RU2189499C2 - Gas-turbine engine compressor - Google Patents

Abstract

FIELD: gas-turbine engine compressors. SUBSTANCE: compressor has stator with bypass body and inner body which form circular closed cavities connected with flow section of compressor at inlet and with bypass valves at outlet. Bypass valves are mounted in one radial plane alternating in circumferential direction; second (in way of air flow) closed cavity is communicated with bypass valves through closed cavities. EFFECT: enhanced reliability of compressor due to mounting bypass valves in one plane. 3 dwg

Description

 The invention relates to compressors of gas turbine engines, including ground-based applications.

 A known compressor of a gas turbine engine with a device for ensuring gas-dynamic stability by bypassing part of the air from the flowing part through the holes using the bypass valve [1].

 A disadvantage of the known design is air bypass only because of one stage, which degrades the efficiency of the compressor and its reliability due to the deterioration of the radial diagram of the pressure field behind the air extraction stage.

 Closest to the claimed is a compressor, in which to obtain a more uniform pressure field behind the bypass stage, the bypass itself is carried out from two intermediate compressor stages [2].

 In the known design adopted as a prototype, air bypass is carried out behind two sequentially arranged intermediate stages of the compressor, which improves the radial diagram of the pressures at the outlet of these stages, however, this design is distinguished by large dimensions, weight and low reliability, since for installing valves that allow air to pass through from different steps, large-sized welded structures are required, prone to cracking, especially during long-term operation.

 The technical problem, which is aimed by the invention, is to improve the reliability of the compressor by installing valves in the same plane.

 The essence of the technical solution lies in the fact that in a gas turbine compressor containing a stator with a bypass casing and an inner casing, they form annular closed cavities connected at the inlet to the compressor flow part and at the outlet with bypass valves, according to the invention, the bypass valves are installed in one radial plane and successively alternate with each other in the circumferential direction, while the second annular closed cavity in the air flow is in communication with the bypass valves through the closed cavities.

 The installation of bypass valves in one radial plane, sequentially alternating between themselves in the circumferential direction, while the message of the second annular closed cavity along the air flow with the bypass valves through the closed cavities contributes to a more uniform selection of air around the circumference, i.e., circular uneven air flow in the flowing parts of the compressor after selection will be minimal, and allows the outer bypass housing to be made from a single piece without welding, which eliminates the appearance of cracks in orpuse, increasing the reliability of the compressor.

 Figure 1 shows a longitudinal section of a gas turbine compressor.

 Figure 2 is a longitudinal section of a compressor in another section.

 Figure 3 is a section aa in figure 2.

 The compressor 1 of the gas turbine engine consists of a rotor 2 and a stator 3, which in turn consists of an outer bypass body 4 and an inner body 5, in the latter working rings 6 and guide vanes rings 7 with guide vanes are fixed 8. For air bypass from the compressor flow part 9 1, holes 12 and 13 are made in the rings of the guide vanes 10 and 11 of the intermediate stages of the compressor in series, coaxial with the holes 14 and 15 in the inner housing 5. Since the cavities B and C are designed for air intake due to of exact compressor steps for boosting the oil supports and cooling the engine turbine (not shown), the bypass housing 4 is made with minimal dimensions: its length (along the compressor axis) is only not much larger than the diameter of the bypass valve mounting flange 16. To minimize the axial length of the bypass housing 4, the latter is made with radial ribs 18 and 19, as well as a flange 20, which together with the radial ribs 21 and 22 of the inner casing 5 form an annular cavity 23 of variable height h and an annular cavity 24, each of which at the input is connected with the compressor flow part 9 through openings 12, 14 and 13, 15, and at the outlet, the cavity 23 communicates directly with the bypass valves 17, and the cavity 24 communicates with the bypass valves 17 through the channels 25 and closed cavities 26. To eliminate circumferential unevenness when bypass air in the flow part of the compressor closed cavity 26 with valves 17 are placed evenly around the circumference. In this case, the bypass valves 17 communicating with the annular cavity 23 alternate in the circumferential direction with the bypass valves 17 communicating with the closed cavities 26. The increased hydraulic resistance during air bypass due to the flow of air through the openings 13, 15, the annular cavity 24, the channels 25 and closed cavities 26, is counteracted by the increased pressure of the bypassed air in comparison with the previous stage.

 The device operates as follows. When the engine is operating in transient conditions, to ensure gas-dynamic stability, to prevent surging and to reduce vibration stresses in the compressor blades, air is bypassed due to the intermediate stages of a multistage compressor into the atmosphere by opening the bypass valves 17, which are connected to the atmosphere at the outlet. Since the air bypass valves are installed in the same radial plane due to different stages, the axial dimensions of the bypass body 4 are minimal, which allows the body 4 to be made from a single piece without welding, which increases the reliability of the structure and eliminates cracks in the body 4. Alternating the circumference of the bypass valves due to different stages improves the circumferential uniformity of the air flow in the compressor flow path after the bypass stages, which reduces the vibration stresses of the compressor blades and increases its K PD.

Sources of information
1. S. A. Vyunov et al. Design and engineering of aircraft gas turbine engines. M.: Engineering, 1989, p. 56, Fig. 3.6.

 2. Technical description D30KU. M .: Engineering, 1975, pp. 36-37, Fig. 37-39 - prototype.

Claims (1)

 A gas turbine engine compressor containing a stator with a bypass housing and an inner housing, forming closed cavities between themselves, connected at the inlet to the compressor flow part, and at the outlet to bypass valves, characterized in that the bypass valves are installed in one radial plane and alternately alternate between in the circumferential direction, while the second annular closed cavity is in communication with the bypass valves through the closed cavities.

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