UA80669C2 - Gas turbine blade with improved cooling circuits - Google Patents

Abstract

A gas turbine blade for an airplane engine, the blade comprising at least a first cooling circuit comprising at least a concave side cavity extending radially beside the concave face of the blade, at least a second cooling circuit comprising at least one convex side cavity extending radially beside the convex face of the blade, and at least one third cooling circuit comprising at least one central cavity situated in the central portion of the blade between the concave side cavity and the convex side cavity, at least one leading edge cavity situated in the vicinity of the leading edge of the blade, communication orifices opening out into the central cavity and into the leading edge cavity, and outlet orifices opening out into the leading edge cavity and through the leading edge of the blade.

Description

Description of the invention

This invention relates to the improvement of gas turbine blades for an aircraft engine. More specifically, the 2nd invention relates to the cooling circuit of such blades.

It is known that rotating aircraft engine gas turbine blades, especially high pressure turbine blades, are exposed to very high combustion gas temperatures during turbine operation. These temperatures reach values that significantly exceed the temperatures that can withstand without damage various parts that come into contact with these gases. This fact limits the service life of such parts. 70 On the other hand, it is known that increasing the temperature of the gases in the high-pressure turbine increases the efficiency of the engine and, therefore, the ratio of engine thrust to the weight of the aircraft, which is driven by this engine. In this regard, attempts are being made to create turbine blades capable of withstanding increasingly high temperatures.

A known approach to solving this problem is by equipping the blades with cooling circuits designed to reduce the temperature of the blades. When using such contours, cooling air, as a rule, is supplied to the inside of the feather blade through its root part (tail), passes through the blades along the path determined by the cavities formed inside the feather, and exits through the outlet (perforation) holes in the surface of the feather.

As an example, a known method can be indicated, which consists in making a blade with a central cavity, into which cooling air is supplied through the root part in order to perform a "shock action" (that is, to create a high-speed thrust) on the leading edge of the blade. However, since the specified cavity is separated from the hot gases only by the wall of the blade, the air passing through the specified cavity heats up as it approaches the outlet edge.

US Patent No. 5720431) describes a blade equipped with a central cavity around which there are radial cavities located on the convex and concave sides of the blade. The mentioned document also describes openings that allow air to pass between the central cavity and the radial cavities. As a result (9), the air that passes through the radial cavities heats up to a small extent and almost does not lose its effectiveness in protecting the inlet edge of the blade from hot gases.

This invention is aimed at solving the problem of reducing the shortcomings of known solutions by improving the blades of gas turbines, more precisely, their cooling circuits in such a way as to reduce the temperature of the front edge of the blade blade. This increases the service life of the blades. Gee)

As part of solving the mentioned problem, the invention provides for the creation of a gas turbine blade for an aircraft engine. The vane according to the invention is characterized by the fact that it is equipped with: o - at least the first cooling circuit, which contains at least one cavity on the concave side of the vane, extending in the radial direction near the concave surface of the vane;

Zo - at least the second cooling circuit, which does not depend on the first cooling circuit and contains at least one cavity on the convex side of the pen, elongated in the radial direction near the convex surface of the pen; - at least one third cooling circuit, which does not depend on the first and second cooling circuits and "contains at least one central cavity located in the central part of the blade blade between the cavity on the concave side of the blade and the cavity on the convex side of the blade, at least one cavity near c of the input edge of the pen, connecting holes connecting the central cavity and the cavity near the input edge of the pen, as well as outlet holes communicating with the specified cavity near the input edge of the pen and exiting to the input edge of the pen.

The presence of cavities around the central cavity, as well as the use of independent cooling circuits 49 for different cavities, allows for essentially uniform protection of the blade feather along its entire height. As a result, the leading edge of the pen receives effective cooling with colder air. av | In addition, the cooling of the convex and concave surfaces in the central part of the blade feather is provided by two completely independent cooling circuits. Thanks to this, it becomes possible to independently control the temperatures of the concave and convex surfaces of the pen by controlling the flow of cooling air that is supplied to each of these circuits.

In addition, there is no radial air circulation in the cavity located near the leading edge of the pen. c Cool air is released directly into the flow of combustion gases through the exhaust holes located at the inlet edge. This allows you to avoid the disturbing effect of the cross flow on the action of air jets, which are supplied with a high-speed pressure. 29 List of drawing figures

GF) Other features and advantages of this invention will be clear from the following detailed description with reference to the accompanying drawings, which show one of the possible embodiments of the invention. o In Fig. 1, a rotating blade of a gas turbine made in accordance with the invention is shown in cross-section.

In Fig. 2, the same blade is presented in a section along the line I-II in Fig. 1. 60 In Fig. 3, the same blade is presented in cross-section along the line PI-III in Fig. 1.

Figure 4 shows an enlarged view of the holes that connect the central cavity and the cavity near the leading edge of the blade feather according to the invention.

Fig. 5 is a cooling air circulation diagram.

Information that confirms the possibility of implementing the invention As shown in Fig. 1, the blade of a gas turbine for an aircraft engine, made in accordance with the invention, contains in the central part of its feather the first and second cooling circuits A and B, made independent of each other. The first contour A contains at least one cavity on the concave side of the pen, but preferably a group of cavities, for example, three cavities 2a, 25 and 2c on the concave side of the pen. These cavities are elongated in the radial direction near the concave surface Ta (notchov) of the feather blade 1. The second cooling circuit B contains at least one cavity on the convex side of the feather, but preferably a group of cavities, for example, four cavities 4a - 44 on the convex side of the feather. These cavities are elongated in the radial direction near the convex surface 15 (back) of the blade feather 1.

The specified contours are intended for cooling, respectively, the concave and convex surfaces of the pen in a mode that will be described in detail below. 70 As more clearly shown in Fig. 2, the air inlet 14, which provides air access to the first cooling circuit A, is provided at that radial end of the first cavity 2a on the concave side of the pen, which is adjacent to the root part of the blade.

The first channel 16 connects the second radial end of the cavity 2a, adjacent to the outer edge of the blade, with the adjacent radial end of the second cavity 25 on the concave side of the pen. Near the root part of the blade /5, a second channel 18 is also provided, which connects the second radial end of the cavity 25 with the adjacent radial end of the third cavity 2c on the concave side of the pen. At the same time, the outlet (perforation) holes (20) connect the indicated cavity 2c with the concave surface of the pen.

Cavities 2a, 25 and 2c on the concave side of the pen, which are included in the first cooling circuit A, are best equipped with deflectors 46 located on their outer wall adjacent to the concave surface of the pen, which increase heat transfer along the specified wall and reduce pressure losses.

Deflectors are made in the form of relief areas on the walls of the cavities located on the path of the cooling air flow. Therefore, they serve to introduce disturbances into the air flow that flows through the cavities, and thereby enhance heat exchange.

The power supply of the second cooling circuit B is carried out independently of the first circuit A. As shown in Fig. As shown, the second circuit B includes four cavities 4a, 46, 4c and 44 on the convex side of the vane blade and at least two inlets 22a and 226 on those radial ends of the cavities 4a and 4B which are adjacent to the root i) part of the vane.

At the same time, the first and second channels 24, 26 connect the opposite radial ends of the cavities 4a and 45 on the convex side of the pen, respectively, with the adjacent radial end of the third cavity 4c. The third channel 28 connects Ge! from the second radial end of the cavity 4c with the adjacent radial end of the fourth cavity 44 on the convex side of the pen. X,

Perforation holes 30 are also made in the convex surface 15 of the blade, near its leading edge, which are connected to the specified cavity 44 on the convex side of the pen.

Cavities 4a and 44 on the convex side of the pen are preferably equipped with deflectors 44 located on their outer walls, adjacent to the convex surface of the vane, which increase heat transfer along these walls.

In the best version, cavities 2a - 2c on the concave side of the pen, which are included in the first cooling circuit

A, and cavities 4a - 44 on the convex side of the pen, which are included in the second cooling circuit B, have a high characteristic ratio to increase internal heat transfer. A cooling cavity is considered « 470 to have a high characteristic ratio if, in its cross-section, its largest dimension s (length) is at least three times its other dimension (width).

And so, according to the invention, the concave and convex surfaces of the pen are cooled completely independently, with и? using two separate circuits A and B, that is, there is no air flow from one circuit to another.

Thanks to this, it is possible to independently control the temperature of the concave and convex surfaces of the vane pen using the flow of air flowing in each of these contours.

Go! In addition to the first and second cooling circuits A and B, blade 1 also has a third cooling circuit C, independent of the other two and located between them. This third cooling circuit C contains at least one o central cavity 6 located in the central part of the blade between cavities 2a - 2c on the concave side

He" pen and cavities 4a - 44 on the convex side of the pen. The cavity 8, which has smooth walls and is located near the leading edge of the blade, is connected to the central cavity 6 by means of connecting holes 10.

Me. Outlet (perforation) holes 12 are also provided, which connect the cavity 8 near the inlet edge of the blade with

Ge by the specified inlet edge of the cooling circuit, i.e. in such a way as to optimize heat exchange as a result of high-speed air pressure on the inlet edge 1s. The connecting holes are made in such a way as to avoid sharp edges and thereby eliminate the risk of cracks during the formation of the cooling circuit during the casting process.

At the same time, the cooling air that enters the central cavity is supplied only through the connecting holes in this cavity to the front edge of the blade. Thanks to this, the flow of air that passes through this circuit does not depend on the static pressure on the blades. The distribution of the flow that passes through the connection holes is uniform along its height.

At the same time, the central cavity 6 is protected from hot gases due to the fact that it is located between two other cooling circuits A | A. As a result, the air passing through this cavity is heated only slightly. As a result, the leading edge of the blade is effectively cooled by air at a lower temperature.

The blade in the described embodiment is additionally equipped in its rear part with a fourth cooling circuit 0. This circuit is independent of the first, second and third circuits A, B and C. It is formed by at least one cavity, but in the best version - a group of cavities 32, 32" , 32", located in the rear part of the feather blade 1 (see Fig. 1). A corresponding air inlet (not shown) is located at the radial end of the cavity 32, which is adjacent to the root part of the blade, and the outlet holes 36 connect the cavity 32" to the concave surface 1a of the pen.

In the best version, the cavities 32, 32", 32" of the fourth cooling circuit of the OU are equipped with deflectors 48, located opposite each other on the concave and convex side walls of the named cavities to enhance heat transfer along the specified walls.

Finally, a fifth cooling circuit E is also provided, which is independent of the other four circuits A -

Yur. This circuit serves to cool the output edge 14 of blade 1.

The fifth cooling circuit E contains at least one cavity 38 near the output edge 14 of the blade and an inlet 70 (not shown) for supplying cooling air to this circuit E, located at the radial end of the cavity 38, which is adjacent to the root part of the blade. There are also outlet openings 42 that connect the indicated cavity 38 and the outlet edge 14 of the blade.

Cavity 38 near the exit edge is preferably equipped with deflectors located opposite each other on the concave and convex side walls of the vane to enhance heat transfer along /5 said walls.

The method of cooling the blade is obvious from the given description of its design, so it will be described very briefly, mainly with reference to Fig.5.

Fig. 5 is a diagram of the circulation of cooling air, which flows through various cooling circuits A - E, made in the blade according to this invention. As already mentioned, all these circuits are made independent of each other, since each of them has its own inlet for cooling air.

Cooling air enters the first cooling circuit A through cavity 2a on the concave side of the pen.

After that, the cooling air passes along the cavity 25 on the concave side of the pen, and then along the third cavity 2c on the same side of the pen, before it exits through the outlet openings 20, which are on this side. with

At the same time, cooling air is supplied to the second cooling circuit B through two chambers 4a, 45 on the convex side of the pen. Deviation of both air flows near the outer edge of the pen directs these flows along i) cavity 4c. After that, the air enters the cavity 44, before it leaves this cavity through the outlet holes З0 through the convex surface 1b of the blade.

In the third cooling circuit C, air is supplied to the central cavity 6 directly from the root He! from part of the blade and is used to feed the cavity 8 near the inlet edge of the blade through the connecting holes 10. The possibility of cooling the inlet edge 1c is also provided by the presence of holes 12, which are removed from this edge. "at

The rear part of the blade 1 is cooled by the fourth circuit 0, which contains three cavities 32, 32, 32". As shown in Fig. 5, the cooling air is supplied to one of the cavities (cavity 32), after which it is deflected near the outer edge of the feather, passes through the cavity 32", after which it enters the cavity co 32", before it leaves this cavity through the outlet holes 36.

And, finally, the output (rear) edge 14 of the blade is cooled with the help of the fifth cooling circuit E, and the cooling air is fed directly into the cavity 38 of this circuit.

It is clear from the above description that this invention has a number of advantages. It is especially important that small "cavities around the central cavity make it possible to isolate it from hot gases. Under such conditions, the air that passes along the central cavity is heated to a lesser extent than in known devices, so the outer parts of the blade are cooled by colder air, that is, with greater efficiency. ;" Since the temperature of the inlet edge of the vane feather becomes lower, the service life of the vane increases and increased resistance to oxidation of the metal wall of the vane, as well as peeling of the coating, which forms a thermal barrier, is achieved in the zone that is particularly exposed to external influences.

Go! In the circuits that serve to cool the central part of the blade, deflectors are provided only on the outer sides of the cavities. The deflectors serve, first of all, to increase heat exchange through the walls and, therefore, to reduce temperatures on the outer walls of the blade. In addition, they contribute to obtaining optimal pressure loss values.

The listed advantages allow you to get a profit from the uniform cooling of the leading edge of the pen along its length

Me, its height in the form of cooling air consumption and temperature level. As lower values are reached

At higher temperatures, it becomes possible to increase the service life of the blade.

It is obvious that the present invention is not limited only to the described variant of implementation, but covers any possible modifications. For example, the described cooling circuits can be provided both in fixed and rotating blades. 000 madyans fight ska and not I

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Claims (10)

The formula of the invention of 1. A gas turbine blade (1) for an aircraft engine, characterized in that it is equipped with at least a first cooling circuit (A) that contains at least one cavity (2) on the concave side of the blade b" of the blade, extending in the radial direction near the concave surface (ta) a pen, at least with a second cooling circuit (B), which is independent of the first cooling circuit (A) and contains at least one cavity (4) on the convex side of the pen, elongated in the radial direction near the convex surface of the pen, third and) cooling circuit (C), which is independent of the first and second cooling circuits and contains at least one central cavity (6) located in the central part of the vane feather between the cavity (2) on the concave side of the feather and the cavity (4) on the convex side of the feather , at least one cavity (8) near the inlet edge (1c) of the pen, connecting holes (10) connecting the central cavity and the cavity near the inlet edge of the pen, as well as outlet holes (12), etc. о connect with the indicated cavity near the inlet edge of the pen and go to the inlet edge (1c) of the pen. " 2. The blade according to claim 1, characterized in that the first cooling circuit (A) contains at least three cavities (2a, 26 and 2c) on the concave side of the pen, at least one air inlet (14) at the radial end of the first cavity (2a) on the concave side of the pen for supplying cooling air to the first "" cooling circuit (A), the first channel (16) connecting the second radial end of the first cavity (2a) with " the adjacent radial end of the second cavity (25) on on the concave side of the pen, the second channel (18) connecting the second radial end of the second cavity (25) with the adjacent radial end of the third cavity (2c) on the concave side of the pen, the outlet holes (20) that communicate with the indicated third cavity and exit on the concave surface (Ta) of the pen. at 3. The blade according to claim 1 or 2, which is characterized in that the second cooling circuit (B) contains at least four cavities (4a - 44) on the convex side of the pen, at least two air inlets (14) on the radial (22) end of the first and the second cavities (4a, 45) on the convex side of the pen for supplying cooling air to the second FO 20 cooling circuit (B), the first and second channels (24, 26), which connect the second radial ends of the specified first and second cavities with the adjacent the radial end of the third cavity (4c) on the concave side of the pen, Me, the third channel (28) connecting the second radial end of the third cavity with the adjacent radial end of the fourth cavity (44) on the convex side of the pen, outlet holes (30), which connect with the specified fourth cavity and exit to the convex surface (15) of the feather. 52 4. The paddle according to any of claims 1 - 3, which is characterized by the fact that it is additionally equipped with at least one Ge! a fourth cooling circuit (0) independent of the first, second and third cooling circuits and such that it contains at least one cavity (32) located in the rear part of the vane feather (1), an air inlet at the radial end of said cavity for supply of cooling air to the fourth cooling circuit (0) and inlet holes (36), which communicate with the indicated cavity and exit to the 60 concave surface (Ta) of the pen. 5. The blade according to claim 4, which is characterized in that the cavity (32) of the fourth cooling circuit (0) is equipped with deflectors (48) located opposite each other on its concave and convex side walls to enhance heat transfer along said walls. 6. The blade according to any of the preceding points, which is characterized in that it is additionally equipped with at least b5 one fifth cooling circuit (E), independent of the first, second, third and fourth cooling circuits and such that it contains at least one cavity (38) located near the outlet edge of the vane feather (1), an air inlet at the radial end of the specified cavity near the outlet edge of the feather for supplying cooling air to the fifth cooling circuit (0) and outlet openings (42) that communicate with specified cavity and exit to the output edge (14) of the pen. 7. The blade according to point b, which is characterized by the fact that the cavity (38) near the exit edge of the pen is equipped with deflectors (50) located opposite each other on its concave and convex side walls to enhance heat transfer along the indicated walls. 8. A blade according to any of the previous items, which is characterized in that the cavity (2) is on the concave side of the pen of the first cooling circuit (A) and the cavity (4) is on the convex side of the pen of the second cooling circuit 7/0. "B) have a high characteristic ratio for increasing internal heat transfer. 9. The blade according to any of the preceding points, which is characterized in that the cavity (4) on the convex side of the pen of the second cooling circuit (B) is equipped with deflectors (44) located on its outer convex side wall to enhance heat transfer along its walls. 10. The blade according to any of the preceding points, which is characterized by the fact that the cavity (2) on the concave side /5 of the pen of the first cooling circuit (A) is equipped with deflectors (46) located on its outer wall near the concave surface of the pen to enhance heat transfer along the specified wall while simultaneously reducing pressure losses. Official Bulletin "Industrial Property". Book 1 "Inventions, useful models, topographies of integrated circuits", 2007, M 17, 25.10.2007. State Department of Intellectual Property of the Ministry of Education and Science of Ukraine. c schi 6) (o) (Se) (Se) «c) d) - with . and? (ee) («c) (o) (o) 3e) ime) 60 b5