Ultra-compact wide speed range combined compressor structure

Abstract

The application discloses a super-compact wide-speed-range combined compressor structure and belongs to the field of auxiliary power devices.The structure comprises an axial flow rotor, variable-camber inlet adjustable guide vanes, a high-speed forward-swept centrifugal impeller, an integrated non-uniform consistency diffuser, a gear transmission device, a built-in starting and power generation integrated motor and an inner connecting ring; the key of the application lies in that the super-compact wide-speed-range combined compressor structure comprises the axial flow rotor, the variable-camber inlet adjustable guide vanes, the high-speed forward-swept centrifugal impeller, the integrated non-uniform consistency diffuser, the gear transmission device, the built-in starting and power generation integrated motor and the inner connecting ring.The combined compressor structure is compact, the component efficiency is high, and the stable working range is wide, so that the fuel consumption of the auxiliary power device is reduced, and the economy of the auxiliary power device is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of auxiliary power unit, and particularly relates to a super-compact wide-speed-range combined compressor structure. BACKGROUND

[0002] An auxiliary power unit (APU) is a small turbojet engine which has been widely used in military and civil aircrafts. The APU mainly provides compressed air for starting the main engine and the environmental control system of the aircraft. The working characteristics of the APU determine that the working range of the engine is large, so that the surge margin required by the centrifugal impeller is large. When the APU is in the bleed air mode, whether in the main engine starting mode or in the environmental control bleed air mode, the bleed air pressure is high to meet the working requirements, and the working point of the compressor is close to the surge boundary. At the same time, due to the unpredictable change of the bleed air amount, the outlet load changes, thereby causing the working point of the compressor to fluctuate. When the outlet air amount decreases, the working point may approach the surge boundary, and thus the surge may be caused. Since the main function of the auxiliary power unit is to bleed air, the outlet pressure of the bleed air is required to be maintained in a certain range regardless of the change of the outlet load. Unlike the surge control of the large engine, the bleed air cannot be discharged or the oil can not be cut to reduce the rotation and retreat the surge. Therefore, how to improve the surge margin of the centrifugal compressor as much as possible is an important research content of the compression system of the auxiliary power unit.

[0003] Most of the auxiliary power units adopt centrifugal impellers, but the centrifugal impeller has the disadvantages of large machining and assembly errors, large relative tip clearance and large boundary layer ratio, which easily leads to the problems of large weight, low efficiency and high specific fuel consumption of the compression system of the auxiliary power unit, and greatly limits the improvement of the performance of the aircraft. Therefore, it is urgent to propose a new super-compact compression system structure to realize the wide-speed-range and high-efficiency operation of the auxiliary power unit. SUMMARY

[0004] (I) The technical problem solved by the application is:

[0005] In order to overcome at least one defect of the prior art, break through the limit of the compression system and maximize the performance of the compression system of the auxiliary power unit, the application provides a super-compact wide-speed-range combined compressor structure to solve the problems of high specific fuel consumption and narrow stable working range of the auxiliary power unit.

[0006] (II) The technical scheme adopted by the application to solve the technical problem is:

[0007] The super-compact wide-speed-range combined compressor structure comprises an axial flow rotor, a variable camber inlet adjustable guide vane, a high-speed forward-swept centrifugal impeller, an integrated non-uniform consistency diffuser, a gear transmission device, a built-in starting and power generation integrated motor and an inner connecting ring.

[0008] The high-speed forward-swept centrifugal impeller is installed on the main shaft and can rotate synchronously with the main shaft, the gear transmission device is installed between the axial flow rotor and the high-speed forward-swept centrifugal impeller and is connected with the axial flow rotor and the high-speed forward-swept centrifugal impeller respectively, and the gear transmission device drives the axial flow rotor to rotate;

[0009] The variable-camber inlet adjustable guide vane is installed on the casing, and the integrated non-uniform solidity diffuser is arranged outside the high-speed forward-swept centrifugal impeller and is connected with the casing;

[0010] The built-in starting and power generation integrated motor is arranged behind the high-speed forward-swept centrifugal impeller and drives the main shaft to rotate, the inner connecting ring is arranged outside the gear transmission device, and the inner connecting ring, the axial flow rotor, the variable-camber inlet adjustable guide vane, the high-speed forward-swept centrifugal impeller and the inner wall of the casing form an air flow channel.

[0011] Preferably, the axial flow rotor has a turning angle of 10°-60°, the number of rotors is 30-60, and the total pressure ratio of the axial flow rotor is 1.5-3.

[0012] Preferably, the variable-camber inlet adjustable guide vane is formed by stacking three blade height sections, i.e., a blade root section, a middle blade section and a blade tip section.

[0013] The maximum blade thickness gradually decreases from the blade root section to the blade tip section, and the maximum blade thickness of the blade root section is 1.5-3 times the maximum blade thickness of the blade tip section or the middle blade section.

[0014] The variable-camber inlet adjustable guide vane is spaced apart from each other in the circumferential direction, and the number of the variable-camber inlet adjustable guide vanes is 6-30, the height of the variable-camber inlet adjustable guide vane is h, and the axial length is L, wherein 0.3

[0015] Preferably, the high-speed forward-swept centrifugal impeller comprises alternately distributed main blades and splitter blades, the main blades and the splitter blades both have a forward-swept characteristic, the amplitude of the forward-swept is 5%-20% of the chord length of the respective blade, and the tail edge of the splitter blade is flush with the tail edge of the main blade.

[0016] The forward edges of the main blades and the splitter blades are offset in the opposite direction of the rotation direction of the blades, and the offset amplitude is 5%-10% of the centrifugal impeller pitch, wherein the centrifugal impeller pitch is the distance between two adjacent centrifugal impellers.

[0017] A 0.5mm-1mm thick coating layer is coated on the casing corresponding to the main blades to reduce the assembly gap and avoid scraping and grinding during operation, and the coating material is silicone.

[0018] Preferably, the circumferential distance between adjacent blades of the integrated non-uniform solidity diffuser is inconsistent, and the ratio of the maximum distance to the minimum distance is 1.1-2.0.

[0019] The number of the integrated non-uniform consistency diffuser is 17-29, the wedge angle is 5-10°, the shape gradually changes from radial to axial, the integrated non-uniform consistency diffuser has a swallow-tail-shaped front trailing edge, is coated with an anti-fouling and anti-corrosion coating, and the inner wall of the wheel cover is smoothly connected with a round corner with a radius of 0.5-1.5 mm.

[0020] Preferably, the gear transmission device is a single-row or double-row planetary gear, power is branched through 3-5 planetary gears to ensure that the axial-flow rotor and the centrifugal impeller work at different rotating speeds and realize high-efficiency operation of the combined compressor rotor.

[0021] Preferably, the gear transmission device is cooled by cold air provided by the flow channel between the inner connecting ring and the high-speed forward-swept centrifugal impeller. This layout allows the gear box to be cooled in a compact and effective manner with lower complexity, which is beneficial to reduce the total weight of the compression system.

[0022] Preferably, the gear transmission device comprises a sun gear, a planetary gear, a planet carrier and a ring gear arranged coaxially, a plurality of planetary gears are arranged in the ring gear and rotate around the sun gear, the axis of each planetary gear is fixedly connected with the planet carrier through a connecting shaft, the plurality of planetary gears jointly drive one planet carrier, the sun gear drives the planetary gears using a central straight spur gear, a small amount of backlash exists between the central straight spur gear and the planetary gears to ensure correct meshing; each planetary gear meshes with the ring gear; the planetary gear, the planet carrier and the ring gear are power output ends and are connected with the centrifugal impeller; the sun gear is a power input end and is connected with the axial-flow rotor.

[0023] Preferably, the built-in starting and generating integrated motor drives the combined compressor structure and outputs electric power to the aircraft's environmental control system, and the electric power ranges from 20 kVA to 400 kVA.

[0024] (Three) Compared with the prior art, the combined compressor structure has the advantages that:

[0025] The combined compressor structure is compact in structure, high in component efficiency and wide in stable working range, which is beneficial to reduce the fuel consumption rate of the auxiliary power unit and improve the economy of the auxiliary power unit. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a schematic view of a super-compact wide-speed-range combined compressor;

[0027] Figure 2 is a schematic view of a gear transmission device;

[0028] Figure 3 is a schematic view of a variable-camber inlet adjustable guide vane;

[0029] Figure 4is a schematic view of a high-speed forward-swept centrifugal impeller;

[0030] Figure 5 is a schematic view of an integrated non-uniform solidity diffuser.

[0031] In the figure, 1-axial flow rotor, 2-variable curvature inlet adjustable guide vane, 3-high-speed forward-swept centrifugal impeller, 4-integrated non-uniform solidity diffuser, 5-gear transmission device, 6-embedded starting and power generation integrated motor, 7-inner connecting ring, 8-main blade, 9-split blade, 11-sun gear, 12-planet gear, 13-planet carrier, 14-ring gear. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical scheme and advantages of the present application clearer, the technical scheme in the embodiments of the present application will be described in more detail below with reference to the drawings in the embodiments of the present application. In the drawings, the same or similar notations represent the same or similar elements or elements having the same or similar functions throughout. The described embodiments are part of the embodiments of the present application, not all of the embodiments, and are intended to explain the present application, and cannot be understood as limiting the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0033] The present application aims to provide a super-compact wide-speed-range combined compressor structure to solve the problems of high fuel consumption and narrow stable working range of auxiliary power devices.

[0034] Specifically, the super-compact wide-speed-range combined compressor structure of the present application at least includes the following when implemented:

[0035] A super-compact wide-speed-range combined compressor structure includes an axial flow rotor 1, a variable curvature inlet adjustable guide vane 2, a high-speed forward-swept centrifugal impeller 3, an integrated non-uniform solidity diffuser 4, a gear transmission device 5, an embedded starting and power generation integrated motor 6, and an inner connecting ring 7.

[0036] The high-speed forward-swept centrifugal impeller 3 is installed on the main shaft and can rotate synchronously with the main shaft. The gear transmission device 5 is installed between the axial flow rotor 1 and the high-speed forward-swept centrifugal impeller 3 and is connected to the axial flow rotor 1 and the high-speed forward-swept centrifugal impeller 3, respectively. The gear transmission device 5 drives the axial flow rotor 1 to rotate.

[0037] The variable curvature inlet adjustable guide vane 2 is installed on the casing, and the integrated non-uniform solidity diffuser 4 is arranged outside the high-speed forward-swept centrifugal impeller 3 and connected to the casing.

[0038] The built-in starting and generating integrated motor 6 is arranged behind the high-speed forward-swept centrifugal impeller 3 and drives the rotation of the main shaft, the inner connecting ring 7 is arranged outside the gear transmission device 5, the inner connecting ring 7, the axial flow rotor 1, the variable-pitch inlet adjustable guide vane 2, the high-speed forward-swept centrifugal impeller 3 and the inner wall of the casing form an air flow channel.

[0039] Preferably, the axial flow rotor turning angle is 10°-60°, the number of rotors is 30-60, and the total pressure ratio of the axial flow rotor is 1.5-3.

[0040] Preferably, the variable-pitch inlet adjustable guide vane is formed by stacking three blade height sections, namely, a blade root section, a middle blade section and a blade tip section.

[0041] The maximum blade thickness gradually decreases from the blade root section to the blade tip section, and the maximum blade thickness of the blade root section is 1.5-3 times the maximum blade thickness of the blade tip section or the middle blade section.

[0042] The variable-pitch inlet adjustable guide vane is spaced apart from each other in the circumferential direction, and the number of the variable-pitch inlet adjustable guide vanes is 6-30, the height of the variable-pitch inlet adjustable guide vane is h, and the axial length is L, wherein 0.3

[0043] Preferably, the high-speed forward-swept centrifugal impeller comprises alternatingly distributed main blades and splitter blades, the main blades and the splitter blades both have a forward-swept characteristic, the amplitude of the forward-swept is 5%-20% of the chord length of the respective blade, and the tail edge of the splitter blade is flush with the tail edge of the main blade.

[0044] The forward edges of the main blades and the splitter blades are offset in the opposite direction of the rotation direction of the blades, and the offset amplitude is 5%-10% of the centrifugal impeller pitch, wherein the centrifugal impeller pitch is the distance between two adjacent centrifugal impellers.

[0045] The main blades correspond to a 0.5mm-1mm thick coating layer on the casing to reduce the assembly gap and avoid scraping during operation, and the coating material is silicone.

[0046] Preferably, the circumferential distance of adjacent blades of the integrated non-uniform solidity diffuser is inconsistent, and the ratio of the maximum distance to the minimum distance is 1.1-2.0.

[0047] The number of the integrated non-uniform solidity diffusers is 17-29, the wedge angle is 5-10°, the shape gradually changes from radial to axial, the integrated non-uniform solidity diffuser has a dovetail-shaped front tail edge, is coated with an anti-fouling and anti-corrosion coating layer, and the inner wall of the wheel cover is smoothly transitioned with a round corner with a radius of 0.5-1.5mm.

[0048] Preferably, the gear transmission is a single-row or double-row planetary gear, power is split by 3-5 planetary gears, ensuring that the axial flow rotor and the centrifugal impeller work at different rotating speeds, and realizing high-efficiency operation of the combined compressor rotor.

[0049] Preferably, the gear transmission is cooled by cold air provided by a flow channel between the inner connecting ring and the high-speed forward-swept centrifugal impeller. This layout allows the gear box to be cooled in a compact and effective manner with lower complexity, which is advantageous for reducing the total weight of the compression system.

[0050] Preferably, the gear transmission comprises a sun gear 11, planetary gears 12, a planet carrier 13 and a ring gear 14 arranged coaxially, a plurality of planetary gears 12 are arranged in the ring gear 14 and rotate around the sun gear 11 in a planetary manner, the axis of each planetary gear 12 is fixedly connected to the planet carrier 13 through a connecting shaft, a plurality of planetary gears 12 jointly drive one planet carrier 13, the sun gear 11 drives the planetary gears 12 using a central straight spur gear, and a small amount of backlash exists between the central straight spur gear and the planetary gears 12 to ensure correct meshing; each planetary gear 12 meshes with the ring gear 14; the planetary gears 12, the planet carrier 13 and the ring gear 14 are power output ends and are connected to the centrifugal impeller; and the sun gear 11 is a power input end and is connected to the axial flow rotor.

[0051] Preferably, the built-in starting and generating integrated motor drives the combined compressor structure and outputs electric power to the aircraft's environmental control system, and the electric power ranges from 20kVA to 400kVA.

[0052] Preferably, the working principle of the combined compressor is that the built-in starting and generating integrated motor drives the high-speed forward-swept centrifugal impeller, and then drives the axial flow rotor through the gear transmission device at a deceleration ratio, so that air flows through the axial flow rotor, the variable-camber inlet adjustable guide vane, the high-speed forward-swept centrifugal impeller and the integrated non-uniform solidity diffuser in sequence, which has the advantages of high component efficiency and wide stable working range, and is advantageous for reducing the fuel consumption rate of the auxiliary power unit and improving the economy.

[0053] The above embodiments completely and effectively achieve the purpose of the present application. Those skilled in the art can understand that the present application includes but is not limited to the contents described in the drawings and the above specific embodiments. Although the present application has been described with respect to the presently preferred and most advantageous embodiments, it should be understood that the present application is not limited to the disclosed embodiments, and any modification that does not deviate from the functional and structural principles of the present application will be included in the scope of the claims.

Claims

1. An ultra-compact wide speed range combined compressor structure, characterized in that, The structure comprises an axial flow rotor, variable curvature inlet adjustable guide vanes, a high-speed forward-swept centrifugal impeller, an integrated non-uniform solidity diffuser, a gear transmission device, an integrated start-generating motor and an inner connecting ring. The high-speed forward-swept centrifugal impeller is installed on the main shaft and can rotate synchronously with the main shaft, the gear transmission device is installed between the axial flow rotor and the high-speed forward-swept centrifugal impeller and is connected with the axial flow rotor and the high-speed forward-swept centrifugal impeller respectively, and the gear transmission device drives the axial flow rotor to rotate. The variable curvature inlet adjustable guide vanes are installed on the casing, and the integrated non-uniform solidity diffuser is arranged outside the high-speed forward-swept centrifugal impeller and is connected with the casing. The integrated start-generating motor is arranged behind the high-speed forward-swept centrifugal impeller and drives the main shaft to rotate, and the inner connecting ring is arranged outside the gear transmission device, and the inner connecting ring, the axial flow rotor, the variable curvature inlet adjustable guide vanes, the high-speed forward-swept centrifugal impeller and the inner wall of the casing form an air flow channel. The gear transmission device is cooled by cold air provided by the flow channel between the inner connecting ring and the high-speed forward-swept centrifugal impeller.

2. An ultra-compact combined compressor structure of wide speed range according to claim 1, characterized in that, The axial flow rotor has a turning angle of 10°-60°, the number of rotors is 30-60, and the total pressure ratio of the axial flow rotor is 1.5-3.

3. The ultra-compact combined compressor structure of a wide speed range according to claim 1, characterized in that, The variable curvature inlet adjustable guide vanes are formed by stacking three blade height sections, namely, a blade root section, a middle blade section and a blade tip section. The maximum blade thickness of the blade root section gradually decreases to the maximum blade thickness of the blade tip section, and the maximum blade thickness of the blade root section is 1.5 times the maximum blade thickness of the blade tip section or the middle blade section 3 times; The variable curvature inlet adjustable guide vanes are spaced from each other in the circumferential direction, the number of the variable curvature inlet adjustable guide vanes is 6-30, the height of the variable curvature inlet adjustable guide vanes is h, and the axial length is L, wherein 0.3 4. The ultra-compact combined wide speed range compressor structure according to claim 1, wherein The high-speed forward-swept centrifugal impeller comprises alternately distributed main blades and splitter blades, the main blades and the splitter blades both have a forward-swept characteristic, the amplitude of the forward-swept is 5%-20% of the chord length of the respective blades, and the tail edge of the splitter blades is flush with the tail edge of the main blades. The front edges of the main blades and the splitter blades are offset in the opposite direction of the rotation direction of the blades, and the offset amplitude is 5%-10% of the centrifugal impeller pitch, wherein the centrifugal impeller pitch is the distance between two adjacent centrifugal impellers. A 0.5mm-1mm thick coating is coated on the casing corresponding to the main blades to reduce the assembly gap and avoid scraping and grinding during operation, and the coating material is silicone resin.

5. The ultra-compact combined wide speed range compressor structure according to claim 1, wherein The circumferential distance of adjacent blades of the integrated non-uniform solidity diffuser is not consistent, and the ratio of the maximum distance to the minimum distance is 1.1-2.

0. The number of the integrated non-uniform solidity diffusers is 17-29, the wedge angle is 5-10°, the shape gradually changes from radial to axial, the integrated non-uniform solidity diffuser has a dovetail-shaped front tail edge, is coated with an anti-fouling and anti-corrosion coating, and the inner wall of the wheel cover is smoothly transitioned with a round corner with a radius of 0.5-1.5mm.

6. The ultra-compact combined wide speed range compressor structure according to claim 1, wherein The gear transmission device is a single-row or double-row planetary gear, power is branched through 3-5 planetary gears to ensure that the axial flow rotor and the centrifugal impeller work at different speeds and realize high-efficiency operation of the combined compressor rotor.

7. An ultra-compact combined compressor structure of wide speed range according to claim 6, characterized in that, The gear transmission device comprises a sun gear, a planet gear, a planet carrier and a ring gear arranged coaxially, a plurality of planet gears are arranged in the ring gear and perform planetary rotation around the sun gear, the axis of each planet gear is fixedly connected with the planet carrier through a connecting shaft, the plurality of planet gears jointly drive one planet carrier, the sun gear drives the planet gear, and a small amount of tooth gap exists between the sun gear and the planet gear to ensure correct meshing; Each planet gear is meshed with the ring gear; the planet gear, the planet carrier and the ring gear are power input ends and are connected with a centrifugal impeller; the sun gear is a power output end and is connected with an axial flow rotor.

8. The ultra-compact combined wide speed range compressor structure according to claim 1, wherein, The built-in starting and generating integrated motor drives the combined compressor structure and outputs electric power to the aircraft's environmental control system, and the electric power range is 20kVA~400kVA.

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