CN215860346U - Integrated structure device of active clearance control system of low-pressure turbine of aircraft engine - Google Patents

Abstract

One aspect of the present disclosure relates to an integrated structural assembly for an aircraft engine low pressure turbine active clearance control system, comprising an inner casing of the low pressure turbine; an outer casing of the low pressure turbine, the outer casing including a plurality of openings at a front end and an exhaust hole at a rear end; a cavity between the inner case and the outer case; the flow distribution ring is annular and is arranged at the front end of the outer casing, and comprises a plurality of drainage holes for guiding cooling gas to a plurality of openings of the outer casing; wherein the cooling gas introduced from the plurality of openings of the front end of the outer case cools the inner case axially from front to rear within the cavity and is discharged from the exhaust hole to the outside, and wherein the inner surface of the outer case includes a wrinkled surface to cause gas backflow, thereby increasing a contact time of the cooling gas with the outer surface of the inner case.

Description

Integrated structure device of active clearance control system of low-pressure turbine of aircraft engine

Technical Field

The present application relates generally to aircraft engine air systems and structures thereof, and more particularly to low pressure turbine active clearance control systems and structures thereof.

Background

The low-pressure turbine unit body casing structure can generate excessive expansion when the temperature is too high, so that the clearance between a low-pressure turbine (LPT) blade tip and the casing is too large, airflow flows out from the clearance, and the work efficiency of the turbine is reduced.

A low pressure turbine clearance active control (LPTACC) system is a system that controls Low Pressure Turbine (LPT) tip clearance by cooling the low pressure turbine unit body case structure, thereby reducing fuel consumption and improving engine performance. For example, the opening of the LPTACC shutter may be controlled by the engine electronic controller EEC, adjusting the amount of cooling gas bleed air to increase or decrease the amount of fan outlet air flowing to the LPT case. Thus, the low pressure turbine unit body casing structure is cooled by the cooling gas to maintain the LPT tip clearance to the minimum thermal expansion, thereby improving the fuel efficiency.

Disclosure of Invention

One aspect of the present disclosure relates to an integrated structural assembly of an aircraft engine low pressure turbine active clearance control system, comprising an inner casing of a low pressure turbine; an outer casing of the low pressure turbine, the outer casing comprising a plurality of openings at a front end and a plurality of exhaust holes at a rear end; a cavity between the inner case and the outer case; the flow distribution ring is annular and is arranged at the front end of the outer casing, and comprises a plurality of drainage holes for guiding the cooling gas to a plurality of openings of the outer casing correspondingly; wherein the cooling gas introduced from the plurality of openings of the front end of the outer case cools the inner case axially from front to rear within the cavity and is discharged from the plurality of exhaust holes to the outside, and wherein the inner surface of the outer case includes a wrinkled surface to cause gas backflow, thereby increasing a contact time of the cooling gas with the outer surface of the inner case.

According to an exemplary embodiment, the integrated structural device further comprises a shutter connected to the fan outlet or the bypass bleed air for adjusting the ratio of hot air to cold air to obtain different temperatures of the cooling air.

According to an exemplary embodiment, wherein the splitter ring further comprises an air line for connecting the shutter, and the splitter ring is fixed to the front end of the outer casing by a bracket.

According to an exemplary embodiment, the plurality of drainage apertures open in a rearward direction.

According to an exemplary embodiment, the plurality of drainage holes comprises circular holes of 3mm in diameter punched every 5mm on the drainage ring by a laser drilling technique.

According to an exemplary embodiment, the outer casing comprises a high-strength, lightweight material.

According to an exemplary embodiment, the outer casing is substantially conformal with the inner casing.

According to an exemplary embodiment, the outer surface of the inner case comprises a smooth surface.

According to an exemplary embodiment, the corrugated surface includes a zigzag-shaped corrugated surface including a side normal to the inner surface of the outer casing and a side obliquely forward.

According to an exemplary embodiment, an angle between a side of the saw-tooth shape inclined forward and a side normal to an inner surface of the outer pocket is 45 degrees, and a height of the saw-tooth shape accounts for 70% of a total height of the cavity.

The present disclosure also includes other related aspects.

Drawings

Fig. 1 illustrates a schematic diagram of an LPTACC system in accordance with an aspect of the present disclosure.

Fig. 2 illustrates a cross-sectional view of an integrated structural assembly of an LPTACC system according to an aspect of the present disclosure.

Fig. 3 shows a cross-sectional view of an integrated structural assembly of an LPTACC system according to another aspect of the present disclosure.

Fig. 4 illustrates a schematic diagram of a diverter ring design for an LPTACC system in accordance with an aspect of the present disclosure.

Fig. 5 illustrates an installed perspective view of an integrated structure of an LPTACC system according to an aspect of the present disclosure.

Fig. 6 shows a schematic diagram of a design of LPT inner and outer casing cavities according to an alternative embodiment of the present disclosure.

Detailed Description

The active main stream civil aviation engine almost all uses the LPTACC system in order to improve engine performance, and the cooling mode generally adopts fan export/outer duct bleed air, adjusts bleed air quantity through the LPTACC valve, and then supplies to the LPTACC house steward, and the LPTACC house steward distributes respectively and supplies to a plurality of branch pipes with cooling aperture.

Fig. 1 illustrates a schematic diagram of an LPTACC system 100 in accordance with an aspect of the present disclosure. As shown in fig. 1, LPTACC shutter 102 has an inlet 104 connected to a fan outlet or bypass bleed air, and an outlet 106 connected to one end of an LPACC air line 108.

The other end of the LPACC air line 108 is connected to an LPACC manifold 110 and leads from the manifold 110 into a plurality of branch lines 112. The branch pipe 112 is provided with a plurality of cooling holes (not shown) spaced at intervals for spraying cooling gas toward the casing. The manifolds 112 are wound at regular intervals around the LPT casing and cool the low pressure turbine unit body casing structure 114 by the cooling gas ejected from the cooling apertures.

However, because of the inherent distance between the manifolds 112 and the inability to eliminate this natural deficiency, only the portion of the LPT case around the exit area of the cooling apertures can be cooled, and substantially uniform cooling of the entire low pressure turbine case is not achieved. This eventually leads to a situation where both local high temperature and local low temperature of the LPT casing exist, so that the LPTACC cooling effect is not ideal. In addition, thermal stress effects may occur due to the presence of localized high and low temperatures. And the performance requirements for the structural material are very high. If the material performance of the LPT casing does not reach the standard or the engine ages, the LPT casing is likely to crack, so that more serious consequences are caused, even the engine is idle stopped, and the operation efficiency of the airplane is affected.

Fig. 2 illustrates a cross-sectional view of an integrated structural assembly 200 of an LPTACC system according to an aspect of the present disclosure. As seen in fig. 2, unlike the solution of fig. 1, the integrated structural assembly 200 of the LPTACC system of fig. 2 includes a double-layered hollow casing structure, i.e., an LPT outer casing 202 and an LPT inner casing 204, and a cavity 210 sandwiched therebetween.

According to some exemplary embodiments, the LPT outer casing 202 and the LPT inner casing 204 may be substantially conformal. According to some embodiments, the inner surface of the LPT outer casing 202 and the outer surface of the LPT inner casing 204 may be smooth. In accordance with at least some example embodiments, the height of the cavity 210 between the LPT outer casing 202 and the LPT inner casing 204 may be substantially uniform.

According to an exemplary embodiment, the outer casing 202 of the double-layered hollow casing includes an opening 205 at a front end thereof, a plurality of exhaust holes 206 at a rear end thereof, and a fixing structure 208. The securing structure 208 is used to connect the double-walled hollow casing structure by, for example, a bolt fastener or the like.

According to an exemplary embodiment, the structural material of the LPT inner case 204 may be consistent with prior art cases (e.g., using a high temperature alloy, a titanium alloy, etc.), while the material of the LPT outer case 202 may preferably be a high strength, lightweight material, such as a lightweight alloy material such as an aluminum alloy, which may achieve as little additional weight gain as possible.

As shown in fig. 2, cooling gas may enter a cavity 210 between the inner and outer casings 202 and 204 of the double-walled hollow casing structure, for example, from an LPTACC shutter through an opening 205. Because the cooling gas flow field in the cavity 210 is uniformly distributed and has a constant direction, the inner casing 204 in the LPT can be effectively, uniformly and fully cooled. The resulting cooling gas exits through a plurality of exhaust ports 206 at the rear end of the outer casing 202, thereby achieving sufficient, efficient, and uniform cooling of the LPT casing structure. By accurately adjusting the bleed air amount of the LPTACC shutter (not shown), the problem of local thermal stress caused by uneven cooling can be avoided, thereby improving the durability and the operating efficiency of the engine.

Due to the integrated structure design of the casing and the pipeline in the scheme of the figure 2, the pipelines such as a main pipe and a branch pipe, and the structures such as a bracket and a fastener for the pipelines are eliminated, so that the weight of the engine and the later maintenance cost are effectively reduced. The scheme can solve the problems of uneven and insufficient cooling of an LPT casing structure, thermal stress of the casing and the like in an LPTACC system of the aircraft engine.

Fig. 3 shows a cross-sectional view of an integrated structural assembly 300 of an LPTACC system according to another aspect of the present disclosure. The arrangement of fig. 3 is similar to the arrangement of fig. 2. The integrated structural assembly 300 of the LPTACC system of fig. 3 includes a double-layered hollow casing structure, i.e., an LPT outer casing 302 and an LPT inner casing 304, and a cavity 310 sandwiched therebetween. The front end of the outer casing 302 of the double-walled hollow casing includes an opening 305, and the rear end includes a plurality of exhaust holes 306 and a fixing structure 308. The securing structure 308 is used to connect the double-walled hollow casing structure by, for example, a bolt fastener or the like.

Likewise, the structural material of the LPT inner case 304 may be consistent with prior art cases (e.g., using a high temperature alloy, a titanium alloy, etc.), while the material of the LPT outer case 302 may preferably be a high strength, lightweight material (e.g., an aluminum alloy, etc.), which may result in as little additional weight gain as possible.

Unlike the unitary structural assembly 200 of the LPTACC system of fig. 2, fig. 3 further incorporates a diverter ring 312. The inlet of the splitter ring 312 is connected to the LPTACC damper (not shown) and directs the cooling gas from the LPTACC damper after steady flow through the flow guide holes 305 to the opening of the LPT outer casing. Through the openings of the LPT outer case, cooling gas can enter the cavity of the double-layer hollow case structure.

Fig. 4 illustrates a schematic diagram of a diverter ring design 400 of an LPTACC system in accordance with an aspect of the present disclosure. As shown in fig. 4, LPTACC flapper 402 is connected to diverter ring 406 by LPTACC line 404. The diverter ring is annular and may be disposed at the LPT outer casing front end of a double-deck hollow casing structure of an integrated structural assembly (e.g., 300 in fig. 3 above) of an LPTACC system.

According to an exemplary embodiment, the diverter ring 406 may include a plurality of flow guide holes 408 for stably guiding the cooling gas from the LPTACC damper to the opening at the front end of the outer casing of the double-deck hollow casing for entry into the cavity between the inner and outer casings. The opening direction of the drainage holes can be backward. After stable drainage through the splitter ring, can make the gaseous flow field distribution of cooling more even, the direction is more invariable in the cavity between inside and outside quick-witted casket to can carry out more effective, more even, more abundant cooling to the quick-witted casket in LPT, avoid because of the inhomogeneous local thermal stress problem that leads to of cooling, thereby improve engine durability and operating efficiency better.

For example, according to an exemplary embodiment, the flow diverter holes 408 may be disposed at locations where the diverter ring 406 connects to the LPT case structure. For example, circular holes with a diameter of, for example, 3mm may be drilled in the splitter ring every 5mm, for example, by laser drilling, for uniformly introducing the cooling gas in the splitter ring into the inner and outer casing cavities through the openings of the LPT outer casing. As such, the disclosed solution converts the flow direction of the cooling air flow from the conventional local radial vertical cooling mode to the axial front-to-back globally uniform cooling mode. As can be appreciated, the above are merely examples. The perforation technique, spacing, location, size and shape of the drainage apertures of the present application are not limited thereto.

The scheme of the disclosure enables the LPTACC system to eliminate the need for structural arrangements of an LPTACC main pipe, a plurality of branch pipes, brackets, fasteners and the like in the traditional scheme, thereby reducing the weight of an engine and the maintenance cost. The scheme of the disclosure further does not need to arrange the cooling small holes on the branch pipes, so that the problems of uneven further cooling and the like caused by blockage of partial cooling small holes and the like can be avoided.

The LPTACC valve can realize different cooling gas temperatures by adjusting different proportions of hot gas and cold gas. The cooling gas temperature is controlled by controlling the proportion, so that the clearance between the LPT blade tip and the casing can be accurately adjusted, the generation of local thermal stress is avoided, the fuel combustion efficiency of the engine can be effectively improved, the potential safety hazard of idle stop of the engine is eliminated, the operating efficiency of an airline company is finally improved, the corresponding stop maintenance cost is reduced, and the reliability and the economical efficiency of the engine are improved.

Fig. 5 illustrates an installed perspective view of an integrated structure 500 of an LPTACC system according to an aspect of the present disclosure. As shown in fig. 5, the Low Pressure Turbine (LPT) is generally located aft of the air system of the aircraft engine. In the example of fig. 5, the unitary structure 500 of the LPTACC system may include a double-walled hollow case. The double-walled hollow case may include the LPT outer case 502 and an LPT inner case therebelow (not shown), as well as a gap between the inner and outer cases (not shown). The LPTACC flapper (on the other side) delivers the cooling gas to the diverter ring 504 through LPTACC tubing. The diverter ring 504 is secured to the exterior of the LPT by a bracket 508, such as may be generally secured to the front end of the LPT outer casing 502.

According to an exemplary embodiment, there may be 4 brackets 508 in total, 2 on each of the left and right sides of the engine, but the disclosure is not limited thereto. At the aft end of the LPT outer case, a plurality of exhaust ports 506 may be provided for exhausting cooling air from the inner and outer case cavities. For example, according to an exemplary embodiment, one circular vent 506, having a diameter of, for example, 5cm, may be provided every, for example, 10 cm. As can be appreciated, the above are merely examples. The perforation technique, spacing, location, size and shape of the vent holes of the present application are not limited thereto.

The splitter ring 504 directs the steady flow of cooling gas from the LPTACC valve to an opening (not shown) in the front end of the LPT outer casing 502 of the double-walled hollow casing. The cooling gas forms a cooling gas flow field which is uniformly distributed and has a constant direction in a cavity between the inner casing and the outer casing of the double-layer hollow casing so as to effectively, uniformly and fully cool the inner casing of the LPT. The resulting cooling gas exits through a plurality of exhaust ports 506 at the rear end of the LPT outer casing 502, thereby achieving sufficient, efficient, and uniform cooling of the LPT casing structure, particularly the LPT inner casing. By accurately adjusting the bleed air amount of the LPTACC shutter (not shown), the problem of local thermal stress caused by uneven cooling can be avoided, thereby improving the durability and the operating efficiency of the engine.

Fig. 6 shows a schematic diagram of a design 600 of LPT inner and outer casing cavities according to an alternative embodiment of the present disclosure. As can be seen in fig. 6, alternative embodiments of the present disclosure may include other implementations in addition to the aforementioned designs (i.e., both the outer and inner casing walls are smooth). In fig. 6 (a), the inner wall of the outer case 602a may include a corrugated surface in a saw-tooth shape, while the outer wall of the inner case 604a may remain smooth, thereby forming the cavity 610 a. The serrations may include a side generally normal to the inner surface of the outer casing and a side obliquely forward. According to some exemplary embodiments, the angle of the side of the pleat that is inclined forward may be, for example, 30 to 60 degrees. According to a preferred embodiment, the fold angle between the two sides may be inclined by 45 degrees.

In fig. 6 (b), the inner wall of the outer case 602b may include an arcuately protruding corrugated surface, while the outer wall of the inner case 604b may remain smooth, thereby forming the cavity 610 b. The airflow may pass through the cavities 610a and 610b in the direction of the arrows.

According to some exemplary embodiments, the height of the corrugations of the inner wall of the outer casing may account for, for example, 30-80% of the total height of the cavity. According to a preferred embodiment, the height of the corrugations (e.g. saw tooth shape) may for example account for 70% of the total height of the cavity. For example, in one example, the total cavity height may be, for example, 10mm, while the pleat height may be, for example, 7 mm.

The purpose of the inner casing wall comprising corrugations is to cause a backflow of gas, causing local turbulence, thereby increasing the contact time of the cooling gas with the outer surface of the inner casing, thereby enabling the cooling capacity of the casing to be controlled more accurately. The inner barrel outer wall can be kept smooth to facilitate uniform cooling.

Fig. 6 (a) and (b) are only exemplary embodiments. Those skilled in the art will appreciate that other designs may be employed in which the inner wall of the outer casing includes corrugations to increase gas backflow to increase contact time of the cooling gas with the inner casing surface.

The present disclosure relates to a device for integrated structure of casing and pipeline in LPTACC system, which changes the traditional radial air supply cooling mode into the mode of air supply cooling along the axial direction of engine, etc., thus cooling all areas of LPT casing. The LPT casing structure design of the present disclosure may include a double-layer casing structure, wherein the cooling gas from the LPTACC valve is stably guided by the splitter ring and then introduced into the casing cavity. Because the cooling gas flow field in the cavity is uniformly distributed and has a constant direction, the inner casing of the LPT can be effectively, uniformly and fully cooled, and finally the cooling gas flows out of the outer casing. In addition, due to the structure integrated design of the scheme, the installation of structures such as pipelines, supports and fasteners is eliminated, and the weight of the engine and the maintenance cost in the later period are effectively reduced.

It is to be understood that the claims are not limited to the precise configuration and components illustrated above. Various changes, substitutions and alterations in the arrangement, operation and details of the method and apparatus described above may be made without departing from the scope of the claims.

Claims (10)

1. An integrated structural assembly of an aircraft engine low pressure turbine active clearance control system, comprising:

an inner casing of the low pressure turbine;

an outer casing of the low pressure turbine, the outer casing comprising a plurality of openings at a front end and a plurality of exhaust apertures at a rear end;

a cavity between the inner case and the outer case;

a diverter ring, said diverter ring being annular and disposed at a forward end of said outer case, said diverter ring including a plurality of bleed holes for directing said cooling gas to said plurality of openings of said outer case, respectively; wherein

Cooling gas introduced from the plurality of openings at the front end of the outer casing cools the inner casing axially forward and aft within the cavity and is exhausted outboard from the plurality of exhaust holes, and wherein

The inner surface of the outer casing includes a corrugated surface to cause backflow of gas, thereby increasing contact time of the cooling gas with the outer surface of the inner casing.

2. The integrated structural assembly of claim 1, further comprising:

and the valve is connected to the fan outlet or the outer duct bleed air and is used for adjusting the ratio of hot air to cold air to obtain different temperatures of the cooling air.

3. The integrated structural device of claim 2, wherein said diverter ring further comprises an air line for connecting said valve, and

the shunt ring is fixed at the front end of the outer casing through a support.

4. The integrated structural device of claim 3, wherein the plurality of drainage apertures open in a rearward direction.

5. The integrated structural device of claim 4, wherein the plurality of drainage holes comprise circular holes of 3mm diameter punched every 5mm on the drainage ring by a laser drilling technique.

6. The integrated structural assembly of claim 1, wherein the outer casing comprises a high strength, lightweight material.

7. The integrated structural device of claim 1, wherein the outer case is substantially conformal with the inner case.

8. The integrated structural assembly of claim 1, wherein the outer surface of the inner case comprises a smooth surface.

9. The integrated structural device of claim 1, wherein the corrugated surface comprises a saw-tooth shaped corrugated surface comprising a side normal to the inner surface of the outer casing and a side obliquely forward.

10. The integrated structural device of claim 9, wherein an angle between a side of the saw-tooth shape inclined forward and a side normal to an inner surface of the outer casing is 45 degrees, and a height of the saw-tooth shape accounts for 70% of a total height of the cavity.

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