CN117432650A - Multi-stage bleed air compressor for variable cycle engine - Google Patents

Abstract

The invention discloses a multi-stage bleed air compressor for a variable cycle engine, which comprises annular bleed air adjusting mechanisms respectively positioned at the inner shells of the compressors corresponding to second-stage, third-stage, fourth-stage and fifth-stage fixed guide vanes of the multi-stage bleed air compressor; each annular deflation adjusting mechanism is associated with two stages of movable blades which are adjacent front and back and one stage of stationary blade between the two movable blades, and comprises a motor gear, an outer gear ring, a deflation port group, a rotary shell and an inner side shell; the annular air release adjusting mechanism adopts the motor to drive the gear to dynamically adjust the area of the air release passage, so that the air release flexibility of the whole machine in different flight states is met, the accurate air release control can be realized, and the multi-mode switching requirement of the variable-cycle engine can be stably supported.

Description

Multi-stage bleed air compressor for variable cycle engine

Technical Field

The invention relates to the field of aero-engine compressor design, and particularly provides a variable-cycle engine compressor with a multi-stage air release mechanism.

Background

With the proposal of advanced engine concept, a variable cycle engine capable of realizing multi-state switching by adjusting the geometric configuration of a characteristic structure becomes a mainstream concept scheme, but the variable cycle engine has the characteristics of full envelope performance, inevitably causes the problems of compact engine layout, high pneumatic load of a compressor part, high performance matching difficulty of a rotating part and the like, and the problems provide new challenges for the design of a high-pressure compressor of the variable cycle engine.

The wide operating range of variable cycle engines induces multiple transition state (acceleration or deceleration) operating demands such that the compressor does not always operate at design conditions, and as operating conditions change, the operating point tends to deviate from the design point, and unstable compressor flow occurs under certain conditions. The pneumatic instability of the compressor is generally divided into surge, blockage and stall, and the flow change is a direct cause of the three pneumatic instabilities. When the flow rate of the air compressor is increased or the flow rate is high, the axial speed of the air is increased, the attack angle of the air flow entering the movable blade is reduced, the air flow separation of the movable blade basin occurs along with the increase of the negative attack angle, the supercharging efficiency of the air compressor is suddenly reduced, and the performance is attenuated until the air is blocked; when the flow of the compressor is reduced or the flow is low, the axial speed of the gas is reduced, the attack angle of the gas flow entering the movable blade is increased, and the back of the movable blade is subjected to gas flow stall separation along with the increase of the positive attack angle, so that rotating stall or surge is often generated.

In order to widen the stable range of the compressor, the compressor is generally designed by adopting the means of casing design, adjustable inlet guide vanes, adjustable stationary vanes, interstage bleed and the like. The adjustable guide vane controls the air outlet angle of the guide vane by rotating the inlet guide vane, so that the air flow attack angle of the inflow moving vane of the next stage is in a normal angle. The interstage bleed is to adjust the gas flow of the compressor by placing gas from the interstage position of the compressor so as to achieve the purpose of increasing the stable working margin.

In order to solve the problem of instability of the air flow of the compressor of the variable cycle engine, the Chinese patent application with the publication number of CN114017387A discloses an air guiding structure of the compressor of the aeroengine, wherein an air guiding hole of the final stage of the compressor is arranged at the position of the final stage of the high-pressure compressor, and air in the compressor is guided into an engine outer duct runner through an air discharging connector, an air guiding pipeline, an air discharging control device and an expanding exhaust pipeline in sequence, so that the working stability range of the compressor is improved. However, the structure is mainly used for final stage air-entraining, and meanwhile, an arrangement space needs to be reserved for an expanding exhaust pipe path, so that the structure has certain use limitation under the compact layout requirement of a variable cycle engine. Chinese patent application publication No. CN112797027a discloses a compressor and a deflation mechanism thereof, wherein a plurality of baffles are connected by a plurality of pinions and then meshed with a large gear ring, and the plurality of baffles are driven to synchronously rotate by the plurality of pinions, so as to realize opening and closing of a deflation channel. The pinion is driven by the large gear, and the plurality of pinions are linked with the plurality of baffles by the rotating shaft to indirectly drive the baffles, so that the energy transmission path is prolonged, the whole structure is relatively complex, and the deflation speed of the compressor is difficult to ensure.

Therefore, when the existing compressor design with the air release requirement performs air release action, the structure needing linkage is more, the working reliability is lower under the variable-cycle multi-mode requirement, and the quick matching with the overall performance conversion of the variable-cycle engine is difficult to realize, so that the surge risk is reduced.

Disclosure of Invention

In order to solve the technical problems, the invention provides the compressor for the variable cycle engine with the multi-stage air release mechanism, which can reduce the surge risk and enlarge the stable working range of the whole engine by directly releasing air and adjusting the compressor flexibly and reliably under the limited duct space of the variable cycle engine.

The complete technical scheme of the invention comprises the following steps:

the multistage bleed air compressor comprises four annular bleed air adjusting mechanisms, wherein the four annular bleed air adjusting mechanisms are respectively positioned at the inner shells of the compressors corresponding to the second stage, the third stage, the fourth stage and the fifth stage of the multistage bleed air compressor; each annular deflation adjusting mechanism is associated with two stages of movable blades which are adjacent front and back and one stage of stationary blade between the two movable blades;

the annular deflation adjusting mechanism comprises a motor gear, an outer gear ring, a deflation port group, a rotary shell and an inner side shell;

an external motor is fixed on the outer casing of the air compressor, a gear of the external motor is meshed with an external gear, the external gear and an annular air release belt are integrally formed and jointly form a rotary shell, and an external air release opening is formed in the annular air release belt. The rotary shell is internally provided with an inner shell, the inner shell is provided with an inner air discharge port, the inner air discharge port and the outer air discharge port form an air discharge port group together, the inner air discharge port and the outer air discharge port are uniformly distributed in the circumferential direction of the shell respectively and are consistent in number, the overlapped parts of the inner air discharge port and the outer air discharge port form an air compressor air discharge channel, and the area of the air compressor air discharge channel is determined by the relative positions of the outer air discharge port positioned on the rotary shell and the inner air discharge port positioned on the inner shell.

Further, the outer gear ring is capable of circumferential rotational movement about the engine axis and changes the bleed passage area of the compressor upon actuation of an external motor.

Further, the external motor is fixed at a position downstream of the air release port of the external case.

Further, a sealing strip is arranged between the outer rotary shell and the inner casing shell of the compressor along the axial direction.

Further, when the high-pressure air compressor stops discharging, the sealing strips rotate together along with the rotation of the rotary shell until the air discharging opening of the outer shell and the air discharging opening of the inner shell are completely misplaced, so that the circumferential sealing of the air compressor is realized.

Further, the compression system of the variable cycle engine comprises a front fan, a rear fan, a core driving fan and a high-pressure air compressor, and the variable cycle engine further comprises a first outer duct, a second outer duct and a third outer duct.

Further, in the flying process of the variable cycle engine, when the folding rotational speed of the high-pressure compressor is rapidly reduced and the folding flow of the inlet is rapidly reduced, the air release devices corresponding to the fourth-stage moving blade and the fifth-stage moving blade of the high-pressure compressor are adjusted as follows: the motor gear drives the outer gear ring, and then the relative position of the outer air discharge port and the inner air discharge port is adjusted through the rotation of the rotary shell connected with the outer gear ring, so that the flow area of the air discharge port group is increased, the gas at the adjacent positions of the four-stage stationary blade and the five-stage stationary blade of the high-pressure compressor is discharged to the first outer duct through the air discharge port group, and the air in the first outer duct is discharged after being mixed.

Furthermore, when the variable cycle engine flies from low altitude to high altitude, when the incoming flow temperature is reduced, the air mass flow is reduced under the condition of unchanged design rotating speed, and the air release devices corresponding to the second-stage movable blades and the third-stage movable blades of the high-pressure air compressor are adjusted. And discharging the gas at the adjacent positions of the second-stage static blades and the third-stage static blades of the high-pressure compressor to the first outer duct through the air discharge port group, and discharging the mixed air in the first outer duct.

Compared with the prior art, the invention has the following main advantages:

1. the motor driving gear is adopted to dynamically adjust the area of the air release passage, and the motor is fixed on the compressor casing, so that the structure is compact, and the performance is stable.

2. The high-pressure air compressor adopts a multi-stage gear driving air release mode, and can realize accurate air release control while meeting the air release flexibility of the whole machine in different flight states. When the folded flow of the inlet of the high-pressure compressor is reduced, the rotation angles of the three interstage bleed belts are dynamically controlled through a preset gear rotation rule, so that the compressor is always far away from a surge boundary, and the multi-mode switching requirement of the variable-cycle engine can be stably supported.

3. By arranging the multi-stage circumferentially uniform air release openings, the mixing loss of the outer culvert can be reduced. The flexible rotary shell adjusting method is matched with the number and the area of the circumferential air discharge ports, so that the mixing loss of the high-pressure gas of the compressor and the low-temperature low-pressure gas of the outer duct can be effectively reduced when the high-pressure gas of the compressor is discharged to the first outer duct of the variable cycle engine.

4. The motor gear-outer gear meshing driving mode is adopted, the structure is relatively simple, the weight ratio of the compressor is reduced, and meanwhile, the cost is low and the maintenance is convenient.

Drawings

Fig. 1 is a schematic diagram of a variable cycle engine compressor arrangement.

Fig. 2 is a schematic view of the mounting position of the bleed belt of the high pressure compressor.

FIG. 3 is a schematic view of the structure of the inter-stage bleed belt of the compressor.

FIG. 4 is an axial schematic view of an inter-compressor stage bleed belt.

Fig. 5 is a schematic perspective view of an inter-compressor stage bleed belt.

FIG. 6 is a schematic cross-sectional view of an inter-compressor stage bleed belt.

Wherein, 1-front fan, 2-rear fan, 3-core drive fan, 4-high pressure compressor, 5-first outer duct, 6-second outer duct, 7-third outer duct, 8-annular air bleed, 9-motor gear, 10-outer gear ring, 11-bleed port set, 12-rotating housing, 13-inner housing, 14-compressor hub, 15-compressor front moving blade, 16-compressor stationary blade, 17-outer bleed port, 18-inner bleed port, 19-compressor rear moving blade, 20-engine axis.

Detailed Description

The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings, and it is obvious that the described embodiments are only illustrative and not limiting of the present application.

A multistage bleed air compressor for a variable cycle engine comprises a multistage rotor blade, a compressor hub, a compressor casing and the like which form a high-pressure compressor component. As shown in fig. 1, the compression system of the variable cycle engine includes a front fan 1, a rear fan 2, a core drive fan 3, and a high pressure compressor 4. Wherein a first outer duct 5, a second outer duct 6, a third outer duct 7, and a high pressure compressor bleed 8 are also provided at the relevant locations.

Because the high-pressure compressor of the variable cycle engine is connected with the high-pressure turbine through the high-pressure shaft, the air flow at the outlet of the core driving fan is further pressurized so as to meet the air pressure requirement at the inlet of the combustion chamber. The variable cycle engine is switched to a sub-patrol flight state rapidly by closing the interstage combustion chamber from a high-speed super-patrol state, and in the process, the folding rotation of the compressor is reduced rapidly, and the relative folding flow is also reduced rapidly, so that the design of the high-pressure compressor needs to consider the high surge margin capacity under the low folding flow. The multistage adjustable guide vane is adopted, the guide vane adjustment mode is carried out through the connecting rod structure, the structural complexity and the overall weight are often increased, a large expansion space is reserved for the device through the design of the expansion type air-entraining flow path of the air-entraining joint, the applicability is low under a variable circulation background, the multi-stage gear linkage baffle plate mode is adopted, multiple independent structure matching is needed, and the working reliability is low.

Therefore, the invention designs the high-pressure compressor air release device 8 for the variable cycle engine, which is totally 4 sets, and is respectively arranged at the positions of the inner shells of the compressors corresponding to the second, third, fourth and fifth stages of fixed guide vanes, as shown in fig. 2, and is an annular air release adjusting mechanism driven by a motor gear to rotate.

As shown in fig. 3-4, each collar-shaped deflation adjustment mechanism comprises a motor gear 9, an outer gear ring 10, a deflation port group 11, a swivel housing 12 and an inner housing 13. Wherein the front moving blades 15, the rear moving blades 19 and the stator blades 16 of the high-pressure compressor are arranged on the compressor hub 14. Thus, a collar-shaped bleed air adjustment mechanism involves two stages of blades adjacent one another in front of the other and one stage of vanes between the two.

As shown in fig. 5 to 6, the discharge passage area of the compressor is determined by an outer discharge port 17 provided on the rotary casing 12 and an inner discharge port 18 provided on the inner casing 13. Wherein the inner bleed ports and the outer bleed ports are evenly distributed in the circumferential direction of the casing around the compressor axis 20 and are uniform in number.

The external motor is fixed on the outer casing of the air compressor, the motor driving gear is meshed with the outer gear ring, and the outer gear ring performs circumferential rotary motion around the axis of the engine. The annular air release belt with the air release opening and the outer gear ring adopt an integrated design to form an air release rotary outer shell, the rotary outer shell rotates along the axis along with the action of a motor driving gear, and the area of an air release channel formed by the outer air release opening dynamically rotated by the outer shell and the inner air release opening at the fixed position of the inner shell of the air compressor is reduced until the whole air release channel is closed. The external air discharge ports on the annular air discharge belt are uniformly distributed along the circumferential direction of the rotary shell and are completely consistent with the number and geometry of the internal air discharge ports on the high-pressure compressor casing. In a variable cycle engine design, the high pressure compressor without any actuating mechanism and with the interstage annular bleed belt can adopt a fixed guide vane design, so that the structural complexity is reduced. The air discharge flow is controllable by arranging inner air discharge ports at the adjacent positions of the roots of the 2, 3, 4 and 5 stages of guide vanes of the high-pressure air compressor and dislocation generated by the outer air discharge ports of the rotary shell. The number of the air release ports can be dynamically adjusted according to the flow demand.

In order to improve the tightness of the high-pressure compressor in a non-deflation state, an axial sealing strip is arranged between the outer rotary shell and the inner casing shell of the compressor. The sealing strip is fixed on the outer side rotary shell, and when the high-pressure compressor stops discharging, the sealing strip rotates together with the rotation of the rotary shell until the outer side shell discharging port and the inner side shell discharging port are completely misplaced, so that the circumferential sealing of the compressor is realized.

The motor drive gear that nimble gassing set up, with external gear engagement's outer ring gear, with the rotatory shell of outer ring gear integrative cast compressor and the controllable relief vent of area for become the circulation engine and keep away from the compressor surge boundary under the multi-state, through gear-ring gear engagement driven flow regulation, satisfy the multistage gassing demand of compressor, promoted the gassing flexibility, reduced the surging risk.

The multistage bleed compressor of the present invention can have two operating states:

1. in the flying process of the variable cycle engine, when the folding rotational speed of the high-pressure air compressor is rapidly reduced and the folding flow of the inlet is rapidly reduced, the flow coefficient of each level of the high-pressure air compressor is reduced from the front level to the rear level more and less. In this case, the flow coefficient of the first several stages of the high-pressure compressor is lower than the design value, the flow coefficient of the middle several stages is close to the design value, and the flow coefficient of the latter stages is larger than the design value. The vane air inlet triangle is characterized in that the front stages have larger positive attack angles, the front stages are close to a surge boundary and even surge occurs, and the rear stages have larger negative attack angles and even airflow blockage occurs. At the moment, the air release devices corresponding to the fourth-stage moving blades and the fifth-stage moving blades of the high-pressure air compressor are adjusted. The motor gear 9 drives the outer gear ring 10, and then the relative space position of the outer air discharge opening 17 and the inner air discharge opening 18 is regulated through the rotation of the rotary shell 12 connected with the outer gear ring, so that the flow area of the air discharge opening group 11 is increased, the air at the adjacent positions of the four-stage stationary blade and the five-stage stationary blade of the high-pressure compressor is discharged to the first outer duct 7 through the air discharge opening group 11, the air in the first outer duct is discharged after being mixed, and the problem of front asthma and rear blockage faced by the high-pressure compressor is rapidly eliminated.

2. The variable cycle engine reduces the incoming flow temperature when flying from low altitude to high altitude, the air mass flow is reduced under the condition of unchanged design rotating speed, the flow passage gas has continuously increased positive attack angle at the front stages of the gas compressor, the blade backs of the gas are separated, and the front stages have airflow blockage. At the moment, the air release devices corresponding to the second-stage and third-stage movable blades of the high-pressure air compressor are adjusted. The gas at the adjacent positions of the second-stage and third-stage stationary blades of the high-pressure compressor is discharged to the first outer duct 7 through the air discharge port group 11, and the air in the first outer duct is discharged after being mixed, so that the problem of front blockage and rear asthma faced by the high-pressure compressor is rapidly eliminated.

The foregoing description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and any simple modification, variation and equivalent structural changes made to the above embodiment according to the technical substance of the present invention still fall within the scope of the technical solution of the present invention.

Claims (8)

1. The multistage bleed air compressor for the variable cycle engine is characterized by comprising four annular bleed air adjusting mechanisms, wherein the four annular bleed air adjusting mechanisms are respectively positioned at the inner shells of the compressors corresponding to the second stage, the third stage, the fourth stage and the fifth stage of fixed guide vanes of the multistage bleed air compressor; each annular deflation adjusting mechanism is associated with two stages of movable blades which are adjacent front and back and one stage of stationary blade between the two movable blades;

the annular deflation adjusting mechanism comprises a motor gear, an outer gear ring, a deflation port group, a rotary shell and an inner side shell;

an external motor is fixed on the outer casing of the air compressor, a gear of the external motor is meshed with an external gear, the external gear and an annular air release belt are integrally formed and jointly form a rotary shell, and an external air release port is arranged on the annular air release belt; the rotary shell is internally provided with an inner shell, the inner shell is provided with an inner air discharge port, the inner air discharge port and the outer air discharge port form an air discharge port group together, the inner air discharge port and the outer air discharge port are uniformly distributed in the circumferential direction of the shell respectively and are consistent in number, the overlapped parts of the inner air discharge port and the outer air discharge port form an air compressor air discharge channel, and the area of the air compressor air discharge channel is determined by the relative positions of the outer air discharge port positioned on the rotary shell and the inner air discharge port positioned on the inner shell.

2. A multi-stage bleed air compressor for a variable cycle engine as defined in claim 1 wherein said outer teeth are capable of circumferential rotational movement about the engine axis and change the bleed passage area of the compressor upon actuation of an external motor.

3. A multi-stage bleed compressor for a variable cycle engine as defined in claim 1, wherein the external electric motor is fixed at a location downstream of the outer casing bleed port.

4. A multistage bleed air compressor for a variable cycle engine according to claim 1 or 2, wherein a seal is provided axially between the outer rotary casing and the inner casing of the compressor.

5. The multistage bleed air compressor for a variable cycle engine of claim 4, wherein when the high pressure air compressor stops bleeding, the seal strips rotate together with the rotation of the rotary housing until the outer bleed port of the outer housing is completely displaced from the inner bleed port of the inner housing, thereby achieving a circumferential seal of the air compressor.

6. A variable cycle engine with a compressor as defined in any one of claims 1-5, wherein the compression system of the variable cycle engine comprises a front fan, a rear fan, a core drive fan, a high pressure compressor, the variable cycle engine further comprising a first outer duct, a second outer duct, and a third outer duct.

7. The variable cycle engine of claim 6, wherein during the flight of the variable cycle engine, when the folding rotational speed of the high pressure compressor is rapidly reduced and the inlet folding flow is rapidly reduced, the bleed devices corresponding to the fourth and fifth stage moving blades of the high pressure compressor are adjusted as follows: the motor gear drives the outer gear ring, and then the relative position of the outer air discharge port and the inner air discharge port is adjusted through the rotation of the rotary shell connected with the outer gear ring, so that the flow area of the air discharge port group is increased, the gas at the adjacent positions of the four-stage stationary blade and the five-stage stationary blade of the high-pressure compressor is discharged to the first outer duct through the air discharge port group, and the air in the first outer duct is discharged after being mixed.

8. A variable cycle engine as defined in claim 6, wherein the variable cycle engine is adapted to reduce the air mass flow rate when the incoming flow temperature is reduced during low-altitude to high-altitude flight, and wherein the air mass flow rate is reduced at a constant design speed by adjusting the bleed devices associated with the second and third stage buckets of the high pressure compressor. And discharging the gas at the adjacent positions of the second-stage static blades and the third-stage static blades of the high-pressure compressor to the first outer duct through the air discharge port group, and discharging the mixed air in the first outer duct.