Mixed-flow type gas compressor

Abstract

The utility model discloses a mixed-flow compressor. At present, due to the adoption of a two-stage centrifugal compressor, the efficiency is reduced due to too many turning of a flow channel, and meanwhile, complexity is caused when double shafts are adopted. The multi-stage centrifugal air compressor comprises a multi-stage axial flow air compressor A and a single-stage centrifugal air compressor B, wherein the multi-stage axial flow air compressor and the single-stage centrifugal air compressor share the same rotor; the multi-stage axial-flow compressor comprises an air inlet chamber, an axial-flow compressor casing and a compressor rotor, a plurality of groups of axial-flow compressor moving blades are fixed on the outer ring surface of the compressor rotor, a plurality of groups of compressor guide blade assemblies are fixed in the axial-flow compressor casing, and the axial-flow compressor moving blades and the compressor guide blade assemblies are arranged at intervals; a plurality of groups of rotor wheel discs are fixed in the compressor rotor; the centrifugal wheel disc of the single-stage centrifugal compressor is connected with the last-stage rotor wheel disc of the multi-stage axial flow compressor through a flange; and the centrifugal compressor casing is connected with the axial flow compressor casing through a flange. The utility model is applied to the mixed-flow compressor.

Description

Technical Field

[0001] The utility model relates to a mixed flow compressor. Background Art

[0002] As the compression ratio of compressors for small and medium-flow engines and gas turbines increases, the channel height of the subsequent stages becomes increasingly smaller. If the entire compressor utilizes axial-flow stages, the efficiency of the subsequent stages will be very low. For two-stage centrifugal compressors, the excessive flow path bends will lead to reduced efficiency, and the use of two shafts will also cause complex issues. Utility Model Content

[0003] The purpose of the utility model is to solve the above-mentioned problems, thereby providing a mixed flow compressor.

[0004] The above purpose is achieved through the following technical solutions:

[0005] A mixed flow compressor comprises a multi-stage axial flow compressor and a single-stage centrifugal compressor, wherein the multi-stage axial flow compressor and the single-stage centrifugal compressor share the same rotor;

[0006] The multi-stage axial flow compressor includes an air inlet chamber, an axial flow compressor casing, and a compressor rotor. Multiple sets of axial flow compressor rotor blades are fixed on the outer annular surface of the compressor rotor. Multiple sets of compressor guide vane assemblies are fixed in the axial flow compressor casing. The axial flow compressor rotor blades and the compressor guide vane assemblies are arranged at intervals.

[0007] The single-stage centrifugal compressor comprises a centrifugal impeller, an impeller cover, a centrifugal compressor casing and a centrifugal wheel;

[0008] Multiple sets of rotor discs are fixed in the compressor rotor, and the centrifugal discs of the single-stage centrifugal compressor are connected to the rotor discs of the last stage of the multi-stage axial flow compressor via flanges;

[0009] The centrifugal compressor casing is connected to the axial flow compressor casing via a flange.

[0010] The mixed flow compressor, the single-stage centrifugal compressor includes a centrifugal impeller, an impeller cover, a centrifugal compressor casing and a centrifugal wheel disc, the centrifugal impeller is fixed on the centrifugal wheel disc, the impeller cover and the centrifugal impeller are gap-fitted, the impeller cover and the centrifugal compressor casing are fixed by bolts, and the impeller cover mating surface is provided with a labyrinth sealing tooth structure.

[0011] The mixed flow compressor described above, wherein the compressor guide vane assembly includes an outer ring, compressor stator blades, an inner ring and an air seal arc; the outer ring is provided with dovetail grooves, the number of dovetail grooves on each stage of the outer ring is equal to the number of compressor stator blades, and the compressor stator blades are fixed to the dovetail grooves; the air seal arc is connected to the inner ring; the inner ring and the compressor stator blades are fixed with rivets, and the outer ring is circumferentially inserted into a matching groove opened in the compressor casing.

[0012] In the mixed flow compressor, the compressor rotor is in the form of a drum, the compressor rotor is connected to the first-stage / last-stage rotor disc via a flange, and is welded to the intermediate-stage disc via an electron beam.

[0013] In the mixed flow compressor, the compressor casing comprises a guide vane casing and an intermediate casing, and the vane casing and the intermediate casing are connected by bolts.

[0014] In the mixed flow compressor, the axial flow compressor rotor blades and the axial flow compressor casing are clearance-matched, and the clearance d is 0.3-0.5 mm.

[0015] In the mixed flow compressor, the compressor rotor is provided with a labyrinth seal tooth structure, and the labyrinth seal teeth form a seal together with the air seal arc.

[0016] In the mixed flow compressor, the axial flow compressor moving blades and the compressor stationary blades are both titanium alloy blades.

[0017] Beneficial effects:

[0018] 1. The utility model adopts a mixed flow compressor combining axial flow and centrifugal flow, which can combine the characteristics of smooth flow path, high efficiency, and adaptability to large inlet flow of the axial flow stage and the characteristics of adaptability to small flow, wide working range, few parts and high reliability of the centrifugal stage.

[0019] 2. The utility model is used for a mixed flow multi-stage compressor of a gas turbine, which can achieve a high pressure ratio and high efficiency at a small flow rate. The axial flow compressor and the centrifugal compressor share a rotor, and the overall structure is simple, easy to process, and suitable for popularization and use. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural diagram of the utility model;

[0021] Figure 2 It is a structural diagram of a multi-stage axial flow compressor;

[0022] Figure 3 It is a structural diagram of a single-stage centrifugal compressor;

[0023] Figure 4It is a structural diagram of the compressor guide vane assembly;

[0024] Figure 5 It is a schematic diagram of the labyrinth seal tooth structure of the compressor rotor;

[0025] Figure 6 This is a schematic diagram of the gap between the axial flow compressor blades and the axial flow compressor casing;

[0026] Figure 7 It is a structural diagram of the axial flow compressor casing;

[0027] Figure 8 It is a schematic diagram of the connection between the centrifugal wheel and the rotor wheel;

[0028] Figure 9 It is a schematic diagram of the structure of the diffuser section of a single-stage centrifugal compressor;

[0029] Figure 10 It is a schematic diagram of the blade diffuser structure;

[0030] Figure 11 yes Figure 3 Magnified view of part C;

[0031] In the figure: A. multi-stage axial compressor; B. single-stage centrifugal compressor; 1. air inlet chamber; 2. axial compressor casing; 3. compressor rotor; 4. inlet guide vane; 5. axial compressor moving blade; 6. compressor guide vane assembly; 7. rotatable guide vane; 8. rotor wheel; 10. centrifugal wheel; 11. centrifugal impeller; 12. impeller cover; 13. centrifugal compressor casing; 14. diffuser; 15. outlet guide vane assembly; 16. back seal; 21. outer ring; 22. compressor stator; 23. inner ring; 24. gas seal arc; 25. labyrinth seal tooth; 51. guide vane casing; 52. intermediate casing; 53. bolts; 71. blade diffuser; 72. outer wall; 73. inner wall; 81. outlet guide vane; 82. side wall. DETAILED DESCRIPTION

[0032] Reference Figures 1-11 A mixed flow compressor comprises a multi-stage axial flow compressor A and a single-stage centrifugal compressor B, wherein the multi-stage axial flow compressor and the single-stage centrifugal compressor share a same rotor;

[0033] Air enters the axial flow section of the compressor through the intake chamber, is compressed and then enters the centrifugal section, where it is further compressed and then supplied to the combustion chamber;

[0034] The mixed flow compressor adopts a combination of axial flow and centrifugal flow, which can combine the characteristics of smooth flow path, high efficiency, and adaptability to large inlet flow of the axial flow stage and the characteristics of adaptability to small flow, wide operating range, few parts and high reliability of the centrifugal stage;

[0035] The multi-stage axial flow compressor includes an air inlet chamber 1, an axial flow compressor casing 2 and a compressor rotor 3. A plurality of sets of axial flow compressor rotor blades 5 are fixed on the outer ring surface of the compressor rotor. A plurality of sets of compressor guide vane assemblies 6 are fixed in the axial flow compressor casing. The axial flow compressor rotor blades and the compressor guide vane assemblies are arranged at intervals.

[0036] The multi-stage axial flow compressor is first provided with a row of inlet guide vanes along the air flow direction, and then alternately provided with a row of moving blades and a row of stationary blades, and all blades are evenly arranged along the circumferential direction at a certain installation angle;

[0037] The multi-stage axial flow compressor has a meridian flow channel structure composed of the end walls of nine stages of moving and static blades. The meridian flow channel is formed in a form similar to equal outer diameter. The upper end wall is horizontal, and the upper and lower end walls of the blades are designed to form a certain angle with the center line. The upper and lower meridian flow channels form a certain reasonable angle with the center line, ensuring the aerodynamic efficiency of the nine-stage high-pressure compressor at 13,300 revolutions per minute.

[0038] A multi-stage axial flow compressor first has a row of inlet guide vanes along the air flow direction, and then a row of moving blades and a row of stationary blades are arranged alternately. First, a row of inlet guide vanes are used to guide the air, and then the air is accelerated by a row of moving blades. After acceleration, the air is decelerated in the row of stationary blades, converting the kinetic energy in the rotor into static pressure energy. This process is repeated in multiple stages of blades until the total pressure ratio reaches the requirement.

[0039] The multi-stage axial flow compressor inlet guide vanes adopt a variable angle design. The inlet guide vanes can stabilize the compressor and reduce the degree of distortion of the compressor. Through the variable angle design, the airflow passing through the inlet guide vanes generates pre-swirl, which reduces the angle of attack when entering the rotor. The angle of the airflow entering the first stage of the compressor is adjusted as the speed changes, thereby improving off-design performance, suppressing airflow separation, and improving compressor operating conditions.

[0040] The first and second stages of the compressor stator blades also adopt a variable angle design, which can increase the stable operating margin of the compressor, ensure that the airflow passes through the compressor at an approximately constant axial speed, prevent air flow loss and compressor surge, improve the low-load performance of the compressor, better match the performance of various components of the gas turbine, control the turbine exhaust temperature, and improve the efficiency of the combined cycle.

[0041] Each stage of the multi-stage axial flow compressor has a plurality of rotor discs and axial flow compressor blades evenly arranged along the circumferential direction, and the two are connected by a blade root groove, and the blade root shape can be dovetail, fork or tooth;

[0042] The single-stage centrifugal compressor includes a centrifugal impeller 11, an impeller cover 12, a centrifugal compressor casing 13 and a centrifugal wheel 10;

[0043] Multiple sets of rotor discs 8 are fixed in the compressor rotor, and the centrifugal discs 10 of the single-stage centrifugal compressor are connected to the rotor discs of the last stage of the multi-stage axial flow compressor via flanges;

[0044] The centrifugal compressor casing is connected to the axial flow compressor casing via a flange.

[0045] The centrifugal compressor is characterized by its small size and high single-stage compression ratio. It combines an axial-flow compressor and a centrifugal compressor. Through a common rotor shaft, the intake air is first pressurized and deflected in the axial-flow compressor, and then enters the centrifugal compressor. Under low-flow conditions, a large deflection of the intake angle can be achieved, thereby achieving high flow and high compression ratio in a small space.

[0046] The single-stage centrifugal compressor includes a centrifugal impeller 11, an impeller cover 12, a centrifugal compressor casing 13 and a centrifugal wheel disc 10. The centrifugal impeller is fixed on the centrifugal wheel disc. The centrifugal impeller 11 and the centrifugal wheel disc 10 are forged as a whole. The impeller cover is clearance-matched with the centrifugal impeller. The impeller cover is fixed to the centrifugal compressor casing by bolts. The mating surface of the impeller cover is provided with a labyrinth sealing tooth structure.

[0047] The compressor guide vane assembly includes an outer ring 21, compressor vanes 22, an inner ring 23, and an air seal arc 24. The outer ring is provided with dovetail grooves, and the number of dovetail grooves on each stage of the outer ring is equal to the number of compressor vanes. The compressor vanes are fixed to the dovetail grooves. The air seal arc is connected to the inner ring. The inner ring and the compressor vanes are fixed with rivets. The outer ring is circumferentially inserted into a matching groove in the compressor casing.

[0048] The design of grooves on the casing and the installation of the outer ring in the grooves greatly reduce the installation burden. At the same time, from the processing technology point of view, the compressor stators of each stage are of the same size and the compressor stator blades are of the same length, making it more convenient for actual production and manufacturing;

[0049] The compressor rotor is in the form of a drum, and is connected to the first-stage / last-stage rotor disc via a flange, and is welded to the intermediate-stage disc via an electron beam.

[0050] The compressor casing includes a guide vane casing 51 and an intermediate casing 52 , and the vane casing 51 and the intermediate casing are connected by bolts 53 .

[0051] The axial flow compressor rotor blades are clearance-matched with the axial flow compressor casing, and the clearance d is 0.3-0.5 mm.

[0052] The compressor rotor is provided with a labyrinth seal tooth structure. The labyrinth seal teeth 25 and the air seal arc 24 form a seal together to prevent air leakage between compressor stages and ensure aerodynamic efficiency. At the same time, the multi-stage labyrinth seal tooth structure can enhance the sealing effect.

[0053] The compressor rotor is equipped with a labyrinth seal tooth structure, which can effectively isolate the cylinder temperature and prevent hot gas from entering the cylinder, thereby achieving the effect of sealing the cylinder, improving the sealing performance of the high-pressure compressor wheel, and thus effectively increasing the life of the turbine cylinder, ensuring the safe and efficient operation of the gas turbine.

[0054] The axial flow compressor rotor blades and compressor stator blades are both titanium alloy blades.

[0055] The diffuser section of the single-stage centrifugal compressor comprises an inner wall 73 and an outer wall 72, with a vaned diffuser 71 positioned between them. Air exiting the impeller has a high velocity, and therefore significant kinetic energy. This kinetic energy accounts for approximately 25%-50% of the impeller's machining volume. The diffuser section is equipped with a vaned diffuser to reduce air velocity and increase static pressure. The outlet guide vane assembly is equipped with guide vanes to ensure radial outflow.

[0056] An outlet guide vane assembly is provided above the blade diffuser. The outlet guide vanes 81 are welded to the end walls 82 on both sides and fixed to the diffuser end cover by bolts.

[0057] The utility model proposes a mixed flow multi-stage compressor for gas turbines, which can achieve high pressure ratio and high efficiency at low flow rate. The axial flow compressor and the centrifugal compressor share a rotor, and the overall structure is simple, easy to process, and suitable for popularization and use.

[0058] A mixed flow method for a mixed flow compressor, the method comprising the following steps:

[0059] (1) The air flow is first guided by a row of inlet guide vanes, then accelerated by a row of moving blades. After acceleration, it is decelerated in the stator blade channel, converting the kinetic energy in the rotor into static pressure energy. Then, the air flow is alternately arranged in rows of moving blades and stator blades. This process is repeated in multiple stages of blades until the total pressure ratio reaches the required level.

[0060] (2) After the air is drawn out from the axial compressor, it enters the centrifugal compressor, where it is further compressed. The air is discharged after passing through the diffuser blades in the diffuser section, which reduces the air velocity and increases the air static pressure. The outlet guide vane assembly is provided with guide vanes for the air to flow out in the radial direction. Since the air has a very high air velocity after exiting the working impeller, it also has a large amount of kinetic energy. This part of kinetic energy accounts for about 25%-50% of the impeller processing volume. The outlet guide vane assembly is provided with guide vanes for the air to flow out in the radial direction.

Claims

1. A mixed flow compressor, characterized by: It comprises a multi-stage axial flow compressor and a single-stage centrifugal compressor, wherein the multi-stage axial flow compressor and the single-stage centrifugal compressor share the same rotor; The multi-stage axial flow compressor includes an air inlet chamber, an axial flow compressor casing, and a compressor rotor. Multiple sets of axial flow compressor rotor blades are fixed on the outer annular surface of the compressor rotor. Multiple sets of compressor guide vane assemblies are fixed in the axial flow compressor casing. The axial flow compressor rotor blades and the compressor guide vane assemblies are arranged at intervals. The single-stage centrifugal compressor comprises a centrifugal impeller, an impeller cover, a centrifugal compressor casing and a centrifugal wheel; Multiple sets of rotor discs are fixed in the compressor rotor, and the centrifugal discs of the single-stage centrifugal compressor are connected to the rotor discs of the last stage of the multi-stage axial flow compressor via flanges; The centrifugal compressor casing is connected to the axial flow compressor casing via a flange.

2. A mixed flow compressor according to claim 1, characterized in that: The single-stage centrifugal compressor includes a centrifugal impeller, an impeller cover, a centrifugal compressor casing and a centrifugal wheel disc. The centrifugal impeller is fixed on the centrifugal wheel disc. The impeller cover is clearance-matched with the centrifugal impeller. The impeller cover is fixed to the centrifugal compressor casing by bolts. The mating surface of the impeller cover is provided with a labyrinth sealing tooth structure.

3. The mixed flow compressor according to claim 1, characterized in that: The compressor guide vane assembly includes an outer ring, compressor stator blades, an inner ring and an air seal arc; the outer ring is provided with dovetail grooves, the number of dovetail grooves on each stage of the outer ring is equal to the number of compressor stator blades, and the compressor stator blades are fixed to the dovetail grooves; the air seal arc is connected to the inner ring; the inner ring and the compressor stator blades are fixed with rivets, and the outer ring is circumferentially inserted into a matching groove opened in the compressor casing.

4. The mixed flow compressor according to claim 1, characterized in that: The compressor rotor is in the form of a drum, and is connected to the first-stage / last-stage rotor disc via a flange, and is welded to the intermediate-stage disc via an electron beam.

5. The mixed flow compressor according to claim 1, characterized in that: The compressor casing comprises a guide vane casing and an intermediate casing, and the vane casing and the intermediate casing are connected by bolts.

6. The mixed flow compressor according to claim 1, characterized in that: The axial flow compressor rotor blades are clearance-matched with the axial flow compressor casing, and the clearance d is 0.3-0.5 mm.

7. The mixed flow compressor according to claim 1, characterized in that: The compressor rotor is provided with a labyrinth seal tooth structure, and the labyrinth seal teeth form a seal together with the gas seal arc.

8. The mixed flow compressor according to claim 3, characterized in that: The axial flow compressor rotor blades and compressor stator blades are both titanium alloy blades.

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