things, by the thermal stress capacity of the components arranged in the flow channel. One way to achieve the highest possible hot gas inlet temperature is to cool thermally stressed components, such as the guide vanes. The aim is to keep the required cooling fluid mass flow rate as low as possible.

[0006] Guide vanes typically comprise an inner platform located near the rotor, an outer platform, and a longitudinally extending blade extending between them. The blade has a leading edge, a trailing edge, a suction side, and a pressure side, where "front" and "back" refer to the flow direction of the hot gas stream during operation of the turbomachine. In many known guide vane designs, the blade is provided with a meandering cavity through which a cooling fluid is passed to cool the guide vane during operation. The cavity comprises several longitudinally extending cavity sections arranged adjacent to one another in a front-back direction, and transition sections that meander at their ends to connect these cavity sections.In some designs, longitudinally extending inserts are placed in at least two immediately adjacent cavity sections, giving these sections an annular cross-section. To allow the inserts to be inserted into the cavities from one side, the cavities must be relatively straight. During operation, a cooling fluid flows through the cavity, passing through the individual sections and being deflected by 180° within the transition sections. These deflections, combined with the straight shape of the cavities, result in significant variations in the local flow velocities of the cooling fluid within the downstream cavity section, which is undesirable for achieving uniform cooling of the blade.

[0007] Starting from this state of the art, one object of the present invention is to create a guide vane of the type mentioned above with an improved design.

[0008] To solve this problem, the present invention provides a guide vane for a turbomachine, in particular for a stationary gas turbine, comprising an inner platform, an outer platform and a blade extending longitudinally between them, the blade having an outer wall defining a leading edge, a trailing edge, a suction side and a pressure side, wherein the blade is provided with at least one meandering cavity through which a cooling fluid is guided during operation of the turbomachine, wherein the cavity has longitudinally extending cavity sections arranged adjacent to one another in a front-to-back direction and transition sections connecting these at their ends in a meandering manner, wherein longitudinally extending inserts are inserted into at least two immediately adjacent cavity sections.which give these cavity sections an annular cross-section, and wherein the downstream insert has at least one cooling fluid deflection element projecting outwards from the insert into the transition section arranged between these two cavity sections. During operation of the guide vane, such a cooling fluid deflection element projecting into the transition section divides the cooling fluid flow into several partial flows at the moment of its deflection and directs these partial flows in predetermined directions. In this way, the variance of local flow velocities can be significantly reduced, thereby optimizing the cooling of the blade. According to the invention, the at least one cooling fluid deflection element is formed on the insert so that the cooling fluid deflection element does not negatively affect the manufacturing and mechanical stress of the blade.

[0009] Preferably, at least one cooling fluid deflection element is located on the suction side and pressure side of the insert.

[0010] Advantageously, at least one cooling fluid deflection element, viewed in longitudinal section of the blade, has a crescent-shaped cross-section, the concave side of which points towards the incoming cooling fluid flow. Such a shape for the at least one cooling fluid deflection element has proven to be particularly effective and low-loss.

[0011] Preferably, the downstream insert has elongated cooling fluid guide vanes projecting on both the suction and pressure sides. These vanes are arranged downstream of the cooling fluid deflection elements and extend essentially in the longitudinal direction. Such cooling fluid guide vanes direct the cooling fluid flowing through the cavity section towards the outer wall of the cavity section, which also contributes to improved cooling.

[0012] Advantageously, the cooling fluid guides extend over a length, measured longitudinally, that corresponds to 1 / 2 to 3 / 4 of the insert's length. Particularly good cooling results were achieved with this length.

[0013] Preferably, in order to keep flow losses low, the cooling fluid guide vanes, when considering the blade in longitudinal section, have an arc-shaped cross-section, the concave side of which points in the direction of the incoming cooling fluid flow.

[0014] According to one embodiment of the present invention, the inserts have protruding spacers on the suction side and pressure side, which ensure proper positioning of the inserts within the corresponding cavity sections.

[0015] Preferably, the inserts are connected to each other via a plate-shaped connecting section, which advantageously closes the cavity.

[0016] Further features and advantages of the present invention will become clear from the following description with reference to the accompanying drawing. Therein is

[0017] Figure 1 is a schematic perspective view of a guide vane according to an embodiment of the present invention, Figure 2 is an enlarged transparent schematic partial view of a blade of the guide vane shown in Figure 1,

[0018] Figure 3 shows a partial sectional view along line III-III in Figure 2.

[0019] Figure 4 shows a schematic side view of two inserts of the paddle blade shown in Figure 2, connected to each other via a plate-shaped connecting bridge.

[0020] Figure 5 is a schematic diagram of an area shown in Figure

[0021] 2 arrangement shown, and

[0022] Figure 6 is a schematic diagram showing an alternative design of the area shown in Figure 5.

[0023] Figure 1 shows a guide vane 1 according to an embodiment of the invention, which is in particular a guide vane of a stationary gas turbine not shown in detail here. The guide vane

[0024] I comprises an inner platform 2, an outer platform

[0025] 3 and a blade 4 extending between these in a longitudinal direction L, with an outer wall 5 defining a leading edge 6, a trailing edge 7, a suction side 8, and a pressure side 9. The blade 4, as shown in Figures 2 and 3, has a cavity 10 and a channel.

[0026] II provided, through which a cooling fluid is passed during the operation of the turbomachine, as indicated by arrows 12 in Figure 2.

[0027] The cavity 10 is designed in a meandering shape and in this case has three cavity sections 13, 14 and 15 extending in the longitudinal direction L and arranged adjacent to each other in a front-back direction X, and two transition sections 16 and 17 connecting these cavity sections 13, 14 and 15 at their ends in a meandering manner.

[0028] Inserts 18 and 19, extending longitudinally in the direction L and preferably designed as hollow bodies, are inserted into the two front cavity sections 13 and 14. These inserts give the cavity sections 13 and 14 an annular cross-section and narrow the cross-section through which the cooling fluid flows. The inserts 18 and 19, which are manufactured, for example, by means of 3D printing, are each provided with spacers 20 projecting towards the outer wall 5 of the blade 4 on the suction and pressure sides, respectively. These spacers ensure proper positioning of the inserts 18 and 19 within the cavity sections 13 and 14. The surfaces of the inserts 18 and 19 are essentially flat.The inner surfaces of the outer wall 5 are provided in the area of ​​the two front cavity sections 13 and 14 with linear projections 21 that extend obliquely to the front-to-back direction X and obliquely to the longitudinal direction L and are spaced apart from one another. In the illustrated embodiment, as best shown in Figure 4, the inserts 18 and 19 are connected to each other via a plate-shaped connecting section 22, which seals the two cavity sections 13 and 14 at the top. They have recesses 23, 24 facing each other in the transition section 16, which enlarge the transition section. The shape and size of the recesses 23, 24 are selected such that the cooling fluid can flow freely through the transition section 16. The downstream insert 19 comprises at least one cooling fluid deflection element 25 projecting on the suction side and pressure side, which extends outwards into its recess 24.The cooling fluid deflection element 25, viewed in longitudinal section of the blade 4, has a crescent-shaped cross-section, the concave side 26 of which points in the direction of the incoming cooling fluid flow. The downstream insert 19 further comprises, in this case, elongated cooling fluid guide vanes 27 projecting on the suction and pressure sides, which are arranged downstream of the cooling fluid deflection elements 25 and extend substantially in the longitudinal direction L. The cooling fluid guide vanes 27 preferably extend over a length in the longitudinal direction L that corresponds in particular to 1 / 2 to 3 / 4 of the length of the insert 19 and, in this case, is approximately 2 / 3 of the length of the insert 19. Viewed in longitudinal section of the blade 4, the cooling fluid guide vanes 27 have an arcuate cross-section, the concave side 28 of which points in the direction of the incoming cooling fluid flow.The rearmost cavity section 15 of the meandering cavity 10 is provided with a plurality of turbulators 29 extending between the suction side 8 and the pressure side 9, as well as with a plurality of cooling fluid outlet openings 30 arranged along the outflow edge 7.

[0029] The channel 11 extends along the leading edge 6 and is fluidically connected to the rear cavity section 15 of the cavity 10.

[0030] During operation, as shown in Figures 2 and 5, a cooling fluid is introduced from below into the front cavity section 13 of the meandering cavity 10, flows upwards to the first transition section 16, is deflected there by 180°, and is thereby divided into several partial flows due to the cooling fluid deflection element 25 projecting from the rear insert 18 into the recess 24 or into the transition section 16. These partial flows are directed into the front, middle, and rear regions of the middle cavity section 14 and then guided to the second transition section 17. The cooling fluid guide vanes 27 ensure that the respective partial flows traverse all regions of the middle cavity section 14 at the most uniform velocity possible and that no separation zones occur.After being deflected again in the second transition section 17, the cooling fluid then enters the rear cavity section 15 of the meandering cavity 10 and exits the blade 4 through the cooling fluid outlet openings 30. Another cooling fluid flow, fed into the blade 4 from below, is introduced into the channel 11, flows through it, and is then guided, as shown in Figure 2, through the outer platform 3 into the rear cavity section 15 of the cavity 10, from which it exits through the cooling fluid outlet openings 30.

[0031] In the embodiment described above, the transition section 16 is largely formed by the two recesses 23 and 24 of the inserts 18 and 19. Alternatively, the transition section 16 can also be formed, as schematically shown in Figure 6, by a dome-shaped cover 331, which covers the cavity sections 13 and 14 of the cavity 10, leaving a gap between the inserts 18 and 19 on the one hand and the cover 33 on the other.

[0032] Although the invention has been illustrated and described in detail by the preferred embodiment, the invention is not limited by the disclosed examples and other variations can be derived by the person skilled in the art without leaving the scope of protection of the invention.

[0033] Regardless of the grammatical gender of a particular term, persons with male, female or other gender identities are included.

Claims

Patent claims 1. Guide vane (1) for a turbomachine, in particular for a stationary gas turbine, comprising an inner platform (2), an outer platform (3) and a blade (4) extending between them in a longitudinal direction (L) with an outer wall (5) defining a leading edge (6), a trailing edge (7), a suction side (8) and a pressure side (9), wherein the blade (4) is provided with at least one meandering cavity (10) through which a cooling fluid is guided during operation of the turbomachine, wherein the cavity (10) has longitudinally extending (L) cavity sections (13, 14, 15) arranged adjacent to each other in a front-to-back direction (X) and transition sections (16, 17) connecting these at their ends in a meandering manner, wherein at least two immediately adjacent cavity sections (13, 14) extend longitudinally (L) extending operations (18, 19) are deployed,which give these cavity sections (13, 14) an annular cross-section, and wherein the downstream insert (19) has at least one cooling fluid deflection element (25) which projects outwards from the insert (19) into the transition section (16) arranged between these two cavity sections (13, 14).

2. Guide vane (1) according to claim 1, characterized in that the at least one cooling fluid deflection element (25) projects from the insert (19) on the suction side and pressure side.

3. Guide vane (1) according to claim 1 or 2, characterized in that the at least one cooling fluid deflection element ment (25) , considering the blade (4) in longitudinal section, has a crescent-shaped cross-section, the concave side (26) of which points in the direction of the incoming cooling fluid flow.

4. Guide vane (1) according to one of the preceding claims, characterized in that the downstream arranged insert (19) has elongated cooling fluid guide webs (27) projecting on the suction side and pressure side, which are arranged downstream of the at least one cooling fluid deflection element (25) and extend substantially in the longitudinal direction (L).

5. Guide vane (1) according to claim 4, characterized in that the cooling fluid guide vanes (27) extend over a length measured in the longitudinal direction (L) which corresponds to 1 / 2 to 3 / 4 of the length of the insert (19).

6. Guide vane (1) according to claim 4 or 5, characterized in that the cooling fluid guide vanes (27) have an arc-shaped cross-section when considering the blade (4) in longitudinal section, the concave side (28) of which points in the direction of the incoming cooling fluid flow.

7. Guide vane (1) according to one of the preceding claims, characterized in that the inserts (18, 19) have spacers (20) projecting on the suction side and pressure side.

8. Guide vane (1) according to one of the preceding claims, characterized in that the inserts (18, 19) are connected to each other via a plate-shaped connecting section (22), and that the inserts (18, 9) have recesses (23, ) in the transition section that point towards each other. 24) having at least one cooling fluid deflection element (25) projecting outwards into the recess (24) of the downstream insert (19).

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