Axial-flow turbine stator blade

FIELD: mechanical engineering; axial-flow turbines.

SUBSTANCE: proposed blades of axial-flow turbine stator has channel expanding into cone to pass flow of gas through turbine. Blade is provided with flat at its root which is connected with stator housing with provision of tight fit and reliable locking of joint. Stator blade root is made in form of hollow profile with radially inner flat of blade root which is made to suit contour of channel to pass flow of gas through turbine and radially outer flat of blade root arranged at a distance inner flat from and made to suit contour of stator housing, and also side wall or two, mainly parallel, side walls. Outer flat is provided with at least one hole to accommodate corresponding attachment part by means of which said is secured on stator housing.

EFFECT: simplified fastening of blade to stator housing.

12 cl, 67 dwg

The present invention relates to the construction of the stator blades of the turbomachine. More specifically it relates to the design of the tail blades, providing a detachable connection between the body of the scapula, and the body of the stator of this machine by means of fasteners, preferably screws, which are screwed with ensuring a tight fit.

In the description of the patent RU 2038487 C1 revealed widespread type of attachment used to connect the blades of the stator with the stator housing multi-stage turbine. The stator within which is enclosed channel for passing a flow executed expanding on the cone consists of many separate parts. The inner shell of the stator has an annular recess, into engagement with which protrusions are provided on the tail blades, forming a reliable blocked the connection between the blade of the stator and stator housing. This solution causes some difficulties in production in the manufacture of the housing of the stator, arising in connection with the complicated design because of the numerous protrusions and recesses.

In order to avoid these shortcomings, apply a known technical solution, in which case the stator and the stator blade are interconnected by means of fixing screws /Avesta is a and others, "Design of aircraft engines". Military aviation engineering Academy. Zhukovsky, 1958, s/. The tail blades are equipped with this purpose, the extended area, made in the form of a plate. The blade is attached to the chassis using two screws. Compared to discussed here above technical solution, the proposal allows to simplify the design of the stator housing, which substantially reduced the cost of its production, because it becomes possible to renounce the use of complicated internal structure. When designing it is possible in this case to define a more narrow gap in the labyrinth seal, because this eliminates the need to provide appropriate clearance for technological consideration is required to provide between members in mutual engagement with each other by the protrusions and recesses running in the stator housing and the stator blade.

However, this solution has its downside, which is that for reliable fortified blades required to provide two bolts. Plate tail blades mounted on the stator housing so that one bolt is located before the body of the blades in the direction of flow through the turbine, and the other behind her body. To accommodate mounting Altov required to provide additional places, which leads, ultimately, to an undesirable increase in the overall length of the turbine. The difference in heat temperatures for the tail blades and the stator, resulting in the individual stages of the unsteady process, resulting in different thermal expansion materials. Consequently, in the material result in undesirable mechanical stresses within the zone, which is located in the area between the bolts. And finally, the whole tail blades as a whole, including its fasteners, exposed to the influence of hot gases formed during operation of the turbine, without any protection against such effects. This fact, on the one hand, increases the amount of heat transmitted to the stator, and with the other hand to the fact that in this case, on the surface of the corresponding zones of roughness cause disturbances in the flow through the channel.

The problem to which the present invention is directed, is to establish a stator blades, the design of which would provide a simple and reliable connection of it with the stator housing, but while avoiding the above disadvantages inherent in the technical solutions known from the existing level in this field of technology.

This task is solved in accordance with h is a worthwhile invention by designing the vanes of the stator, providing the signs, disclosed in paragraph 1 of the claims. In the dependent claims and options for its implementation, developing this invention provide particular advantages.

The basic idea of the present invention is to design the tail blades in the form of a hollow profile that contains two sites of the tail, which are located at some distance from one another, and the first of which, representing the internal in the radial direction of the pad is aligned with a tapered contour of the channel for passing a flow through the turbine, and the second representing the outside in the radial direction of the pad, in accordance with the contour of that part of the casing wall in which it is located. Two side walls located mutually opposite one relative to another, connect the ground of the tail blades between themselves, forming a closed cavity. Preferably, the outer area of the tail blades, fitted was a hole designed to accommodate a corresponding fastener, which is preferably the mounting bolt for attachment of the vanes of the stator to the wall of the stator housing.

A closed cavity is formed between the pads and the side walls of the tail blades, provide Alicia places necessary for the placement of the respective fasteners that will be discussed in detail herein below explanation.

The surface of the outer plate of the tail blades are equipped with made in her recesses. When placing it next to the body of the stator are formed as a result of this additional cavity, which even more complicates the heat transfer. In an alternate implementation, or in addition, the inner wall of the stator housing may also have corresponding indentations.

In one alternative arrangement according to the present invention, the outer area of the tail blades is not a part that is executed in one piece with the tail blades, and is a removable part that is attached to the tail blades. In this case, the tail blades formed only broadened the inner area, which is turned into the body of the scapula and is made in the form of a plate, and two walls that are oriented in the radial direction, which are situated opposite one relative to another, and the ends of which are bent inward at right angles. Ledges made thus used as contact edges in contact with the outer plate.

In another alternative embodiment according to the present invention, Bo the new walls are mutually interconnected by means of two partitions, thanks to the two side walls together with the above two partitions, the internal space of the tail blades, the outer pad and the cylindrical surface of the stator form a cavity. In this cases, if the side walls and partitions shall be sealed to the cylindrical surface of the stator, and this node will be pulled by means of a screw connection, then this node can be ensured sufficiently sealed connection.

In this case, there may be provided a flow of cooling gas from any possible value of the second mass flow rate on the flow inside the specified cavity through the corresponding channel made in the body of the stator, and through the channel made in the outside area of the tail blades, without any this concern about overly large losses associated with leakage of the specified gas in the channel for passing a flow through the turbine. In this case, can also be done one channel passing through the outer area of the tail blades, and through the stator housing, and which is intended to be for the release of the cooling gas from the cavity.

In the third alternative embodiment according to the present invention, the bearing surface of each of the vanes at different radial at which ownah and joined with different cylindrical surfaces of the stator housing; in this case, the two bearing surfaces of two adjacent relative to each other of the blades are located on the same cylindrical surface of the stator housing.

This arrangement of bearing pads for blades, provides the opportunity to reduce the heating of the wall of the tail blades due to the conclusion of this wall from the hot zone, correlated with the channel for passing a flow through the turbine, as well as to reduce the heating of the respective end walls of the stator housing, paired with the specified wall of the tail blades.

In the fourth alternative embodiment according to the present invention, it is envisaged to arrange the side walls in a direction parallel to the longitudinal centerline of the stator, providing the seal bearing surfaces corresponding to the cylindrical surface and the end surface of the stator housing. The ends of the inner platform of the tail blades is also adjacent to the aforementioned surfaces of the stator housing. In this case, the corresponding fastener is inclined relative to the cylindrical surface and the end surface of the stator, and aimed it in his direction in such a way as to ensure the simultaneous pressing of the aforementioned bearing surfaces of the stator housing. In this case, IU the remote end surface of the stator, its cylindrical internal surface area of the tail blades and the two walls of the tail is formed sufficiently densified cavity isolated from the hot gases passing through the channel for passing a flow of gases through the turbine.

With this design is the possibility of cooling the inner walls of this cavity by means of the cooling gas with any second mass flow rate by the flow rate without any this concern about overly large losses associated with leakage specified cooling gas channel for passing a flow through the turbine. In this case, the exhaust channel that is designed to release the cooling gas from the cavity, can also be done in the stator housing. With this design the cooling of the specified cavity in the tail blades and even the internal cavity /if applicable/ profile blades occurs without any loss of the cooling gas, and thus there is, therefore, possible to achieve a corresponding increase of efficiency of the installation.

An important advantage of this variant implementation of the present invention is also the possibility of mounting the blades without the use of any sealing means between these areas and other parts and tail blades, because the proposed construction of the connections between the relevant part of the tail blades and the stator housing provides a virtually complete protection of the inner surface of the stator against exposure to hot gases that are in the path, which directs the flow of gases through the turbine.

The advantages of the design of the tail blades, made in accordance with the present invention, include, in particular, that the heat transferred to the stator from the channel designed to pass flow through the turbine, greatly reduced. Gas-filled cavity that is enclosed inside a hollow profile that restricts the passage of heat. Playground tail blades, which is based directly on the stator housing, exposed to less thermal stress. This helps to reduce heat conduction through the contact surface and through the corresponding fastener. Overall, as a result, the temperature of the stator becomes lower. Placement of appropriate fasteners or parts in the specified cavity provides, in addition, also, and protect these parts against direct exposure to the hot gases formed during operation of the turbine, which is also, and this is nemilov who the author is, increases reliability of the connection and, therefore, more secure. As in the case of the use of this technical solution corresponding fastener does not require for their placement of any additional space on both the front and rear body shoulder, the length of this particular site the tail blades in the axial direction is limited by the size defined by the body of the scapula. Thus, the present invention does not suffer from this drawback, as the increasing size of turbines along the length of inherent turbines with fixed stator blades with screws, if you compare them with the turbine stator blades which are held by means of a connection made by using the respective guide elements.

Moreover, the areas of the tail blades and fasteners do not have any impact on the flow in the main channel of the turbine.

And finally, there is a real opportunity to provide intentional supply of the cooling medium in this cavity, thus providing additional protection of the stator and corresponding fasteners from thermal stresses.

On the accompanying drawings shows very approximately in schematic form many different embodiments of the present invention. N what these drawings are reproduced only those features of the claimed design, which are necessary for understanding the present invention. The same structural elements, or those elements that correspond to one another are indicated on these drawings the same number of items. In these drawings:

figure 1 is a longitudinal section drawn through the tool is intended for fastening the stator vanes and carried out in accordance with the present invention;

figure 2 is a transverse cross-section, carried out along the line a-a shown in figure 1;

figure 3 is a longitudinal section of an alternative implementation of the present invention;

figure 4 is a transverse cross-section, carried out along the line a-a shown in figure 1, but built for another alternative implementation of the present invention;

figure 5 is a longitudinal section, built for a third alternative implementation of the present invention, and showing the tool is intended for fastening the stator blades;

figure 6 is a longitudinal section, built for the fourth alternative implementation of the present invention;

figure 7 is a transverse cross-section, carried out along the line B-B, showing the TES in figure 6.

The system of the blades shown in figure 1, located contains alternating rows of blades 14 of the impeller and stator blades 3, which are located within the channel 19, designed to pass flow through the turbine and executed expanding on the cone, and the specified channel is limited by the stator housing 1. The blades 14, which are fixed on the impeller of the turbine /not shown/, with corresponding elements 15 design, located at the vertices of these blades and forming the outer rim. With its upper side these design elements 15 forming the rim have sealing ribs 16, which are parallel to the direction of rotation of the impeller and its motion is almost in contact with the sealing strips 17, mounted on thermal screen 12, which is connected to the stator housing 1.

The housing 1 of the stator extending on the cone, has a design speed type, containing a number of cylindrical sections 2, the diameter of which increases with the transition from one segment to another. These cylindrical sections 2 correspond with the radial and the axial length of the individual rows of blades 3 and 14. Each of these sections 2 is provided with appropriate priority or spatula 3 stator or heat shield 12, and thus about the course, essentially continuous inner contour of the conical channel. Tail blades 3 of the stator forms a hollow profile with an inner radial direction pad 4 tail blades and the outer in the radial direction of the pad 5 of the tail blades, interconnected parallel side walls 6 and 7, passing in a transverse direction relative to the direction of flow. Interior in the radial direction of the platform 4 has a slope that corresponds to the taper of the channel 19, designed to pass flow through the turbine. Thus, situated on the back side in the flow direction of the side wall 6, usually shorter than the side wall 7, so the cavity 18, which is formed in each row of blades of the stator, has a more or less distinct trapezoidal, or approximately triangular shape of its cross section. Site 4 tail blade tightly abut one another, together in a continuous, around a closed wall of the channel in each row of blades 3, as shown in figure 2. Outside in the radial direction of the pad 5 of the tail blades is supported by a cylindrical section 2 of the housing 1 of the stator. The recesses 11, performed on the surface of the platform 5 and/or on the surface of the stator housing 1, to reduce the amount of transferred heat. In the building is 1 of the stator and the pad 5 is made coaxially relative to each other through holes of the fixing bolt 9. The body of the bolt, which is passed through the stator housing 1 with its outer side, is inside cavity 18 that is enclosed in the hollow profile, where it threaded nut 10 is screwed. The term "screw-nut" 10 in this context should not be understood strictly nut in the narrow sense of the word. For example, it can also be done in this case in the form of a paste, forming a single unit with the specified area of the tail blades having a through threaded hole. When you are tightening the bolts 9, 10, connect the blades 3 of the stator housing 1 of the stator, providing the tight fit and reliable lock connection. Apart from recording it with the mounting bolt 9, the blade 3 is held through a reliable locking it relative to the body 1 of the stator in the area of the contact surface 8 in contact with each other. Protected location inside the cavity 18 means that the body of the bolt 9 and the threaded nut 10 largely withdrawn from under the influence of gases formed during operation of the turbine. At the same time these items are not likely to adversely affect the conditions created in the flow channel 19. Inner wall of the channel in this case is essentially a smooth contour. The cooling medium may odevatisia inside cavity 18 via the inlet channels 23, made in the stator housing 1, and the inlet channels 24, made in outer space 5 of the tail blades.

Variant implementation of the present invention, is shown in figure 3, differs from the construction shown in figure 1, the fact that Playground 5 no longer is here an integral element composing the one with the tail blades, and is manufactured separately from the tail and runs as an independent element of the design that fits in the profile of the tail during Assembly. This alternative implementation of the present invention has certain advantages, manifested particularly noticeable in the production process, and in particular, when this feature designs complemented by the use of blades with internal cooling. This feature allows to simplify the process of casting and installation of such blades.

In this case, the outer ends of the side walls 6 and 7 are bent inward at right angles, to form the contact surfaces 20, 21, lying in the same plane and in contact with the pad 5, which is made in the form of a plate which is inserted inside. In this case, between the stator housing 1 and 5 of the tail blades, a gap 22, which reduces the heat transfer, and the value of which depends on the thickness stenocat contact surfaces 20 and 21. Then during the Assembly process into a hollow profile of the tail blades is inserted into the outer space 5, or if we consider this operation from the point of view of kinematics in reverse order hollow profile is placed on the platform 5, which provide sufficient freedom of relative displacement is connected with the fastening bolts 9. Playground 5 tail blades can be mounted inside of the hollow profile, using for this purpose the respective dowel pin 13.

In the embodiment of the present invention, is shown in figure 4, the tail blades 3 has such a construction that requires the presence of the cross-beams 25 and 26 connecting the side walls 6 and 7 of the tail blades /1/ with one another adjacent to the inner space 4 of the tail blades. Thus, bordered cavity 31, which is thus formed between the two side walls 6 and 7, two crossbars 25 and 26, the inner space 4 of the tail blades and the surface of the cylindrical section 2 of the stator housing. By providing a snug fit of the side walls 6 and 7 and the cross bars 25 and 26 to the surface of the specified cylindrical section 2 of the stator, and through the contraction of the resulting node by means of a threaded connection located on the platform 5 and consisting of a bolt 9 and a threaded resp is rste 27, may be this site sufficiently in sealed connection. This allows cooling of the walls of the cavity 31 is practically without any loss of the cooling medium. To ensure the flow of this cooling medium inside the cavity 31, provides for the implementation of the inlet channels 23 in the stator housing 1 and the respective inlet channels 24 in the space 5. Furthermore, the presence of the respective channels 29 and 30 are designed to release the cooling medium.

In yet another embodiment of the present invention, is shown in figure 5, the tail blades 3 has such a construction that provides for the implementation of load-bearing surfaces 32 and 33 at different radial levels. Each of these surfaces on the same blade, paired with different cylindrical surfaces of the individual sections of the stator housing. In addition, as the bearing surface 33 of the blade 3 and the bearing surface 32 of the vanes 34 are located on the same cylindrical surface of the corresponding section of the stator housing. This allows us to derive the wall 35 of the tail blades and opposite it the wall of the housing 1 of the stator from the hot zone formed in the channel 19, is designed to pass the flow of gases through the turbine, allowing obespechivayushchee the heating of these walls.

In the following embodiment of the present invention, is shown in figure 6, the tail blades 3 has such a construction in which the side walls 6 and 7 /7/ are parallel to the longitudinal centerline of the stator 1. When this bearing surfaces 37 and 38 of the side walls 6 and 7 are bonded simultaneously to the corresponding cylindrical surface 39 and to the end surface 40 of the housing 1 of the stator. In addition, the internal space 4 of the tail blades is also adjacent to the aforementioned surfaces of the corresponding section of the stator housing at the contact surfaces 36 and 28. Thus, the walls 6 and 7 in this respect, together with the wall of the inner platform 4 tail blades cylindrical surface 39 and an end surface 40, form a sufficiently compacted cavity 31, which is almost completely separated from the hot gases passing through the channel 19, intended for passing a flow of gases through the turbine. Corresponding fastener 9 can be located in this case, the proximity of the line of intersection of the cylindrical surface 39 and the end surface 40 of the stator housing 1 and is inclined at an angle to the end surface 40 that enables the simultaneous pressing of the aforementioned bearing surfaces 37 and 38, and the contact surfaces 36 and 28 to the surfaces 39 and 40 of the stator housing. Threaded on the opening 27 under this fastening element is located directly in the outer space 5 of the tail blades. In this embodiment, the present invention also provides the ability to perform the inlet port 23 and outlet port 30 in the stator housing 1, intended respectively for supply and discharge of the cooling medium, providing cooling the inner surfaces of the walls of the stator and the relevant parts of the tail blades. In this case, no observed loss of cooling medium from the cavity 31, seeping into the channel 19, which is designed to pass the flow of gases through the turbine.

It goes without saying that the present invention is not focused on only those variants of its implementation, which are discussed herein above the description. In particular, the specialist in the art should be obvious from the description of this invention that are possible to make various changes in the design of the tail blades, made in accordance with the present invention, for an additional study examined the hollow profile, for use with various other layouts of the respective fasteners, as well as to use the above principles in relation to other parts, under comparable operating conditions, and more specifically, with application in the field of Turbomachinery. For example, the comfort is and the limits of being and scope of the invention, by analogy with proposed here above to also develop and design a heat shield attached with screws to the wall of the stator and having the same hollow profile, with the internal space, aligned with the contour of the channel of the turbine, and with the outer space of the profile mounted in the stator housing by means of appropriate fasteners.

The list of items:

1 - body of the stator;

2 - cylindrical parts of the body;

3 - vane stator;

4 - inside in the radial direction Playground;

5 - outer in the radial direction Playground;

6 - lateral wall on the tail blades;

7 - lateral wall on the tail blades;

8 - pin surface;

9 - screw;

10 is a threaded nut;

11 - deepening;

12 - heat shield;

13-pin;

14 - blade impeller;

15 - element outer rim;

16 - sealing rib;

17 - sealing strips;

18 - cavity;

19 channel for passing a flow of;

20 - pin surface;

21 - pin surface;

22 - the gap;

23 - intake channel in the stator housing;

24 - inlet port in the outer area of the tail blades;

25 is a cross-bar;

26 is a cross-bar;

27 is a threaded hole;

28 - pin surface;

29 channel for the release of the cooling medium in the outer p is osadca tail blades;

30 - channel for the release of the cooling medium in the stator housing;

31 - cavity in the tail blades;

32 - bearing surface;

33 - bearing surface;

34 - vane stator;

35 - wall tail blades;

36 - pin surface;

37 - bearing surface;

38 - bearing surface;

39 is a cylindrical surface section of the casing;

40 - frontal surface area of the hull.

1. Blade (3) of the stator of an axial turbine having a channel (19)that is designed to pass the flow of gases through the turbine and executed expanding on the cone, and this blade has on its tail pad, which is connected, providing the tight fit and reliable blocking of the compounds formed with the housing (1) of the stator, characterized in that the tail blades are made in the form of a hollow profile with an inner radial direction pad (4) tail blades, which are in conformity with the contour of the channel (19)for passing a flow of gases through the turbine and located at some distance from the outer in the radial direction of the pad (5) of the tail blades, adjusted in accordance with the contour of the housing (1) of the stator, and one side wall or two essentially parallel side walls (6) and (7), with the specified outer square is a (5) is provided, at least one aperture to accommodate the appropriate fasteners (9), by means of which the blade is fixed to the body (1) of the stator.

2. Blade (3) of the stator according to claim 1, characterized in that the contact surface between the pad (5) of the tail blades and the housing (1) stator has recesses (11).

3. Blade (3) of the stator according to claim 2, characterized in that the surface (5) of the tail blades equipped executed by recesses (11).

4. Blade (3) of the stator according to claim 3, characterized in that the bearing surface (32) and (33) are the same blades (3) of the stator is made at different radial levels and connect with different surfaces of cylindrical sections (2) and bearing surface (32) of one of the vanes of the stator and the bearing surface (33) adjacent the other stator blades are located on the same cylindrical section (2) of the housing.

5. Blade (3) of the stator according to claim 1, characterized in that the outer space (5) is a removable part that is attached to the tail blades.

6. Blade (3) of the stator according to claim 5, characterized in that the outer radial ends of the side walls (6) and (7) of the tail blades bent at least approximately at right angles inward to form two contact surfaces (20) and (21)lying in parallel planes and intended DL the contact with outer space (5) of the tail blades.

7. Blade (3) of the stator according to claim 1, characterized in that provided the appropriate tools designed for supplying a cooling medium into the cavity (18) in assembled form.

8. Blade (3) of the stator according to claim 1, characterized in that is provided by the presence of two crossbars (25) and (26) between the side walls (6) and (7).

9. The blade of the stator of claim 8, wherein the end surface of the side walls (6) and (7), and cross (25) and (26)facing the surface of the cylindrical section (2) of the housing closely adjacent to the surface of the cylindrical section (2) of the housing and together with the inner space (4) they form a cavity (31), which, in essence, the seal is separated from the channel (19)for passing a flow of gases through the turbine.

10. The stator blade according to claim 1, characterized in that the side walls (6) and (7) with bearing surfaces (37) and (38) parallel to the longitudinal centerline of the stator (1), the bearing surface (37) and (38) adjacent to both the cylindrical surface (39) and the end surface (40) of the housing (1) of the stator together with the inner space (4) tail blades having a contact surface (36) and (28) and also adjacent to the said surfaces of the housing (1) of the stator, they form a cavity (31), which, in essence, the seal is separated from the channel (19)intended to skip the FL flow of gases through the turbine, and fastener (9) is inclined to the end surface (40) of the housing (1) of the stator at an angle, which can be ensured by the simultaneous pressing of the aforementioned surfaces.

11. The stator blade according to claim 1, characterized in that provided by appropriate means (23)for supplying a cooling medium into the cavity (18) or (31) mounted in them.

12. The stator blade according to claim 11, characterized in that provided by appropriate means (30), designed to release the cooling medium from the cavity (31) in assembled form.