RU2801253C1 - Axial compressor - Google Patents

Abstract

FIELD: aircraft engines.

SUBSTANCE: in the compressor housing, an additional casing is made above the two middle stages, forming a cavity with the surface of the compressor housing, which is divided by a partition into two parts with the end wall of the lower part above the axial clearance of the second stage made with a rounding, at least one slotted channel is made in the partition around the circumference near the said end wall, and a row of through slots is made in the compressor housing around the circumference, through channels are made in the compressor housing around the circumference in the area of the opposite end wall with access to the area above the impeller of the first stage or any previous stages, and the part of the casing enclosing the upper cavity is equipped with a bypass valve with a breather. The casing is made together with the compressor casing by casting from titanium or heat-resistant alloy. The use of the proposed invention will increase the overhaul life and increase the efficiency of the compressor, as well as ensure its gas-dynamic stability.

EFFECT: increased overhaul life of gas turbine engines, increased efficiency of compressors and gas-dynamic stability.

3 cl, 4 dwg

Description

The invention relates to compressors for aircraft gas turbine engines and can be used in industrial gas turbine plants, allows to increase the overhaul life of gas turbine engines (GTE), increase the efficiency of compressors and ensure their gas-dynamic stability.

Known compressor of an aircraft gas turbine engine, consisting of an inlet guide apparatus and several rims, successively alternating in the axial direction, rotor blades mounted on a rotating rotor, and guide vanes fixed in the compressor housing. The combination of one row of working blades and the next row of guide vanes forms a compressor stage. The rotor blades of one stage, installed in the disk, form an impeller (RC), and the guide vanes of one stage, fixed in the housing, form guide vanes (NA) [Inozemtsev, A.A. Gas turbine engines / A.A. Inozemtsev, V.L. Sandratsky - Inozemtsev A.A., Sandratsky V.L. Gas turbine engines - Perm: JSC "Aviadvigatel", 2006. - 1204 p. S. 220].

The disadvantage of the known design is that the compressors of gas turbine engines operated both on aircraft and in ground installations are subject to erosive wear and, to a greater extent, those that are operated in difficult climatic conditions, characterized by increased dust content and atmospheric humidity.

Erosive wear by a two-component air flow containing both solid abrasive particles and water drops is dangerous for the compressor of an aircraft gas turbine engine in that it leads to premature failure of the entire gas turbine engine due to its early removal from operation due to premature wear of the working blades, labyrinth seals and O-rings of the radial clearance of the compressor. Especially the danger of reduction of the service life of aircraft engines arises in climatic conditions with increased dust content and humidity of the atmospheric air, as a result of which the resource can be reduced by more than 10 times. Erosive wear inevitably leads to a decrease in the margin of gas-dynamic stability of the compressor ΔK _e .

It is known that erosive wear of the blades is especially intense in the middle and last stages of the compressor. This is due to the uneven distribution of the two-component air flow in the compressor flow path. Under the action of centrifugal forces from the rotation of the compressor rotor, dust and water particles acquire speed in the radial direction and have a dust boundary that moves in a tangentially axial direction along the flow path to the compressor periphery, forming a near-wall layer of a two-component dust flow near the stator housing in the zone of the middle and last stages . So, in the work [Krivosheev, I.A. Analysis of the influence of dust particles on the parameters of the stages of an axial compressor. / I.A. Krivosheev, S.A. Strugovets, R.F. Kamaeva // Bulletin of the Voronezh State Technical University. - 2011. - No. 3 (26). - T. 1. - S. 50-55], using known data, the lower boundary of the dust zone along the height of the flow path was built (by calculation). It can be seen from the results of the study that as particles move away from the compressor inlet, the lower boundary of the dusty zone moves away from the bushing. Inside this zone, the concentration of particles is uneven - it increases from the lower boundary to the periphery.

At the same time, the working and guide vanes of the first stages are subject to erosion along the entire height (to a greater extent from the side of the trough, near the leading and trailing edges), while the working blades of the last stages have a pronounced increase in erosion as they approach the end section (towards the periphery), which is due to the centrifugation of dust in the steps. In this regard, the concentration of dust at the periphery increases and the blades of the last stages, which are the thinnest, become the most wearable elements of the engine [Krivoshee, I.A. Analysis of the influence of dust particles on the parameters of the stages of an axial compressor. / I.A. Krivosheev, S.A. Strugovets, R.F. Kamaeva // Bulletin of the Voronezh State Technical University. - 2011. - No. 3 (26).-V.1. - S. 50-55.].

So, the trailing edges of the blades of the last stages of small engines, having a thickness of only 120-50 microns, can be cut by dust [Perelman, R.G. Erosion strength of parts of engines and power plants of aircraft / R.G. Perelman. - M.: Mashinostroenie, 1980. - 245 p. - S. 11-12].

To solve the problem of erosive wear of compressors, both air-cleaning devices installed on the aircraft and integrated into the engine are used. To some extent, they solve the problem of cleaning the air from dust particles and water drops, but are insufficient due to the expansion of the geography of the use of aircraft engines and individual ground power plants. Therefore, the issue of cleaning a two-component air flow with new methods and devices is relevant.

The technical result of the invention is to increase the overhaul life of the compressor by cleaning the air from solid particles of dust and water drops, as well as ensuring its efficiency and gas-dynamic stability.

This technical result is achieved by the fact that in an axial compressor, consisting of a compressor housing, impellers and guide vanes, the compressor housing above two middle stages is additionally equipped with a casing that forms a cavity with the surface of the compressor housing, which is divided by a partition into two parts, while the end wall the lower part above the axial gap of the second stage of the said two middle stages is made with a rounding, in the area of the said end wall in the partition around the circumference there is at least one slotted channel, and in the compressor housing around the circumference - one row of through slots, in the area opposite The end wall in the compressor casing has through channels along the circumference with access to the area above the impeller of the first stage of the said two middle stages, and the part of the casing covering the upper cavity is equipped with a bypass valve with a breather.

The essence of the claimed invention is illustrated by the following graphics:

fig. 1 - shows a longitudinal section of the compressor housing in the region of the middle stages as part of the GTE axial compressor;

fig. 2 shows element A in figure 1 on a scale of 7:1;

fig. 3 shows a B-B section of the device in FIG. 1;

fig. 4 shows a B-B section of the device in FIG. 1.

The essence of the invention lies in the fact that above the two middle stages the compressor is provided with a casing 4, forming a cavity, which is divided by a partition 6 into two parts, in the area of the rounded end wall 10, through slots 8 are made around the entire circumference of the compressor housing, located parallel to its axial line to ensure direct inlet of a near-wall dusty air flow with dust particles and water drops, which move by inertia along the rounded end wall 10, where, under the action of inertial and centrifugal forces, they are separated through rows of slotted channels 9 located at an angle that ensures their capture around the entire circumference of the compressor housing, and the purified air flow moves along the lower part of the cavity 7 of the casing 4 in the direction opposite to the direction of the main flow of the compressor to through channels 3 located around the entire circumference of the compressor casing with access to the area above the impeller of the first stage 1 of the two mentioned middle stages, at an angle of 1... 5° to the surface of the compressor housing [Patent No. 2582537, Russian Federation, IPC F04D 29/68 (2006.01). Axial compressor: No. 2014117379/06: App. 04/29/2014: publ. 11/10/2015 / Klepikov D.S., Alekseev I.I., Cherkasov A.N., Alekseev A.A., Sharafutdinov A.G., Zvonnikov V.I.; applicant VUNTS VVS "VVA". -11 s: ill. - Text: direct]. Air through through channels 3, entering the area above the impeller of the first stage 1 of the two middle stages mentioned, reduces secondary flows, which ensures irrotational flow in the interblade channel along the entire crown of the stage rotor and then communicates with the main compressor air flow. The separated particles passing through the rows of slot channels 9 enter the upper part of the cavity 5 of the casing 4 to trap the separated particles, where they are deposited and periodically, as they are filled, are released into the atmosphere in accordance with the control program through the bypass valve with a breather 2, and the casing is made by casting from titanium or heat-resistant alloy and is made together with the compressor.

Claims (3)

1. An axial compressor, consisting of a compressor housing, impellers and guide vanes, characterized in that the compressor housing above the two middle stages is additionally equipped with a casing that forms a cavity with the surface of the compressor housing, which is divided by a partition into two parts, while the end wall of the lower part the cavity above the axial clearance of the second stage of the said two middle stages is made with a rounding, in the area of the said end wall in the partition around the circumference there is at least one row of slotted channels, and in the compressor housing around the circumference - one row of through slots, in the area opposite The end wall in the compressor casing has through channels along the circumference with access to the area above the impeller of the first stage of the said two middle stages, and the part of the casing covering the upper cavity is equipped with a bypass valve with a breather. 2. Axial compressor according to claim 1, characterized in that through channels with access to the area above the impeller can be made above any stages up to the stage, in the area of which through slots and rows of slot channels are made. 3. An axial compressor according to claim 1 or 2, characterized in that the casing is made together with the compressor casing by casting from a titanium or heat-resistant alloy.

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