EP1283326B1 - Cooling of a turbine vane - Google Patents

Description

The invention relates to a turbine blade with a extending along a blade axis, mainly in its longitudinal direction by a cooling medium can be flowed through Airfoil.

Gas turbines are used in many areas to drive generators or used by work machines. It is the Energy content of a fuel for generating a rotational movement used a turbine shaft. The fuel will burned in a combustion chamber, being used by an air compressor compressed air is supplied. That in the combustion chamber produced by the combustion of the fuel, under high Pressure and high temperature working medium is doing via a turbine downstream of the combustion unit led, where it relaxes work.

To generate the rotational movement of the turbine shaft are in this case a number of usually in blade groups or blade rows of combined blades arranged, via a momentum transfer from the flow medium drive the turbine shaft. For guiding the flow medium in the turbine unit are also usually between adjacent blade rows with the turbine housing connected Leitschaufelreihen arranged. The turbine blades, in particular the guide vanes, usually have for suitable guidance of the working medium along a blade axis extended on, on the end for attachment of the turbine blade at the respective Carrier body a transverse to the blade axis erstrekkende Platform can be formed.

In the design of such gas turbines is in addition to achievable performance usually a particularly high efficiency a design goal. An increase in efficiency can be basically for thermodynamic reasons by increasing the outlet temperature, with the working medium from the combustion chamber off and in the Turbine unit flows. Therefore, temperatures of about 1200 ° C to 1300 ° C for such gas turbines sought and also achieved.

At such high temperatures of the working medium, however the components and components exposed to this high exposed to thermal loads. Nevertheless, with high reliability a comparatively long life of the affected Ensuring components is usually one Cooling of the affected components, in particular of Runners and / or vanes of the turbine unit, provided. The turbine blades are therefore usually designed coolable, in particular, an effective and reliable Cooling seen in the direction of flow of the working medium first rows of blades should be ensured. For cooling usually has the respective turbine blade one integrated into the airfoil or the blade profile Cooling medium channel, from which a cooling medium targeted in particular the thermally loaded zones of the turbine blade can be supplied.

As a cooling medium usually cooling air is used. This usually becomes the respective turbine blade in the way of an open cooling over an integrated one Cooling medium channel supplied. After exiting the turbine blade the cooling air is in the process with that in the turbine unit mixed working medium. The design performance However, such a cooled gas turbine is limited, especially because of the limited mechanical Resilience of individual components of the gas turbine one further increase in performance usually only can be reached by an increased fuel supply. These in turn requires a comparatively increased need for Cooling medium for cooling the turbine blades, in turn Losses in the available compressor mass flow means. These Losses can only be tolerated to a limited extent become. Moreover, it can also be used in gas turbines with regard to a required safety will be necessary, a mixing from flowing out of the turbine blade cooling medium and prevent the turbine unit flowing through the working medium.

From the published patent application DE 1601553 is a hollow wing-shaped Guide vane with a gas turbine engine insert known. The insert is designed so that a minimal flow of a fluid medium for a sufficient Cooling can be adjusted. This is the use spaced from the inner wall of the airfoil and extends along the longitudinal extent of the vane wedge-shaped. In use, cooling air outlet openings are provided, which the inside of the upstream leading edge are opposite.

The invention is therefore based on the object, a turbine blade of the type mentioned above for which Relatively simple means a reliable and effective closed cooling, especially using of cooling air as the cooling medium is enabled.

This object is achieved by the features of independent claim 1.

The invention is based on the consideration that a effective cooling for a turbine blade in particular with a flat action on the wall to be cooled of the blade with cooling medium can be achieved. It was recognized that such a surface admission of a targeted Supply of the cooling medium to the wall and a Guide the cooling medium along this required. This is achievable by a separate inflow and outflow channel is provided for cooling medium. Starting from this Division of the cooling medium channel is the admission the wall of the airfoil to be cooled in the way that the cooling medium in the course of his crossing of the Flowed in the outflow channel in a transverse direction becomes.

The guidance of the cooling medium mainly in the longitudinal direction of the blade allows compliance particularly short and thus loss-reduced flow paths for the Coolant flow. This main flow direction is changed only in the area in a transverse direction in which a such change of targeted and effective cooling is used. Inevitable flow losses are thus at a low level held. Also an admission of the airfoil with a comparatively large amount of cooling medium not hampered by restrictions in the flow path. From particular advantage is that a large cooling capacity in one comparatively small portion of the flow path of the Coolant, namely in the course of its in the transverse direction to the airfoil arranged Wegabschnitts, when crossing is supplied selectively from the inflow into the outflow.

The inflow channel can be selected, especially thermally highly loaded areas of the turbine blade assigned Make outlet openings for cooling medium to transfer into have the discharge channel. For this purpose, the inflow passage in about evenly distributed over its length to be cooled Inner wall of the airfoil facing outlet openings for the cooling medium. This way is special simply a flat cooling of the blade can be achieved. The cooling can be done by means of a so-called impingement cooling take place, one having the outlet openings Wall of the inflow channel serves as an impact cooling wall, with the on she encounters impinging cooling medium in intensive contact and then via the outlet openings for passage into the Outflow channel can be derived.

The passage of the cooling medium to the inner wall to be cooled of the airfoil takes place in the transverse direction purposeful and enhancing the cooling effect by the or - with several internal walls to be cooled - each to be cooled Inner wall of the airfoil each with the cooling medium conductive, provided transversely to the blade axis ribs is. These ribs also have an additional cooling rib effect result and thus further improve the cooling.

To ensure a uniform flow of the cooling medium and the space available in the turbine bucket take advantage of targeted, takes the free cross-section the inflow channel in the blade in the longitudinal direction preferably from. Thus, the fact is taken into account, that in the course of the inflow channel an increasing part of Cooling medium has already left the inflow and in the Outflow channel has passed. Especially with an over the length of the airfoil uniform, surface contact with cooling medium it is for a simple construction the turbine blade particularly advantageous if the free cross-section of the inflow channel in the airfoil in its Linear decreases linearly. In this case, the inflow channel For example, very simple from flat metal plates be formed. For the sake of a steady, free Volume flow of cooling medium through the turbine blade through takes the free cross section of the discharge channel in the blade in the longitudinal direction corresponding to the decrease of free cross section of the inflow channel to. To the extent, in the cooling medium leaves the inflow, is the free cross-section the Anströmkanals reduced and at the same time in corresponding dimension of the free cross section of the outflow channel increased for outflowing cooling medium. This can be done in the Course of the outflow additionally in these trespassing Cooling medium without hindrance be removed quickly.

A very simple construction of inflow and / or outflow channel for example, from flat plates results when the inflow and / or the outflow channel parallel to the longitudinal direction of the airfoil and perpendicular to the to be cooled Inner wall of the airfoil according to an advantageous Training has a triangular cross-section.

Since usually not all walls of the airfoil of the Turbine blade exposed to same thermal loads are, it may be sufficient, only one inflow to the Cooling of a thermally stressed wall to provide in the turbine blade. In particular, however, if both the pressure and the suction side of the turbine blade must be cooled, it is advantageous, a second inflow for cooling medium for cooling a further inner wall to provide the airfoil, based on the Blade axis arranged symmetrically to the first inflow channel is. As opposed to the inner walls to be cooled are arranged, the first and the second inflow channel open preferably in a common outflow channel for Cooling medium. The outflow channel, for example, low in a central region of the airfoil.

Preferably, the inflow channel is at its one entrance surface for cooling medium remote from the end and / or the discharge channel facing away from its one exit surface for cooling medium Start closed, creating a simple construction and a trouble-free supply and discharge of the cooling medium to the and is enabled by the turbine blade.

For example, at a transversely to the blade axis extending platform - in particular for connecting the turbine blades on a turbine housing - having turbine blades, where due to high thermal stress However, a cooling of the platform is desired, but it can be favorable to deviate from the above-described construction principle: An advantage is a turbine blade, in which at the Airfoil at the Kühlmediumabströmseite a transversely formed to the blade axis platform is formed when the platform one connected to the inflow, with Has cooling medium acted upon cooling chamber. To this Way is the inflow, the cooling medium to be cooled Inner wall of the airfoil feeds, the design of the Turbine blade considerably simpler at the same time as a feed channel used by cooling medium to the cooling chamber of the platform. - Of equal advantage is a turbine blade, at the on the blade at the Kühlmediumanströmseite an integrally formed transversely to the blade axis extending platform is that one connected to the outflow, with Has cooling medium acted upon cooling chamber. It can the cooling medium used for cooling the platform directly be removed from the blade, without consuming Return flow should be provided or that the Danger of mixing with cooling medium could exist, the provided for cooling the inner wall of the airfoil is. The effective cooling of the airfoil is thus not endangered.

For a particularly low effort in the production of Turbine blade is the or each cooling chamber advantageously poured into the respective platform and outwards completed by a cover plate. Thus, the cooling chamber be produced directly during the casting of the turbine blade, so that a post-processing of the casting is not required is. For reliable completion of the respective cooling chamber To the outside is only the attachment of the respective Cover plate required.

A particularly reliable cooling of the respective structural parts with cooling medium can be reached by means of an impingement cooling. For this purpose, the or each cooling chamber is advantageous in one Floor area arranged at a distance from the chamber floor Impact cooling plate provided. The impingement cooling plate is in the essentially formed as a perforated plate, wherein on the Impact cooling plate impacting cooling medium with this in particular intensive contact occurs and then on the perforation can be derived. For a reliable cooling medium discharge is in a further advantageous embodiment a more limited by the chamber bottom and the baffle plate Outflow space of the cooling chamber connected to the outflow channel. Accordingly, for a reliable supply of cooling medium to the cooling chamber according to another advantageous embodiment through the cover plate and the baffle cooling plate limited inflow space of the cooling chamber connected to the inflow channel.

The turbine blade is preferably as a guide vane for a gas turbine, in particular for a stationary gas turbine, educated.

The advantages achieved by the invention are in particular in that by providing an inflow and an outflow channel in the turbine blade, the cooling medium when crossing from the inflow into the outflow channel in a transverse direction is guided along the inside of the airfoil, whereby allows a two-dimensional loading of the airfoil is and results in a particularly effective cooling. The Turbine blade is doing with relatively little effort producible, in particular, it is important that Inlet and outlet channel as simple inserts in the airfoil can be mounted, can be formed. In addition is in a comparatively simple way, inclusion of concepts a closed cooling with air as the cooling medium allows.

Figur 1

eine Turbinenschaufel in einem Teil-Längsschnitt,

Figur 2

einen Querschnitt durch die Turbinenschaufel nach Figur 1,

Figur 3

eine andere Turbinenschaufel in teilgeschnittener perspektivischer Ansicht und

Figur 4

eine weitere Turbinenschaufel in einem Längsschnitt.

An embodiment of the invention will be explained in more detail with reference to a drawing. Show:

FIG. 1

a turbine blade in a partial longitudinal section,

FIG. 2

a cross section through the turbine blade of Figure 1,

FIG. 3

another turbine blade in a partially sectioned perspective view and

FIG. 4

another turbine blade in a longitudinal section.

Identical parts are given the same reference numerals in all figures Mistake.

The turbine blade 1 according to FIG. 1 has an airfoil 2, which extends along a blade axis 4. The Airfoil 2 is for the appropriate influence of a in a dedicated turbine unit flowing working medium arched and / or curved.

The turbine blade 1 is used as a guide vane for one here not shown gas turbine and in the manner of a closed Cooling as coolable with cooling air as the cooling medium Turbine blade formed. For this purpose, the blade 2 mainly in its longitudinal direction L of cooling medium K. permeable, wherein the cooling medium K from a Kühlmediumanströmseite AS forth in the blade 2 and enters a Kühlmediumabströmseite BS from this again emerges.

In the airfoil 2 are substantially over the entire Length 1 a inflow channel 6, in the cooling medium K of the Kühlmediumanströmseite AS ago can come forth, and a discharge channel 8 for cooling medium K out. About the outflow channel 8, the cooling medium, the airfoil 2 on the Kühlmediumabströmseite Leave BS again. The inflow channel 6 is on the one hand by a flat, closed wall 10, the diagonal in the airfoil 2, and on the other hand a flat, outlet openings 12 for cooling medium K having Wall 14 limited; the closed wall 10 and the outlet openings 12 having wall 14 can of sheet metal plates be formed. The outlet openings 12, the in distributed approximately uniformly over the length 1 of the inflow channel 6 are, having wall 14 is parallel to a to be cooled Inner wall 16 of the airfoil 2 arranged so that between this inner wall 16 and the aforementioned wall 14th the inflow channel 6, an overflow channel 18 is formed.

In the overflow 18 is from the inflow duct 6 in the Outflow channel 8 passing cooling medium K in a transverse direction Q of the airfoil 2 on the inner wall to be cooled 16 of the airfoil 2 along. At this inner wall 16 are in the transverse direction Q of the airfoil 2 extending Ridges 20 are arranged, which are the flow direction of the override cooling medium K and also in addition serve as cooling fins for the airfoil 2.

After the cooling medium on the inner wall 16 of the airfoil 2 this has flowed along cooling, it enters the Outflow channel 8 a. The outflow channel 8 is limited on the one hand from the plane, closed wall 10, diagonally in the blade 2 extends and the inflow channel 6 of the Outflow channel 8 separates, and on the other hand by an inner wall 22 of the airfoil 2, which is the inner wall to be cooled 16 opposite.

The arrangement is chosen such that the free cross section 40 of the inflow channel 6 in the blade 2 in the longitudinal direction thereof L decreases linearly. At the same time increases with the measure this decrease in the free cross section 52 of the outflow channel. 8 in the blade 2 in the longitudinal direction L to. Furthermore Both the inflow 6 and the outflow channel 8 are parallel to the longitudinal direction L of the airfoil 2 and perpendicular to the inner wall 16 to be cooled a triangular cross-section on.

In particular, the overflow of the cooling medium K from the inflow channel 6 in the discharge channel 8 illustrates Figure 2, the a cross section along line II - II through the turbine blade 1 represents FIG. In addition to the one to be cooled Inner wall 16 of the airfoil 2 facing, the outlet openings 12 having wall 14 and the opposite of this, closed wall 10 has the inflow channel. 6 two connecting the latter walls 10, 14, further Walls 24, 26, so that the inflow duct 6 except one Entry surface and the outlet openings 12 are closed is. In this case, the other walls 24, 26 each of a sheet metal plate are formed.

In the longitudinal direction L of the airfoil 2 in the inflow passage 6 inflowing cooling medium K leaves this channel on the Outlet openings 12 and then encounters the inner wall 16 of the airfoil 2. This results in an impact cooling effect, which is further enhanced by the fact that the cooling medium K - additionally guided by ribs 20 - on the inner wall 16 of the airfoil 2 in the transverse direction Q is guided along and thereby by overflow channels 18, 28, 30 enters the discharge channel 8; while the cooling medium flows K around at least part of the inflow channel 6 around and passes then into the discharge channel 8, through which it turns in Flows longitudinally of the airfoil 2. Due to the the inner wall 16 of the airfoil 2 arranged ribs 20 results in a cooling effect enhancing cooling fin effect.

Another turbine blade 1 with an airfoil 2 shows in a partially cut, perspective view Figure 3. The airfoil 2 here has a first and a second Anströmkanal 6, 32 for cooling medium K, wherein the inflow channels 6, 32 relative to the blade axis 4 symmetrical to each other are arranged and the airfoil 2 in his Pull longitudinal direction L through a length 1. Cooling medium K occurs at the Kühlmediumanströmseite AS of the airfoil. 2 in the inflow channels 6, 32, flows through the airfoil 2 in its longitudinal direction L in both inflow channels 6, 32nd and leaves it via outlet openings 12, which are shown in FIG. 3 for the sake of clarity, only in the first inflow channel 6 are shown. Then the cooling medium K flows in one perpendicular to the longitudinal direction L of the airfoil 2 extending Transverse Q each on an inner wall to be cooled 16, 36 of the airfoil 2 along. These inner walls 16, 36 are the outlet openings 12 of the inflow channels 6, 32 arranged opposite and with - in Figure 3 of For clarity, only on the first to be cooled inner wall 16 - ribs 20 for guiding the cooling medium K provided. The flow along the to be cooled inner walls 16, 36 takes place during a transition of the cooling medium K from the inflow channels 6, 32 in a common outflow channel 8 for cooling medium K, the center between the Anströmkanälen 6, 32 is arranged. Via the outflow channel 8 becomes the cooling medium K in the longitudinal direction L of the airfoil 2 whose Kühlmediumabströmseite BS supplied.

Point to the Kühlmediumanströmseite AS of the airfoil the inflow channels 6, 32 each have an entry surface 34, 38 forming free cross section of equal size. This free cross-section of the inflow channels 6, 32 increases in the airfoil 2 in the longitudinal direction L from linear, so that at half length 1/2 of the free cross section 40, 42 also respectively is halved when the inflow channels 6, 32 at their the Inlet surface 34, 38 for cooling medium K opposite end 44, 46 have no free cross-section. That means at the same time that the inflow channels at each of this end 44, 46th are closed.

By contrast, the discharge channel 8 is at its one of a formed free cross section exit surface 48 for cooling medium K facing away beginning 50 closed and has no there free cross section on. The free cross section of the outflow channel 8 in the blade 2 takes in the longitudinal direction L corresponding to the decrease of the free cross section of the Anströmkanäle 6, 32 to. Therefore, the free cross section 52 the outflow channel 8 at half the length 1/2 of the airfoil 2 an area which is the sum of the free cross sections 40, 42 of the inflow channels 6, 32 corresponds at this point. In order to is a free outflow of the cooling medium K ensured.

In addition to a longitudinal direction L extending recess 54, in the inflow channels 6, 32 and the outflow channel 8 are arranged are, the airfoil 2 more in the longitudinal direction L. extending recesses 56, 58, 60 on. The latter Recesses 56, 58, 60, which are shown in Figure 3 as cavities can also be with corresponding inlet and outlet channels be provided for cooling medium and for cooling the turbine blade 1 are used.

Another turbine blade 1, in particular a vane for a gas turbine, with a two re a blade axis 4 symmetrically arranged inflow channels 6, 32 for cooling medium K having blade 2 shows Figure 4 in a longitudinal section. To the blade 2 is on a Kühlmediumanströmseite AS a transverse to the Blade axis 4 extending first platform 62 integrally formed, which forms a head plate. On a Kühlmediumabströmseite BS is a transverse to the blade axis 4 extending, a foot plate forming second platform 64 is formed. cooling medium K enters the Kühlmediumanströmseite AS in the first Platform 62 and in one of a cover 66 shielded central, with the inflow channels 6, 32 connected Area of the airfoil 2 a. A cooling chamber 68 of the first Platform 62 is connected to the outflow channel 8, so that already used for cooling the first platform 62 Coolant K through the discharge channel 8 immediately can be led out of the blade 2.

The the inflow channels 6, 32 supplied cooling medium K leaves These inflow channels 6, 32 either through outlet openings 12, 70 in to be cooled inner walls 16, 36 of the airfoil 2 facing walls 14, 72 or through at the respective Entry surface for cooling medium K opposite ends of the Anströmkanäle 6, 32 provided transitions 74, 76 to a Cooling chamber 78 of the second platform 64. The cooling medium K, the passes through the outlet openings 12, 70, is in a transverse direction Q at the to be cooled, ribs 20, 80 having Inner walls 16, 36 of the airfoil 2 along out, then enters the discharge channel 8 and leaves over this the blade 2 at the Kühlmediumabströmseite BS.

The cooling chambers 68, 78 of the platforms 62, 64 are in this cast in and outwards in each case via a cover plate 82, 84 completed. In addition, the cooling chambers 68, 78 each in its bottom region with a distance to the chamber bottom 86, 88 arranged impingement cooling plate 90, 92 provided. In the cooling chamber 68 of the first platform 62 is a discharge space 94 present through the chamber floor 86 and the Impact cooling plate 90 is limited and connected to the discharge channel 8 is. On the other hand, the cooling chamber 78 of the second Platform 64 on a Anströmraum 96 through the cover plate 84 and the impingement cooling plate 92 is limited and to the Anströmkanäle 6, 32 is connected. This way you can the Anströmraum 96 are fed by the inflow channels 6, 32, through walls 10, 98 separated from the discharge channel 8 are.

Claims (15)

1. Turbine blade/vane (1), having a blade/vane aerofoil (2) which extends along a blade/vane axis (4) and through which cooling medium (K) can flow, mainly in the longitudinal direction of Turbine blade/vane (1), in which an incident flow duct (6) and an efflux duct (8) for cooling medium (K) are routed within the blade/vane aerofoil (2), essentially over its complete length (1), and the incident flow duct (6) and the efflux duct (8) are connected together on the cooling medium side in such a way that cooling medium (K) passing from the incident flow duct (6) into the efflux duct (8) is conducted in a transverse direction (Q) along a wall inner surface (16), which has to be cooled, of the blade/vane aerofoil (2), the incident flow duct (6) having outlet openings (12) for the cooling medium (K), which are approximately uniformly distributed over the length of Turbine blade/vane and face towards the wall inner surface (16), which has to be cooled, of the blade/vane aerofoil (2),
   characterized in that an area exposure of the wall inner surface (16) to cooling medium can be achieved by a plurality of outlet openings (12) distributed in the transverse direction (Q), and
   the or each wall inner surface (16), which has to be cooled, of the blade/vane aerofoil (2) is respectively provided with ribs (20, 80), which are arranged transversely to the blade/vane axis (4) and guide the cooling medium (K).
2. Turbine blade/vane according to Claim 1, in which the free cross section (40) of the incident flow duct (6) in the blade/vane aerofoil (2) decreases in the longitudinal direction (L) of the latter.
3. Turbine blade/vane according to Claim 2, in which the free cross section (40) of the incident flow duct (6) in the blade/vane aerofoil (2) decreases linearly in the longitudinal direction (L) of the latter.
4. Turbine blade/vane according to Claim 2 or 3, in which the free cross section (52) of the efflux duct (8) in the blade/vane aerofoil (2) increases in the longitudinal direction (L) of the latter to correspond with the decrease in the free cross section (40) of the incident flow duct (6).
5. Turbine blade/vane according to one of the preceding claims, in which the incident flow duct (6) and/or the efflux duct (8) have a triangular cross section parallel to the longitudinal direction (L) of the blade/vane aerofoil (2) and at right angles to the wall inner surface (16), which has to be cooled, of the blade/vane aerofoil (2).
6. Turbine blade/vane according to one of the preceding claims, in which a second incident flow duct (32) for cooling medium (K) for cooling a further wall inner surface (36) of the blade/vane aerofoil (2) is arranged symmetrically, with respect to the blade/vane axis (4), relative to the first incident flow duct (6).
7. Turbine blade/vane according to Claim 6, in which the first incident flow duct (6) and the second incident flow duct (32) open into a common efflux duct (8) for cooling medium (K).
8. Turbine blade/vane according to one of the preceding claims, in which the incident flow duct (6, 32) is closed at its end (44, 46) remote from an inlet area (34, 38) for cooling medium (K) and/or the efflux duct (8) is closed at its beginning (50) remote from an outlet area (48) for cooling medium (K).
9. Turbine blade/vane according to one of the preceding claims, in which a platform (64), which extends transversely to the blade/vane axis (4), is formed on the blade/vane aerofoil (2) at its cooling medium efflux end (BS), which platform has a cooling chamber (78), which is joined to the incident flow duct (6, 32) and to which cooling medium (K) can be admitted.
10. Turbine blade/vane according to one of the preceding claims, in which a platform (62), which extends transversely to the blade/vane axis (4), is formed on the blade/vane aerofoil (2) at its cooling medium incident flow end (AS), which platform (62) has a cooling chamber (68), which is joined to the efflux duct (8) and to which cooling medium (K) can be admitted.
11. Turbine blade/vane according to Claim 9 or 10, in which the or each cooling chamber (68, 78) is cast into the respective platform (62, 64) and is closed towards the outside by means of a cover panel (82, 84).
12. Turbine blade/vane according to one of Claims 9 to 11, in which the or each cooling chamber (68, 78) is provided, in a floor area, with an impingement cooling panel (90, 92) arranged at a distance from the chamber floor (86, 88).
13. Turbine blade/vane according to Claim 12, in which an efflux space (94) of the cooling chamber (68), which is bounded by the chamber floor (86) and the impingement cooling panel (90), is joined to the efflux duct (8).
14. Turbine blade/vane according to Claim 12, in which an incident flow space (96) of the cooling chamber (78), which is bounded by the cover panel (84) and the impingement cooling panel (92), is joined to the incident flow duct (6, 32).
15. Turbine blade/vane according to one of the preceding claims, which is configured as a guide vane for a gas turbine.

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