A supercritical carbon dioxide centrifugal turbine structure suitable for 600℃ intake air

Abstract

A supercritical carbon dioxide centrifugal turbine structure adapted to 600°C intake belongs to the field of turbine technology. The present invention is to solve the problem of difficult sealing of a 25MPa-600°C supercritical carbon dioxide turbine. It includes a low-pressure centrifugal turbine, a gearbox and a high-pressure centrifugal turbine; the gearbox is provided with a rotor with cantilevered ends, one end of the rotor passes through the low-pressure sealing casing and the low-pressure heat-insulating casing of the low-pressure centrifugal turbine and extends into the low-pressure volute, and is connected to the low-pressure centrifugal impeller, the low-pressure sealing casing is connected to the rotor through a dry gas seal, and a low-temperature carbon dioxide gas source is connected to the inside of the low-pressure sealing casing through a pipeline, and the other end of the rotor has the same matching relationship with the high-pressure centrifugal turbine as the low-pressure end, and low-temperature carbon dioxide gas is introduced from the outside to cool the dry gas seal, thereby solving the problem of difficult sealing of a 25MPa-600°C supercritical carbon dioxide turbine with high intake parameters.

Description

Technical Field

[0001] The invention belongs to the technical field of turbines, and in particular relates to a supercritical carbon dioxide centripetal turbine structure suitable for 600°C intake air. Background Art

[0002] The traditional power generation system uses the steam Rankine cycle, and the efficiency of the 600℃ ultra-supercritical coal-fired single-reheat unit is 44.5%. However, the realization of the higher-efficiency 700℃ ultra-supercritical steam cycle faces problems such as the difficulty in developing nickel-based high-temperature alloy materials, the difficulty in arranging high-temperature boilers and turbines, and excessively high investment costs, and is currently difficult to achieve.

[0003] The supercritical carbon dioxide cycle power generation system has the advantages of cleanliness, high efficiency, compact structure, and flexible start and stop. At a temperature of 600°C, it can achieve the efficiency of the steam Rankine cycle at 700°C. It has good technical inheritance and can be implemented based on existing materials.

[0004] The turbine is the core component of the supercritical carbon dioxide cycle power generation unit and has a decisive influence on the cycle efficiency. High-temperature and high-pressure carbon dioxide enters the turbine, drives the turbine to do work, and drives the generator to generate electricity. In order to pursue high efficiency equivalent to 700℃ ultra-supercritical steam power generation, it is necessary to increase the temperature and pressure of the system's thermal cycle. The supercritical carbon dioxide thermal cycle pressure is required to reach 25MPa and the temperature to reach 600℃. Due to the high internal pressure and temperature of the turbine, traditional seals such as comb teeth and carbon rings can no longer meet the sealing requirements. Summary of the invention

[0005] The purpose of the present invention is to provide a supercritical carbon dioxide centripetal turbine structure adapted to 600°C intake air, so as to solve the problem of difficult sealing of 25MPa-600°C supercritical carbon dioxide turbine. The technical solution adopted by the present invention is as follows:

[0006] A supercritical carbon dioxide centrifugal turbine structure adapted to 600°C intake air, comprising a low-pressure centrifugal turbine, a gear box and a high-pressure centrifugal turbine;

[0007] The gearbox includes a rotor, a bearing and a gearbox housing. The rotor is rotatably arranged on the gearbox housing through the bearing. Both ends of the gearbox housing are respectively provided with oil retaining rings matching with the rotor.

[0008] The low-pressure centrifugal turbine comprises a low-pressure volute, a low-pressure centrifugal impeller, a low-pressure heat-insulating casing and a low-pressure sealed casing; the low-pressure volute, the low-pressure heat-insulating casing and the low-pressure sealed casing are coaxially flange-connected in sequence, the other end of the low-pressure sealed casing is connected to the gear box housing, one end of the rotor passes through the low-pressure sealed casing and the low-pressure heat-insulating casing in sequence, and extends into the low-pressure volute, and cooperates with the stop of the low-pressure centrifugal impeller, one end of the low-pressure centrifugal impeller is provided with a low-pressure impeller sleeve, the outer periphery of the rotor and the low-pressure impeller sleeve The inner circumference of the sleeve is matched by a spline structure, a dry gas seal is arranged in the low-pressure sealed casing, the low-pressure sealed casing is connected to the rotor through the dry gas seal, the low-temperature carbon dioxide gas source is connected to the inside of the low-pressure sealed casing through a pipeline, and a low-pressure end sealing tooth is arranged on the inner hole of the low-pressure heat-insulating casing, and the low-pressure end sealing tooth is matched with the outer peripheral clearance of the low-pressure impeller sleeve, and a plurality of low-pressure guide vanes are arranged on the circumference of the low-pressure heat-insulating casing, and the plurality of low-pressure guide vanes are located on the air inlet channel on the outer periphery of the low-pressure centripetal impeller;

[0009] The high-pressure centrifugal turbine comprises a high-pressure volute, a high-pressure centrifugal impeller, a high-pressure heat-insulating casing and a high-pressure sealed casing; the high-pressure volute, the high-pressure heat-insulating casing and the high-pressure sealed casing are coaxially flange-connected in sequence, the other end of the high-pressure sealed casing is connected to the gear box housing, the other end of the rotor passes through the high-pressure sealed casing and the high-pressure heat-insulating casing in sequence, and extends into the high-pressure volute, and cooperates with the stopper of the high-pressure centrifugal impeller, one end of the high-pressure centrifugal impeller is provided with a high-pressure impeller sleeve, the outer periphery of the rotor and the inner periphery of the high-pressure impeller sleeve are matched through a spline structure, a dry gas seal is provided in the high-pressure sealed casing, the high-pressure sealed casing is connected to the rotor through the dry gas seal, a low-temperature carbon dioxide gas source is connected to the inside of the high-pressure sealed casing through a pipeline, the inner hole of the high-pressure heat-insulating casing is provided with a high-pressure end sealing tooth, the high-pressure end sealing tooth is matched with the outer peripheral clearance of the high-pressure impeller sleeve, a plurality of high-pressure guide vanes are arranged on the circumference of the high-pressure heat-insulating casing, and the plurality of high-pressure guide vanes are located on the air inlet channel on the periphery of the high-pressure centrifugal impeller.

[0010] Furthermore, a plurality of low-pressure guide blades are integrally formed with the low-pressure insulation casing, the top ends of the plurality of low-pressure guide blades are connected via a first annular belt, a first annular groove is provided on the low-pressure volute, and the first annular belt matches the first annular groove; a plurality of high-pressure guide blades are integrally formed with the high-pressure insulation casing, the top ends of the plurality of high-pressure guide blades are connected via a second annular belt, a second annular groove is provided on the high-pressure volute, and the second annular belt matches the second annular groove.

[0011] Furthermore, a first abradable coating is provided on the inner cavity wall of the low-pressure volute, and the first abradable coating is provided in the fitting gap area between the low-pressure volute and the low-pressure centrifugal impeller. A second abradable coating is provided on the inner cavity wall of the high-pressure volute, and the second abradable coating is provided in the fitting gap area between the high-pressure volute and the high-pressure centrifugal impeller.

[0012] Furthermore, a low-pressure bracket is provided below the low-pressure volute, and a high-pressure bracket is provided below the high-pressure volute.

[0013] Furthermore, a heat insulating pad is provided between the low-pressure volute and the low-pressure bracket, and a heat insulating pad is provided between the high-pressure volute and the high-pressure bracket.

[0014] Furthermore, the circumference of the low-pressure volute is matched with the low-pressure bracket through the first guide key, and the circumference of the high-pressure volute is matched with the high-pressure bracket through the second guide key.

[0015] Furthermore, the high-pressure volute and the high-pressure heat-insulating casing are sealed by a C-type sealing ring, and the low-pressure volute and the low-pressure heat-insulating casing are sealed by a C-type sealing ring.

[0016] Furthermore, the bearing is a tilting pad bearing.

[0017] Furthermore, the rotation speed of the rotor is 32000 r / min.

[0018] Furthermore, the high-pressure sealed casing is a casing made of GH4169 material, the high-pressure heat-insulating casing is a casing made of GH4169 material, the high-pressure radial impeller is an impeller made of GH4169 material, the high-pressure volute is a volute made of GH4169 material, the low-pressure sealed casing is a casing made of GH4169 material, the low-pressure heat-insulating casing is a casing made of GH4169 material, the low-pressure radial impeller is an impeller made of GH4169 material, and the low-pressure volute is a volute made of GH4169 material.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. The present invention adopts a structural layout scheme in which high-pressure and low-pressure two-stage centrifugal turbines are connected in series and arranged symmetrically back to back on both sides of the reduction gearbox. It integrates the advantages of good turbine sealing, normal operation of the seal at a high temperature of 600°C, small gap between the impeller and the volute, good stability of the guide vane, and the center alignment of the volute and the rotor at both ends under heating, etc., and provides a structural solution for the design of high-parameter (25MPa / 600°C) small-capacity (MW-level) supercritical CO2 turbines.

[0021] 2. The high and low pressure ends are sealed by dry gas sealing. Low temperature CO2 gas is introduced from the outside to cool the dry gas seal, which solves the problem of difficult sealing of supercritical carbon dioxide turbine with high intake parameters of 25MPa-600℃.

[0022] 3. The matching areas of the volute and the radial impeller at the high and low pressure ends are both provided with abradable sealing coatings. When the radial impeller rotates, the excess coating is worn away, realizing a small gap design between the radial impeller and the volute, ensuring high efficiency of the turbine while taking into account the safety of turbine operation.

[0023] 4. The guide vanes at the high and low pressure ends are integrated with the heat-insulating casing on the same side. An annular belt is welded on the top of the guide vane. At the same time, an annular groove structure is set on the corresponding volute to cooperate with the installation of the annular belt to ensure that the guide vanes work stably and efficiently under the conditions of heat, pressure and deformation of the volute at the high and low pressure ends.

[0024] 5. Insulation pads are installed between the volutes and brackets at the high and low pressure ends for heat insulation, and the guide keys can ensure that the volutes and rotors at both ends are aligned in the heated state. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the structure of the present invention;

[0026] Figure 2 It is a schematic diagram of the structure of a low-pressure centripetal turbine;

[0027] Figure 3 It is a schematic diagram of the coordination between the low-pressure volute and the low-pressure bracket;

[0028] Figure 4 It is an exploded schematic diagram of the low-pressure heat-insulated casing and the first annular shroud;

[0029] Figure 5 yes Figure 2 A magnified image of point A;

[0030] Figure 6 yes Figure 2 A magnified view of point B;

[0031] Figure 7 It is a schematic diagram of the structure of the gearbox;

[0032] Figure 8 It is a schematic diagram of the structure of a high-pressure centripetal turbine;

[0033] Fig. 9 It is a schematic diagram of the coordination between the high-pressure volute and the high-pressure bracket;

[0034] Fig.10 It is an exploded schematic diagram of the high-pressure heat-insulated casing and the second annular shroud;

[0035] Fig.11 yes Figure 8 Enlarged view of point C;

[0036] Fig.12 yes Figure 8 The enlarged view of point D;

[0037] In the figure: 1- low-pressure centrifugal turbine, 11- low-pressure volute, 111- first abradable coating, 12- low-pressure centrifugal impeller, 13- low-pressure heat-insulating casing, 131- low-pressure guide vane, 132- first annular shroud, 133- low-pressure end sealing tooth, 14- dry gas seal, 15- low-pressure sealing casing, 16- first guide key, 17- low-pressure bracket, 18- low-pressure fastening bolt, 19- heat-insulating pad, 2- gear box, 21 -gearbox housing, 22-oil retaining ring, 23-rotor, 24-bearing, 3-high-pressure centrifugal turbine, 31-high-pressure volute, 311-second abradable coating, 32-high-pressure centrifugal impeller, 33-high-pressure heat-insulating casing, 331-high-pressure guide vane, 332-second annular belt, 333-high-pressure end sealing tooth, 34-high-pressure fastening bolt, 35-high-pressure sealing casing, 36-second guide key, 37-high-pressure bracket. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is described below by the specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0039] The connection mentioned in the present invention is divided into fixed connection and detachable connection. The fixed connection is a non-detachable connection including but not limited to conventional fixed connection methods such as folding connection, rivet connection, bonding connection and welding connection. The detachable connection includes but not limited to conventional detachable methods such as bolt connection, snap connection, pin connection and hinge connection. When the specific connection method is not clearly defined, it is assumed that at least one connection method can be found in the existing connection methods to achieve the function, and those skilled in the art can choose according to their needs. For example: welding connection is selected for fixed connection, and bolt connection is selected for detachable connection.

[0040] The present invention will be further described in detail below in conjunction with the accompanying drawings. The following embodiments are provided to explain the present invention, but the present invention is not limited to the following embodiments.

[0041] Example: Figure 1-12 As shown, a supercritical carbon dioxide centrifugal turbine structure adapted to 600°C intake air comprises a low-pressure centrifugal turbine 1, a gear box 2 and a high-pressure centrifugal turbine 3;

[0042] The gearbox 2 includes a rotor 23, a bearing 24 and a gearbox housing 31. The rotor 23 is rotatably arranged on the gearbox housing 31 through the bearing 24. Both ends of the gearbox housing 31 are respectively provided with oil retaining rings 22 that match the rotor 23.

[0043] The low-pressure centrifugal turbine 1 comprises a low-pressure volute 11, a low-pressure centrifugal impeller 12, a low-pressure heat-insulating casing 13 and a low-pressure sealed casing 15; the low-pressure volute 11, the low-pressure heat-insulating casing 13 and the low-pressure sealed casing 15 are coaxially flange-connected in sequence, the other end of the low-pressure sealed casing 15 is connected to the gear box housing 31, one end of the rotor 23 passes through the low-pressure sealed casing 15 and the low-pressure heat-insulating casing 13 in sequence, and extends into the low-pressure volute 11, and cooperates with the stopper of the low-pressure centrifugal impeller 12, one end of the low-pressure centrifugal impeller 12 is provided with a low-pressure impeller sleeve, the outer periphery of the rotor 23 and the low-pressure impeller The inner circumference of the pipe sleeve is matched by a spline structure, a dry gas seal 14 is provided in the low-pressure sealed casing 15, the low-pressure sealed casing 15 is connected to the rotor 23 through the dry gas seal 14, the low-temperature carbon dioxide gas source is connected to the inside of the low-pressure sealed casing 15 through a pipeline, and the inner hole of the low-pressure heat-insulating casing 13 is provided with a low-pressure end sealing tooth 133, the low-pressure end sealing tooth 133 is matched with the outer peripheral clearance of the low-pressure impeller pipe sleeve, and a plurality of low-pressure guide blades 131 are provided on the circumference of the low-pressure heat-insulating casing 13, and the plurality of low-pressure guide blades 131 are located on the air inlet channel on the outer periphery of the low-pressure centripetal impeller 12;

[0044] The high-pressure centrifugal turbine 3 includes a high-pressure volute 31, a high-pressure centrifugal impeller 32, a high-pressure heat-insulating casing and a high-pressure sealing casing 35; the high-pressure volute 31, the high-pressure heat-insulating casing and the high-pressure sealing casing 35 are coaxially flange-connected in sequence, and the other end of the high-pressure sealing casing 35 is connected to the gear box housing 31. The other end of the rotor 23 passes through the high-pressure sealing casing 35 and the high-pressure heat-insulating casing in sequence, and extends into the high-pressure volute 31, and cooperates with the stopper of the high-pressure centrifugal impeller 32. One end of the high-pressure centrifugal impeller 32 is provided with a high-pressure impeller sleeve, and the outer periphery of the rotor 23 and the high-pressure impeller The inner circumference of the pipe sleeve is matched by a spline structure, and a dry gas seal 14 is provided in the high-pressure sealed casing 35. The high-pressure sealed casing 35 is connected to the rotor 23 through the dry gas seal 14. The low-temperature carbon dioxide gas source is connected to the inside of the high-pressure sealed casing 35 through a pipeline. The inner hole of the high-pressure heat-insulating casing is provided with a high-pressure end sealing tooth 333, and the high-pressure end sealing tooth 333 is matched with the outer peripheral clearance of the high-pressure impeller pipe sleeve. A plurality of high-pressure guide vanes 331 are arranged on the circumference of the high-pressure heat-insulating casing, and the plurality of high-pressure guide vanes 331 are located on the air intake channel on the periphery of the high-pressure centripetal impeller 32.

[0045] The high and low pressure ends are sealed by dry gas sealing, and low temperature CO2 gas is introduced from the outside to cool the dry gas seal, which solves the problem of difficult sealing of supercritical carbon dioxide turbine with high intake parameters of 25MPa-600℃.

[0046] A number of low-pressure guide blades 131 are respectively integrally formed with the low-pressure heat-insulating casing 13, and the top ends of the number of low-pressure guide blades 131 are connected through a first annular band 132. A first annular groove is provided on the low-pressure volute 11, and the first annular band 132 matches the first annular groove. A number of high-pressure guide blades 331 are respectively integrally formed with the high-pressure heat-insulating casing, and the top ends of the number of high-pressure guide blades 331 are connected through a second annular band 332. A second annular groove is provided on the high-pressure volute 31, and the second annular band 332 matches the second annular groove.

[0047] The guide vanes at the high and low pressure ends are integrally processed and manufactured with the heat-insulating casing on the same side. An annular belt is welded on the top of the guide vane. At the same time, an annular groove structure is provided on the corresponding volute to cooperate with the installation of the annular belt to ensure that the guide vanes at the high and low pressure ends of the volute work stably and efficiently under the conditions of heat, pressure and deformation.

[0048] A first abradable coating 111 is provided on the inner cavity wall of the low-pressure volute 11, and the first abradable coating 111 is provided in the fitting gap area between the low-pressure volute 11 and the low-pressure centrifugal impeller 12. A second abradable coating 311 is provided on the inner cavity wall of the high-pressure volute 31, and the second abradable coating 311 is provided in the fitting gap area between the high-pressure volute 31 and the high-pressure centrifugal impeller 32.

[0049] The volute and the radial impeller mating area at the high and low pressure ends are provided with abradable sealing coatings. When the radial impeller rotates, the excess coating is worn away, realizing a small gap design between the radial impeller and the volute, ensuring high efficiency of the turbine while taking into account the safety of turbine operation.

[0050] A low-pressure support 17 is provided below the low-pressure volute 11 , and a high-pressure support 37 is provided below the high-pressure volute 31 .

[0051] A heat insulating pad 19 is provided between the low-pressure volute 11 and the low-pressure bracket 17 , and a heat insulating pad 19 is provided between the high-pressure volute 31 and the high-pressure bracket 37 .

[0052] The circumference of the low-pressure volute 11 is matched by the first guide key 16 and the low-pressure bracket 17 , and the circumference of the high-pressure volute 31 is matched by the second guide key 36 and the high-pressure bracket 37 .

[0053] Insulation pads are installed between the volutes and brackets at the high and low pressure ends for heat insulation, and guide keys can ensure that the volutes and rotors at both ends are aligned in the center when heated.

[0054] The high-pressure volute 31 is sealed with the high-pressure heat-insulating casing by a C-shaped sealing ring, and the low-pressure volute 11 is sealed with the low-pressure heat-insulating casing 13 by a C-shaped sealing ring.

[0055] The bearing 24 is a tilting pad bearing 24 .

[0056] The rotation speed of the rotor 23 is 32000 r / min.

[0057] The high-pressure sealing casing 35 is made of GH4169 material, the high-pressure heat-insulating casing is made of GH4169 material, the high-pressure radial impeller 32 is made of GH4169 material, the high-pressure volute 31 is made of GH4169 material, the low-pressure sealing casing 15 is made of GH4169 material, the low-pressure heat-insulating casing 13 is made of GH4169 material, the low-pressure radial impeller 12 is made of GH4169 material, and the low-pressure volute 11 is made of GH4169 material. High-temperature resistant alloy materials are selected to meet the use requirements of 600℃ high temperature.

[0058] The low-pressure centrifugal turbine 1 and the high-pressure centrifugal turbine 3 utilize gas with a certain pressure to perform adiabatic expansion inside the turbine to perform external work and consume the internal energy of the gas. The turbine in this application is a centrifugal turbine. The gas flows into the turbine along the radial direction in a plane perpendicular to the rotation axis, passes through the guide vanes and the rotating impeller in sequence, and then flows out from the axial direction.

[0059] In the present application, the carbon dioxide gas flow flows into the turbine from the high-pressure volute inlet, flows through the high-pressure guide vanes and the high-pressure impeller, and then flows out from the high-pressure turbine outlet. The carbon dioxide gas flowing out of the high-pressure volute passes through the intermediate pipe and enters the low-pressure volute inlet. The structure of the low-pressure turbine is similar to that of the high-pressure turbine. After the gas flow enters the low-pressure volute inlet (not shown in the accompanying drawings), it flows through the low-pressure guide vanes and the low-pressure impeller in sequence and then flows out from the low-pressure turbine outlet.

[0060] The rotor 23 is provided with a high-speed gear, which is meshed with a driving wheel, and the driving wheel is sleeved on the output shaft of the driving motor. The driving motor drives the low-pressure radial impeller 12 and the high-pressure radial impeller 32 to rotate in the corresponding volutes through gear transmission. This part is not shown in the accompanying drawings, but this part and the other undescribed parts are all prior art and can be selected from the published literature.

[0061] The above embodiments are merely illustrative of the present invention and do not limit its protection scope. Those skilled in the art may also make partial changes thereto, and as long as they do not exceed the spirit of the present invention, they are all within the protection scope of the present invention.

Claims

1. A supercritical carbon dioxide centrifugal turbine structure suitable for 600℃ intake air, Features: The invention comprises a low-pressure centrifugal turbine (1), a gear box 2 and a high-pressure centrifugal turbine (3); the gear box 2 comprises a rotor (23), a bearing (24) and a gear box housing (31); the rotor (23) is rotatably arranged on the gear box housing (31) via the bearing (24); and oil retaining rings (22) matching with the rotor (23) are respectively arranged at both ends of the gear box housing (31); A low-pressure centrifugal turbine (1) comprises a low-pressure volute (11), a low-pressure centrifugal impeller (12), a low-pressure heat-insulating casing (13) and a low-pressure sealing casing (15); the low-pressure volute (11), the low-pressure heat-insulating casing (13) and the low-pressure sealing casing (15) are coaxially flange-connected in sequence, the other end of the low-pressure sealing casing (15) is connected to a gear box housing (31), one end of a rotor (23) passes through the low-pressure sealing casing (15) and the low-pressure heat-insulating casing (13) in sequence, and extends into the low-pressure volute (11), and cooperates with the stopper of the low-pressure centrifugal impeller (12), one end of the low-pressure centrifugal impeller (12) is provided with a low-pressure impeller sleeve, the outer periphery of the rotor (23) and the The inner circumference of the low-pressure impeller sleeve is matched by a spline structure, a dry gas seal (14) is provided in the low-pressure sealing casing (15), the low-pressure sealing casing (15) is connected to the rotor (23) through the dry gas seal (14), the low-temperature carbon dioxide gas source is connected to the inside of the low-pressure sealing casing (15) through a pipeline, the inner hole of the low-pressure heat-insulating casing (13) is provided with a low-pressure end sealing tooth (133), the low-pressure end sealing tooth (133) is matched with the outer peripheral clearance of the low-pressure impeller sleeve, and a plurality of low-pressure guide blades (131) are provided on the circumference of the low-pressure heat-insulating casing (13), and the plurality of low-pressure guide blades (131) are located on the air inlet channel on the outer periphery of the low-pressure centripetal impeller (12); The high-pressure centrifugal turbine (3) comprises a high-pressure volute (31), a high-pressure centrifugal impeller (32), a high-pressure heat-insulating casing and a high-pressure sealing casing (35); the high-pressure volute (31), the high-pressure heat-insulating casing and the high-pressure sealing casing (35) are coaxially flange-connected in sequence, the other end of the high-pressure sealing casing (35) is connected to the gear box housing (31), the other end of the rotor (23) passes through the high-pressure sealing casing (35) and the high-pressure heat-insulating casing in sequence, and extends into the high-pressure volute (31), and cooperates with the stopper of the high-pressure centrifugal impeller (32), one end of the high-pressure centrifugal impeller (32) is provided with a high-pressure impeller sleeve, the outer periphery of the rotor (23) and the high-pressure The inner circumference of the impeller sleeve is matched by a spline structure, a dry gas seal (14) is provided in the high-pressure sealing casing (35), the high-pressure sealing casing (35) is connected to the rotor (23) through the dry gas seal (14), a low-temperature carbon dioxide gas source is connected to the inside of the high-pressure sealing casing (35) through a pipeline, a high-pressure end sealing tooth (333) is provided in the inner hole of the high-pressure heat-insulating casing, the high-pressure end sealing tooth (333) is matched with the outer circumferential clearance of the high-pressure impeller sleeve, a plurality of high-pressure guide vanes (331) are provided on the circumference of the high-pressure heat-insulating casing, and the plurality of high-pressure guide vanes (331) are located on the air inlet channel on the outer circumference of the high-pressure centripetal impeller (32); A low-pressure support (17) is provided below the low-pressure volute (11), and a high-pressure support (37) is provided below the high-pressure volute (31); The high-pressure volute (31) and the high-pressure heat-insulating casing are sealed by a C-shaped sealing ring, and the low-pressure volute (11) and the low-pressure heat-insulating casing (13) are sealed by a C-shaped sealing ring.

2. A supercritical carbon dioxide centrifugal turbine structure adapted to 600°C intake air according to claim 1, Features: A plurality of low-pressure guide blades (131) are respectively integrally formed with the low-pressure heat-insulating casing (13), the top ends of the plurality of low-pressure guide blades (131) are connected via a first annular shroud (132), a first annular groove is provided on the low-pressure volute (11), and the first annular shroud (132) matches the first annular groove; a plurality of high-pressure guide blades (331) are respectively integrally formed with the high-pressure heat-insulating casing, the top ends of the plurality of high-pressure guide blades (331) are connected via a second annular shroud (332), a second annular groove is provided on the high-pressure volute (31), and the second annular shroud (332) matches the second annular groove.

3. A supercritical carbon dioxide centrifugal turbine structure adapted to 600°C intake air according to claim 1, Features: A first abradable coating (111) is provided on the inner cavity wall of the low-pressure volute (11), and the first abradable coating (111) is provided in the matching gap area between the low-pressure volute (11) and the low-pressure centrifugal impeller (12); a second abradable coating (311) is provided on the inner cavity wall of the high-pressure volute (31), and the second abradable coating (311) is provided in the matching gap area between the high-pressure volute (31) and the high-pressure centrifugal impeller (32).

4. A supercritical carbon dioxide centrifugal turbine structure adapted to 600°C intake air according to claim 1, Features: A heat insulating pad (19) is provided between the low-pressure volute (11) and the low-pressure support (17), and a heat insulating pad (19) is provided between the high-pressure volute (31) and the high-pressure support (37).

5. A supercritical carbon dioxide centrifugal turbine structure adapted to 600°C intake air according to claim 4, Features: The circumference of the low-pressure volute (11) is matched with the first guide key (16) and the low-pressure bracket (17), and the circumference of the high-pressure volute (31) is matched with the second guide key (36) and the high-pressure bracket (37).

6. A supercritical carbon dioxide centrifugal turbine structure adapted to 600°C intake air according to claim 1, Features: The bearing (24) is a tilting pad bearing (24).

7. A supercritical carbon dioxide centrifugal turbine structure adapted to 600°C intake air according to claim 1, Features: The rotation speed of the rotor (23) is 32000 r / min.

8. A supercritical carbon dioxide centrifugal turbine structure adapted to 600°C intake air according to any one of claims 1 to 7, Features: The high-pressure sealing casing (35) is a casing made of GH4169 material, the high-pressure heat-insulating casing is a casing made of GH4169 material, the high-pressure centrifugal impeller (32) is a impeller made of GH4169 material, the high-pressure volute (31) is a volute made of GH4169 material, the low-pressure sealing casing (15) is a casing made of GH4169 material, the low-pressure heat-insulating casing (13) is a casing made of GH4169 material, the low-pressure centrifugal impeller (12) is a impeller made of GH4169 material, and the low-pressure volute (11) is a volute made of GH4169 material.

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