Coupling structure of high-speed turbine and axial exhaust diffuser

Abstract

The invention provides a coupling structure of a high-speed turbine and an axial exhaust diffuser, which is applied to scale acceleration simulation design and can also be applied to industrial turbine design. The first bearing assembly comprises a front bearing seat connected with the inner casing of the front casing; the first thrust bearing is arranged on the front bearing seat, and the first thrust bearing is arranged at the front end of the rotor main shaft in a sleeving manner; the first radial bearing is arranged on the front bearing seat, and the first radial bearing is adjacent to the first thrust bearing; the second bearing assembly comprises a rear bearing seat which is connected with the inner casing of the rear casing; the second thrust bearing is arranged on the rear bearing seat, and the rear end of the rotor main shaft is sleeved with the second thrust bearing; the second radial bearing is arranged on the rear bearing seat, and the second radial bearing and the second thrust bearing are arranged adjacently; the first bearing assembly, the second bearing assembly and the rotor main shaft jointly form a simply supported beam structure.

Description

Technical Field

[0001] The present invention relates to the field of turbomachinery, and particularly to a coupling structure of a high-speed turbine and an axial exhaust diffuser. Background Art

[0002] As a core power device, the gas turbine occupies an important strategic position in the energy and power industry and the field of power machinery due to its characteristics of cleanness, flexibility, and high efficiency.

[0003] The exhaust diffuser is an important component of the gas turbine exhaust system. Its front-end inlet is connected to the last-stage turbine, guiding the airflow into the downstream exhaust pipe. Its function is to recover the residual velocity kinetic energy at the outlet of the last-stage turbine and convert it into static pressure at the outlet of the exhaust diffuser, thereby increasing the enthalpy drop of the turbine and improving the efficiency and output power of the whole machine.

[0004] The exhaust system is divided into radial flow type and axial flow type according to the exhaust direction. The radial exhaust structure is mostly used in medium and small gas turbines and consists of an annular diffuser and a radial exhaust volute; the axial exhaust structure is mostly used in heavy gas turbines above F class and consists of an annular diffuser and a conical diffuser.

[0005] The coupling structure of a high-speed turbine and an axial exhaust diffuser is one of the important research directions for improving the efficiency of the gas turbine exhaust system.

[0006] Regarding the coupling structure of the last-stage turbine of a gas turbine and an axial exhaust system, due to the limitations of some application scenarios such as high load, high speed, and direct drive, especially when assembled in the power system of a vehicle, its volume and weight should not be too large. Moreover, small-sized coupling components are not only convenient for manufacturing, installation, operation, and maintenance, but also can greatly reduce the manufacturing cost. However, to ensure that a small-sized high-speed turbine generates a high output power, it is required that the turbine can maintain a high-speed working state. In the coupling components of a small-sized high-speed turbine and an axial exhaust system in the prior art, the rotor main shaft usually adopts a cantilever beam support structure, that is, the support bearings of the rotor main shaft are all located on the same side of the turbine impeller disc. Under the design with a low scale ratio, due to the influence and restriction of many factors, the structural design scheme of this structure cannot withstand the various adverse effects and restrictions brought by high speed and high load.

[0007] For example: The rotor main shaft of the coupling structure of the existing high-speed turbine and the exhaust diffuser adopts a cantilever structure, with low support stiffness and poor anti-vibration stability performance of the system. In the same high-load transmission, the rotor main shaft and bearings of the cantilever structure are prone to mechanical fatigue and damage, and the bearing diameter on the side close to the wheel disc of the cantilever structure is greatly affected and restricted by the limiting speed, and the output end diameter of the rotor main shaft is restricted by the bearing diameter, and the number of stages of the turbine moving blades and the output power are also restricted, resulting in problems such as great design and processing difficulties. Summary of the Invention

[0008] To at least partially overcome the above-mentioned technical deficiencies of at least one or other inventions, embodiments of the present invention provide a coupling structure of a high-speed turbine and an axial exhaust diffuser, which can be applied to the scale-down speed-up simulation of turbines and diffusers and can still maintain a normal high-load working state after increasing the speed.

[0009] According to an inventive concept of an aspect disclosed by the present invention, a coupling structure of a high-speed turbine and an axial exhaust diffuser is provided, including: a rotor main shaft; a first bearing assembly, including: a front bearing housing connected to the inner housing of the front casing; a first thrust bearing disposed on the front bearing housing, the first thrust bearing sleeved on the front end of the rotor main shaft; a first radial bearing disposed on the front bearing housing, the first radial bearing being adjacent to the first thrust bearing; a second bearing assembly, including: a rear bearing housing connected to the inner housing of the rear casing; a second thrust bearing disposed on the rear bearing housing, the second thrust bearing sleeved on the rear end of the rotor main shaft; a second radial bearing disposed on the rear bearing housing, the second radial bearing being adjacent to the second thrust bearing; wherein, the first bearing assembly, the second bearing assembly and the rotor main shaft together form a simply supported beam structure.

[0010] According to some embodiments of the present invention, the first bearing assembly further includes a first preloading oil inlet ring, a preloading spring and an oil injection hole are arranged inside the first preloading oil inlet ring, the first preloading oil inlet ring is arranged between the first thrust bearing and the first radial bearing, and is used for applying a preloading force to the first thrust bearing and the first radial bearing and injecting lubricating oil, the preloading spring is used for applying a preloading force to the first thrust bearing and the first radial bearing to prevent the outer ring of the bearing from rotating; the oil injection hole is used for injecting lubricating oil to the first thrust bearing and the first radial bearing; and the second bearing assembly further includes a second preloading oil inlet ring, the second preloading oil inlet ring is arranged between the second thrust bearing and the second radial bearing, and is used for applying a preloading force to the second thrust bearing and the second radial bearing and injecting lubricating oil, and a preloading spring and an oil injection hole are arranged inside the second preloading oil inlet ring.

[0011] According to some embodiments of the present invention, the first thrust bearing and the second thrust bearing include angular contact ball bearings, and the first radial bearing and the second radial bearing include cylindrical roller bearings without ribs on the outer ring.

[0012] The coupling structure according to some embodiments of the present invention further includes: a middle casing disposed between the front casing and the rear casing, and the middle casing is connected to the front casing and the rear casing through flanges respectively.

[0013] The coupling structure according to some embodiments of the present invention further includes: a conical diffuser, which is connected to the rear casing through a flange.

[0014] According to some embodiments of the present invention, the middle casing includes: a middle casing housing; a single-stage stationary blade, which is arranged in a ring array on the inner sidewall of the middle casing housing; an impeller disk, which is arranged on the rotor main shaft and is located between the first bearing assembly and the second bearing assembly; and a single-stage moving blade, which is arranged in a ring array on the impeller disk.

[0015] According to some embodiments of the present invention, the middle casing further includes a front blade disk air seal body and a rear blade disk air seal body, and the front blade disk air seal body and the rear blade disk air seal body are respectively arranged on both sides of the impeller disk to ensure airtightness.

[0016] According to some embodiments of the present invention, the middle casing further includes: an anti-collision and wear-resistant insert, which is arranged on the inner sidewall of the middle casing housing, and an inner wall surface adapted to the shape of the single-stage moving blade is provided on the anti-collision and wear-resistant insert. The anti-collision and wear-resistant insert is made of copper alloy and is designed into a thin-walled hollow special-shaped hole structure, and aerated porous gypsum is filled in the hollow special-shaped hole.

[0017] According to some embodiments of the present invention, the first bearing assembly further includes: a first end cover, which is respectively arranged on both sides of the front bearing seat, and the two first end covers respectively abut against the first thrust bearing and the first radial bearing; a first air seal sleeve, which is arranged between the first end cover and the rotor main shaft, and the first air seal sleeve cooperates with the first end cover to realize the sealing of the first thrust bearing and the first radial bearing; the second bearing assembly further includes: a second end cover, which is respectively arranged on both sides of the rear bearing seat, and the two second end covers respectively abut against the second thrust bearing and the second radial bearing; a second air seal sleeve, which is arranged between the second end cover and the rotor main shaft, and the second air seal sleeve cooperates with the second end cover to realize the sealing of the second thrust bearing and the second radial bearing.

[0018] According to some embodiments of the present invention, the above-mentioned first bearing assembly further includes an axial preloading assembly, and the axial preloading assembly includes: a plurality of stud bolts arranged in an annular array, one end of which is screwed to the above-mentioned front bearing housing; a preloading spring sleeved on the above-mentioned stud bolts, one end of the above-mentioned preloading spring abuts against the above-mentioned first end cover; a limit cover sleeved on the above-mentioned stud bolts, the above-mentioned limit cover abuts against the other end of the above-mentioned preloading spring; and a hexagon nut screwed to the other end of the above-mentioned stud bolts; wherein, by tightening the above-mentioned hexagon nut, the above-mentioned preloading spring is compressed, so that the above-mentioned first end cover away from the above-mentioned front casing presses the above-mentioned first thrust bearing to generate an axial preloading force, and the axial load is transmitted to the above-mentioned second thrust bearing through the rotor main shaft. The axial preloading force can eliminate the clearance of the thrust bearing and apply a preset load to improve the working state of the thrust bearing.

[0019] For the coupling structure of the high-speed turbine and the axial exhaust diffuser according to the embodiments of the present invention, by respectively arranging two sets of bearing assemblies at the front end and the rear end of the rotor main shaft, forming a simply supported beam structure with the rotor main shaft, and cooperating with the combined method of separately separating the thrust bearing and the radial bearing, the wear of the bearing can be effectively reduced, so that the bearing can bear the working state of the high-speed rotation of the rotor main shaft for a long time, so as to ensure that the designed high-speed turbine after scale reduction and speed increase can adapt to the high-load working conditions at a higher speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematically shows a longitudinal sectional view of the coupling structure of the high-speed turbine and the axial exhaust diffuser according to the embodiments of the present invention;

[0021] Figure 2 is Figure 1 The partial enlarged view at A in;

[0022] Figure 3 is Figure 1 The partial enlarged view at B in;

[0023] Figure 4 is Figure 1 The partial enlarged view at C in;

[0024] Figure 5 Schematically shows a front view of the coupling structure of the high-speed turbine and the axial exhaust diffuser according to the embodiments of the present invention;

[0025] Figure 6 Schematically shows a side view of the coupling structure of the high-speed turbine and the axial exhaust diffuser according to the embodiments of the present invention;

[0026] Figure 7 Schematically shows a three-dimensional solid view of the rotor main shaft of the coupling structure of the high-speed turbine and the axial exhaust diffuser according to the embodiments of the present invention;

[0027] Figure 8 Schematic diagram showing the stator blade and blade root of the coupling structure of the high-speed turbine and axial exhaust diffuser according to an embodiment of the present invention;

[0028] Figure 9 Schematic diagram showing the rotor blade and blade root of the coupling structure of the high-speed turbine and axial exhaust diffuser according to an embodiment of the present invention;

[0029] Figure 10 Schematic diagram showing an enlarged view of the anti-collision and wear-resistant insert at the tip of the rotor blade of the coupling structure of the high-speed turbine and axial exhaust diffuser according to an embodiment of the present invention.

[0030] In the above-mentioned drawings, the meanings of the reference numerals are specifically as follows:

[0031] 1 - Rotor main shaft;

[0032] 2 - First bearing assembly;

[0033] 21 - Front bearing housing;

[0034] 211 - Oil inlet hole;

[0035] 22 - First thrust bearing;

[0036] 23 - First radial bearing;

[0037] 24 - First preloading oil ring;

[0038] 241 - Preloading spring;

[0039] 242 - Oil injection hole;

[0040] 25 - First end cover;

[0041] 26 - First gas seal sleeve;

[0042] 271 - Stud;

[0043] 272 - Preloading spring;

[0044] 273 - Limit cover;

[0045] 274 - Hexagonal nut;

[0046] 275 - Unidirectional thrust ball bearing;

[0047] 3 - Second bearing assembly;

[0048] 31 - Rear bearing housing;

[0049] 32 - Second thrust bearing;

[0050] 33 - Second radial bearing;

[0051] 34 - Second pre-tightening oil inlet ring;

[0052] 35 - Second end cover;

[0053] 36 - Second air seal sleeve;

[0054] 4 - Front housing;

[0055] 41 - Front support plate;

[0056] 5 - Rear housing;

[0057] 51 - Rear support plate;

[0058] 52 - Rear housing cover plate;

[0059] 6 - Middle housing;

[0060] 61 - Middle housing outer shell;

[0061] 62 - Single-stage stationary blade;

[0062] 63 - Impeller disk;

[0063] 64 - Single-stage rotating blade;

[0064] 65 - Air seal body in front of blade disk;

[0065] 66 - Air seal body behind blade disk;

[0066] 67 - Anti-collision and wear-resistant insert;

[0067] 68 - Adjustable guide vane assembly;

[0068] 7 - Conical diffuser;

[0069] J - Intake direction. Detailed implementation manners

[0070] To make the purpose, technical solutions and advantages of the disclosure of the present invention clearer and more understandable, the following further describes the present invention in detail with reference to specific embodiments and the accompanying drawings.

[0071] However, it should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. In the following detailed description, for the sake of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present invention. However, obviously, one or more embodiments can also be implemented without these specific details. In addition, in the following description, the description of well-known technologies is omitted to avoid unnecessarily confusing the concepts of the present invention.

[0072] The terms used herein are for describing specific embodiments only and are not intended to limit the present invention. The term "comprising" as used herein indicates the presence of features, steps, operations, but does not preclude the presence or addition of one or more other features.

[0073] In the case of using expressions such as "at least one of A, B, and C, etc.", generally it should be interpreted according to the meaning usually understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include but not be limited to a system having only A, only B, only C, having A and B, having A and C, having B and C, and / or having A, B, and C, etc.).

[0074] All terms used herein (including technical and scientific terms) have the meanings usually understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0075] The technical solution disclosed by the present invention is, in order to overcome the many deficiencies and drawbacks of the prior art as described above, to provide two sets of bearing assemblies at the front and rear ends of the rotor main shaft. The two sets of bearing assemblies and the rotor main shaft form a simply supported beam structure. By utilizing the characteristics of good stability, large support stiffness, and uniform load on the rotor main shaft and bearings of the simply supported beam structure, the faults caused by excessive wear and poor fit in the related art are solved. Moreover, the output end of the simply supported beam structure rotor main shaft is not restricted by the diameter of the disk side bearing, has a high limit speed, a large output power, is convenient for manufacturing, processing, installation and maintenance, and can enable the bearings to bear the long-term high-load and high-speed operating state of the rotor main shaft.

[0076] Figure 1 Schematically shows a longitudinal sectional view of the coupling structure of the high-speed turbine and the axial exhaust diffuser according to an embodiment of the present invention; Figure 2 is Figure 1 a partial enlarged view at position A in Figure 3 is Figure 1 a partial enlarged view at position B in Figure 4 is Figure 1 a partial enlarged view at position C in Figure 5 Schematically shows a front view of the coupling structure of the high-speed turbine and the axial exhaust diffuser according to an embodiment of the present invention; Figure 6 Schematically shows a side view of the coupling structure of the high-speed turbine and the axial exhaust diffuser according to an embodiment of the present invention.

[0077] According to the inventive concept of one aspect disclosed by the present invention, there is provided a coupling structure of a high-speed turbine and an axial exhaust diffuser, which is applied to scaled-up speed increase simulation design. As Figures 1 - 6As shown in the figure, the coupling structure includes: a rotor main shaft 1, a first bearing assembly 2, and a second bearing assembly 3. The first bearing assembly 2 includes: a front bearing housing 21, a first thrust bearing 22, and a first radial bearing 23. The front bearing housing 21 is connected to the inner housing of the front casing 4. The first thrust bearing 22 is arranged on the front bearing housing 21, and the first thrust bearing 22 is sleeved on the front end of the rotor main shaft 1. The first radial bearing 23 is arranged on the front bearing housing 21, and the first radial bearing 23 is arranged adjacent to the first thrust bearing 22. The second bearing assembly 3 includes: a rear bearing housing 31, a second thrust bearing 32, and a second radial bearing 33. The rear bearing housing 31 is connected to the inner housing of the rear casing 5. The second thrust bearing 32 is arranged on the rear bearing housing 31, and the second thrust bearing 32 is sleeved on the rear end of the rotor main shaft 1. The second radial bearing 33 is arranged on the rear bearing housing 31, and the second radial bearing 33 is arranged adjacent to the second thrust bearing 32. The first bearing assembly 2, the second bearing assembly 3, and the rotor main shaft 1 together form a simple supported beam structure.

[0078] In this embodiment, by separately arranging two sets of bearing assemblies at the front end and the rear end of the rotor main shaft 1, a simple supported beam structure is formed with the rotor main shaft 1. The combined method of separating the thrust bearing and the radial bearing can reasonably distribute the loads of each bearing, effectively reduce the wear of the bearings, enable the bearings to withstand the working state of the high-speed rotation of the rotor main shaft 1 for a long time, so as to ensure that the scaled-up speed-increasing structure scheme can meet the design requirements of higher speeds and higher loads.

[0079] According to some embodiments of the present invention, the thrust bearings (the first thrust bearing 22 and the second thrust bearing 32) are used to bear the axial load during the high-speed rotation of the coupling structure, so as to limit that the rotor main shaft 1 can rotate but cannot axially move.

[0080] According to some embodiments of the present invention, the radial bearings (the first radial bearing 23 and the second radial bearing 33) are used to bear the radial load, support the weight of the rotor main shaft 1 and the centrifugal force caused by the mass imbalance of the rotor main shaft 1, and limit the radial position of the rotor.

[0081] Figure 7 A three-dimensional solid diagram of the rotor main shaft of the coupling structure of the high-speed turbine and the axial exhaust diffuser according to the embodiment of the present invention is schematically shown.

[0082] According to some embodiments of the present invention, as Figures 1 - 4 and Figure 7 shown, the front and rear ends of the rotor main shaft 1 rely on the front bearing housing 21 and the rear bearing housing 31 to be connected to the inner housings of the front casing 4 and the rear casing 5.

[0083] According to some embodiments of the present invention, both ends of the rotor main shaft 1 are placed on the first bearing assembly 2 and the second bearing assembly 3 to form a simply supported beam structure. The bearing assemblies only restrict the radial displacement and axial displacement of the beam, and the beam (rotor main shaft 1) can rotate freely.

[0084] According to some embodiments of the present invention, the first bearing assembly 2 further includes a first preloading oil inlet ring 24. The first preloading oil inlet ring 24 is arranged between the first thrust bearing 22 and the first radial bearing 23 to apply a preloading force to the first thrust bearing 22 and the first radial bearing 23 to prevent the outer ring of the bearing from rotating. The second bearing assembly 3 further includes a second preloading oil inlet ring 34. The second preloading oil inlet ring 34 is arranged between the second thrust bearing 32 and the second radial bearing 33 to apply a preloading force to the second thrust bearing 32 and the second radial bearing 33 to prevent the outer ring of the bearing from rotating.

[0085] According to some embodiments of the present invention, the front and rear ends of the first preloading oil inlet ring 24 are respectively in contact with the first thrust bearing 22 and the first radial bearing 23. A group of preloading springs 241 evenly distributed in the circumferential direction are arranged inside the first preloading oil inlet ring 24 to apply a preloading force to the first thrust bearing 22 and the first radial bearing 23 to prevent the outer ring of the bearing from rotating. Oil injection holes 242 are provided at the front and rear of the first preloading oil inlet ring 24 to inject lubricating oil into the first thrust bearing 22 and the first radial bearing 23 at the same time. The oil injection holes 242 of the first preloading oil inlet ring 24 are connected to the oil supply system through the front bearing housing 21 and the oil inlet hole 211 on the front bearing housing 21. Similarly, the front and rear ends of the second preloading oil inlet ring 34 are respectively in contact with the second thrust bearing 32 and the second radial bearing 33. A group of preloading springs 241 evenly distributed in the circumferential direction are arranged inside the second preloading oil inlet ring 34 to apply a preloading force to the second thrust bearing 32 and the second radial bearing 33 to prevent the outer ring of the bearing from rotating. Oil injection holes 242 are provided at the front and rear of the second preloading oil inlet ring 34 to inject lubricating oil into the second thrust bearing 32 and the second radial bearing 33 at the same time. The oil injection holes 242 of the second preloading oil inlet ring 34 are connected to the oil supply system through the rear bearing housing 31 and the oil inlet hole 211 on the rear bearing housing 31.

[0086] According to some embodiments of the present invention, the first thrust bearing 22 and the second thrust bearing 32 include angular contact ball bearings, and the first radial bearing 23 and the second radial bearing 33 include cylindrical roller bearings without flanges on the outer ring.

[0087] According to some preferred embodiments of the present invention, the first thrust bearing 22 and the second thrust bearing 32 are angular contact ball bearings. A relatively small clearance fit is adopted between the outer ring of the thrust bearing and the bearing housing.

[0088] According to some embodiments of the present invention, there are raceways on both the inner and outer rings of the angular contact ball bearing, and the inner and outer rings can make a small amount of relative displacement along the axial direction of the bearing. The angular contact ball bearing has a relatively high limiting speed and can bear both radial load and axial load, or can bear pure axial load. Its axial load capacity is determined by the contact angle and increases with the increase of the contact angle.

[0089] According to some preferred embodiments of the present invention, the first radial bearing 23 and the second radial bearing 33 are cylindrical roller bearings without flange on the outer ring (type N). A relatively small clearance fit is adopted between the outer ring of the radial bearing and the bearing housing.

[0090] According to some embodiments of the present invention, the rollers and raceways of the cylindrical roller bearing without flange on the outer ring (type N) of the present invention are in line contact, with large radial load-carrying capacity, suitable for bearing heavy loads and impact loads; small friction coefficient and relatively high limiting speed; the outer ring of the bearing can move axially, can adapt to the relative position change of the shaft and the housing caused by thermal expansion or installation error, and can be used as a free-end support; the inner ring or the outer ring can be separated, which is convenient for installation and disassembly.

[0091] According to some embodiments of the present invention, the coupling structure of the high-speed turbine and the axial exhaust diffuser further includes: a middle casing 6. The middle casing 6 is arranged between the front casing 4 and the rear casing 5, and both between the middle casing 6 and the front casing 4 and between the middle casing 6 and the rear casing 5 are connected by flanges.

[0092] According to some embodiments of the present invention, the casings are connected by flanges, which is convenient for disassembly, has high strength and good sealing performance.

[0093] According to some embodiments of the present invention, the interior of the front casing 4 includes a number of evenly distributed front support plates 41. The front support plates 41 are used to connect the inner and outer wall surfaces of the front casing 4 and provide support for the front bearing housing 21; the interior of the rear casing 5 includes a number of evenly distributed rear support plates 51 and a rear casing cover plate 52. The rear support plates 51 are used to connect the inner and outer wall surfaces of the rear casing 5 and provide support for the rear bearing housing 31.

[0094] According to some embodiments of the present invention, the interior of the middle casing 6 includes an adjustable guide vane assembly 68. The adjustable guide vane assembly 68 has a simple structure and small energy loss, and can achieve real-time adjustment.

[0095] According to some embodiments of the present invention, the coupling structure of the high-speed turbine and the axial exhaust diffuser further includes: a conical diffuser 7. The conical diffuser 7 is connected to the rear casing 5 by a flange.

[0096] According to some embodiments of the present invention, the rear casing 5 is connected to the conical diffuser 7, and the two also have a pneumatic thermodynamics matching relationship. The aerodynamic shapes of the inner and outer wall surfaces of the rear casing 5 and the rear support plate 51, as well as the aerodynamic shape of the conical diffuser 7, are designed and optimally combined by known pneumatic thermodynamics numerical calculation methods to reasonably organize the flow field and optimize the flow characteristics of the axial exhaust system.

[0097] According to some embodiments of the present invention, the conical diffuser 7 has a simple structure and is easy to optimize the flow state. The cone angle or area ratio can be selected in the design of the conical diffuser 7 according to parameters.

[0098] Figure 8 Schematically shows a schematic diagram of the single-stage stationary blade 62 and the blade root of the coupling structure of the high-speed turbine and the axial exhaust diffuser according to an embodiment of the present invention. Figure 9 Schematically shows a schematic diagram of the single-stage moving blade 64 and the blade root of the coupling structure of the high-speed turbine and the axial exhaust diffuser according to an embodiment of the present invention.

[0099] According to some embodiments of the present invention, as Figure 8 、 Figure 9 shown, the middle casing 6 includes: a middle casing outer shell 61, a single-stage stationary blade 62, an impeller disk 63, and a single-stage moving blade 64. The single-stage stationary blade 62 is arranged in an annular array on the inner side wall of the middle casing outer shell 61. The impeller disk 63 is arranged on the rotor main shaft 1. The single-stage moving blade 64 is arranged in an annular array on the impeller disk 63.

[0100] In this embodiment, the function of the single-stage stationary blade 62 is to make the high-temperature gas expand and accelerate in its gas flow channel along the intake direction J, convert the internal energy of the gas into kinetic energy, and then drive the single-stage moving blade 64 on the rotor main shaft 1 to rotate and do work. The function of the single-stage moving blade 64 is to convert the energy of the high-temperature gas into the rotational mechanical energy of the rotor main shaft 1 and output it externally.

[0101] According to some embodiments of the present invention, the middle casing 6 further includes: a blade disk front air seal body 65 and a blade disk rear air seal body 66. The blade disk front air seal body 65 and the blade disk rear air seal body 66 are respectively arranged on both sides of the impeller disk 63 to ensure airtightness. The blade disk front air seal body 65 is directly connected to the inner casing of the front casing 4 through a flange. The blade disk rear air seal body 66 is directly connected to the inner casing of the rear casing 5 through a flange.

[0102] In this embodiment, the air seal body can prevent steam from flowing through the gap without doing work and improve the efficiency of the unit.

[0103] Figure 10 Schematically shows an enlarged schematic diagram of the anti-collision and anti-abrasion insert 67 at the tip of the moving blade of the coupling structure of the high-speed turbine and the axial exhaust diffuser according to an embodiment of the present invention.

[0104] According to some embodiments of the present invention, as Figure 10 shown, the intermediate casing 6 further includes: an anti-collision and wear-resistant insert 67. The anti-collision and wear-resistant insert 67 is disposed on the mounting groove of the inner sidewall of the intermediate casing housing 61. The anti-collision and wear-resistant insert 67 is provided with an inner wall surface adapted to the shape of the top of the single-stage moving blade 64. The material of the anti-collision and wear-resistant insert 67 is aluminum alloy, which has a thin-walled hollow special-shaped hole structure. The hollow special-shaped hole inside it is filled with aerated porous gypsum. When the moving blade rubs against the anti-collision and wear-resistant insert 67, since the hardness of the material used for the anti-collision and wear-resistant insert 67 is much lower than that of the moving blade material, and it is designed with a thin-walled hollow special-shaped hole structure, the wall thickness of the metal material forming the inner wall surface of the casing is very thin. Once the high-speed rotating moving blade rubs against it, it can easily cause it to be dented and deformed and yield, which can effectively protect the high-speed rotating moving blade.

[0105] According to some embodiments of the present invention, the first bearing assembly 2 further includes: a first end cover 25 and a first gas seal sleeve 26. The second bearing assembly 3 further includes: a second end cover 35 and a second gas seal sleeve 36. The first end cover 25 is respectively disposed on both sides of the front bearing housing 21. The two first end covers 25 respectively abut against the first thrust bearing 22 and the first radial bearing 23. The first gas seal sleeve 26 is disposed between the first end cover 25 and the rotor main shaft 1. The first gas seal sleeve 26 cooperates with the first end cover 25 to achieve the sealing of the first thrust bearing 22 and the first radial bearing 23. The second end cover 35 is respectively disposed on both sides of the rear bearing housing 31. The two second end covers 35 respectively abut against the second thrust bearing 32 and the second radial bearing 33. The second gas seal sleeve 36 is disposed between the second end cover 35 and the rotor main shaft 1. The second gas seal sleeve 36 cooperates with the second end cover 35 to achieve the sealing of the second thrust bearing 32 and the second radial bearing 33.

[0106] According to some embodiments of the present invention, the bearing end cover is used to fix the bearing, adjust the bearing clearance and bear the axial force.

[0107] According to some embodiments of the present invention, the first bearing assembly 2 further includes: a preloaded axial load assembly. The preloaded axial load assembly includes: a stud 271, a preloaded spring 272, a limit cover 273, and a hexagon nut 274. The stud 271 has one end screwed to the front bearing housing 21, and several studs are distributed in an array. The preloaded spring 272 is sleeved on the stud 271, and one end of the preloaded spring 272 abuts against the first end cover 25. The limit cover 273 is sleeved on the stud 271, and the limit cover 273 abuts against the other end of the preloaded spring 272. The hexagon nut 274 is screwed to the other end of the stud 271. By tightening the hexagon nut 274, the preloaded spring 272 is compressed, so that the first end cover 25 away from the front casing 4 presses the first thrust bearing 22, generating a preloaded axial load, and the preloaded axial load is transmitted to the second thrust bearing 32 through the rotor main shaft 1.

[0108] In this embodiment, compared with the related art where no preloaded axial load structure is provided, the rolling elements of the bearings on the rotor main shaft are prone to slipping, and the heat generated by sliding friction during high-speed rotation in the inner raceway is high, causing serious damage to the components. In the present invention, the added preloaded axial load structure can transmit the load to the first thrust bearing 22 and the second thrust bearing 32, ensuring the optimal operating state of the rotor main shaft 1.

[0109] According to some embodiments of the present invention, the preloaded load structure is arranged at the front end of the first end cover 25 away from the front casing 4, and the preloaded spring 272, the limit cover 273, the single-direction thrust ball bearing 275 and the first bearing housing 21 are connected through the stud 271 and the hexagon nut 274 to jointly form the preloaded axial load structure.

[0110] The function of the preloaded axial load structure is mainly to utilize the pre-tightening force generated after pre-compression of several preloaded springs 272 evenly distributed along the circumference. Through a series of related components, the pre-tightening force is transmitted from the front end to the rear end of the rotor main shaft 1 and acts on the second thrust bearing 32 at the rearmost end. An appropriate preloaded axial load can prevent bearing slipping, heating, ablation and accelerated wear under no-load or low-load conditions of a high-speed turbine, and can ensure the long-term safe operation of the bearing group under various operating conditions.

[0111] The coupling structure of the high-speed turbine and the axial exhaust diffuser in the embodiment of the present invention adopts a simply supported beam structure. The front bearing housing is supported by the front support plate 41, and the rear bearing housing is supported by the rear support plate 51. The bearing loads are reasonably distributed, the support stiffness is large, the high-speed operation is stable, and the anti-vibration performance is good. The simply supported beam structure is not only applicable to single-stage turbines, but also applicable to double-stage or multi-stage turbines. Compared with the existing cantilever beam structure, its applicability is more extensive. The simply supported beam structure adopted in the present invention provides a practical and effective technical solution for high-speed turbines with axial exhaust and various types of impeller machinery.

[0112] The coupling structure of the high-speed turbine and the axial exhaust diffuser according to the embodiments of the present invention has the following technical effects compared with the prior art:

[0113] 1. Some existing rotor main shafts adopt a cantilever structure, with poor stability. In the same load transmission, the rotor main shaft with a cantilever structure is prone to mechanical fatigue. In addition, the diameter of the bearing near the wheel disc side of the cantilever structure is greatly affected by the limit speed, which requires a high machining accuracy at the output end of the rotor main shaft and is difficult to machine. The rotor main shaft with a simply supported beam structure adopted by the present invention has good system stability and uniform bearing load, thus avoiding failures caused by excessive wear and poor fit. In addition, the output end of the rotor main shaft with a simply supported beam structure is not affected by the wheel disc diameter and is convenient to machine. Considering comprehensively, the simply supported beam structure is more suitable for the rotor main shaft with high speed.

[0114] 2. The present invention includes two sets of identical bearing groups, which are respectively arranged at the front end and the rear end of the rotor main shaft according to the characteristics of the simply supported beam structure. Each set of bearing groups is composed of an angular contact ball bearing as a thrust bearing and a cylindrical roller bearing without a flange on the outer ring as a radial bearing. This combined way of separating the thrust bearing and the radial bearing can effectively reduce the wear of the bearing and enable the bearing to bear the working state of the high-speed rotation of the rotor main shaft for a long time.

[0115] 3. The present invention is provided with a preloading structure. For the structure without preloading, the bearing rolling elements are prone to slip, and the heat generated by sliding friction is high when rotating at high speed on the inner track, which seriously damages the components. The preloading structure provided by the present invention can transmit the preloaded axial load to the thrust bearing, ensure a good rolling state of the bearing, avoid slipping, heating, ablation and accelerated wear, and ensure long-term safe operation.

[0116] 4. An anti-collision and anti-abrasion insert is provided at the top of the single-stage moving blade of the present invention. The copper alloy material used for the anti-collision and anti-abrasion insert is filled with aerated porous gypsum in the special-shaped holes inside, and its hardness is much lower than that of the moving blade material. In addition, the special-shaped holes inside the anti-abrasion insert are relatively large, and the metal material on the side of the casing inner wall is relatively thin. The high-speed rotating blade can easily cause it to dent, deform and yield when rubbing against it, which can effectively protect the high-speed rotating blade.

[0117] 5. The high-speed turbine and the axial exhaust diffuser of the present invention are not only applicable to the rotor main shaft with single-stage moving blades, but also applicable to the rotor main shaft with double-stage or multi-stage moving blades, and the output power is significantly higher than that of the prior art.

[0118] So far, the embodiments of the present invention have been described in detail with reference to the accompanying drawings. It should be noted that, in the accompanying drawings or the text of the specification, the implementation manners that are not depicted or described are all forms known to those of ordinary skill in the art, and no detailed description is given. In addition, the above definitions of each component are not limited to the specific structures, shapes or manners mentioned in the embodiments, and those of ordinary skill in the art can make simple changes or substitutions thereto.

[0119] It should also be noted that, in the specific embodiments of the present invention, unless otherwise known to the contrary, the numerical parameters in this specification and the appended claims are approximate values and can be changed according to the required characteristics obtained through the content of the present invention. Specifically, all the numbers representing dimensions, range conditions, etc. of the components used in the specification and the claims should be understood to be modified by the term "about" in all cases. Generally, the meaning expressed is that it includes a change of ±10% in some embodiments, a change of ±5% in some embodiments, a change of ±1% in some embodiments, and a change of ±0.5% in some embodiments for a specific quantity.

[0120] Those skilled in the art can understand that the features recited in the various embodiments and / or claims of the present invention can be combined or combined in various ways, even if such combinations or combinations are not explicitly recited in the present invention. In particular, without departing from the spirit and teachings of the present invention, the features recited in the various embodiments and / or claims of the present invention can be combined and combined in various ways. All such combinations and / or combinations fall within the scope of the present invention.

[0121] The above specific embodiments have further detailed the purpose, technical solution and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A coupling structure of a high-speed turbine and an axial exhaust diffuser, which is applied to scaled-up speed-up simulation design or industrial turbine design, is characterized in that Comprising: Rotating shaft spindle (1); The first bearing assembly (2), comprising: Front bearing housing (21), connected to the inner housing of the front casing (4); The first thrust bearing (22), arranged on the front bearing housing (21), and the first thrust bearing (22) is sleeved on the front end of the rotating shaft spindle (1); The first radial bearing (23)(23), arranged on the front bearing housing (21), and the first radial bearing (23) is arranged adjacent to the first thrust bearing (22); The second bearing assembly (3), comprising: Rear bearing housing (31), connected to the inner housing of the rear casing (5); The second thrust bearing (32), arranged on the rear bearing housing (31), and the second thrust bearing (32) is sleeved on the rear end of the rotating shaft spindle (1); The second radial bearing (33), arranged on the rear bearing housing (31), and the second radial bearing (33) is arranged adjacent to the second thrust bearing (32); Wherein, the first bearing assembly (2), the second bearing assembly (3) and the rotating shaft spindle (1) together form a simply supported beam structure.

2. The coupling structure of the high-speed turbine and the axial exhaust diffuser according to claim 1, characterized in that The first bearing assembly (2) further includes a first preloading oil inlet ring (24), and a preloading spring (241) and an oil injection hole (242) are arranged inside the first preloading oil inlet ring (24); the first preloading oil injection ring (24) is arranged between the first thrust bearing (22) and the first radial bearing (23), the preloading spring (241) is used to apply a preloading force to the first thrust bearing (22) and the first radial bearing (23) to prevent the outer ring of the bearing from rotating, and the oil injection hole (242) is used to inject lubricating oil into the first thrust bearing (22) and the first radial bearing (23); and The second bearing assembly (3) further includes a second preloading oil inlet ring (34), and a preloading spring (241) and an oil injection hole (242) are arranged inside the second preloading oil inlet ring (34); the first preloading oil injection ring (34) is arranged between the second thrust bearing (32) and the second radial bearing (33), the preloading spring (241) is used to apply a preloading force to the second thrust bearing (32) and the second radial bearing (33) to prevent the outer ring of the bearing from rotating, and the oil injection hole (242) is used to inject lubricating oil into the second thrust bearing (32) and the second radial bearing (33).

3. The coupling structure of the high-speed turbine and the axial exhaust diffuser according to claim 1 or 2, characterized in that, The first thrust bearing (22) and the second thrust bearing (32) include angular contact ball bearings, and the first radial bearing (32) and the second radial bearing (33) include cylindrical roller bearings without outer ring flanges.

4. The coupling structure of the high-speed turbine and the axial exhaust diffuser according to claim 1, characterized in that, Further comprising: The middle casing (6), arranged between the front casing (4) and the rear casing (5), and the middle casing (6) is connected to the front casing (4) and the middle casing (6) is connected to the rear casing (5) by flanges respectively.

5. The coupling structure of the high-speed turbine and the axial exhaust diffuser according to claim 1, wherein, Further comprising: The conical diffuser (7), connected to the rear casing (5) by a flange.

6. The coupling structure of the high-speed turbine and the axial exhaust diffuser according to claim 4, characterized in that, The middle casing (6) includes: The middle casing outer shell (61); The single-stage static blades (62) are arranged in an annular array on the inner side wall of the intermediate casing housing (61); The impeller disk (63) is arranged on the rotor main shaft (1) and is located between the first bearing assembly (2) and the second bearing assembly (3); and The single-stage moving blades (64) are arranged in an annular array on the impeller disk (63).

7. The coupling structure of the high-speed turbine and the axial exhaust diffuser according to claim 6, wherein, The intermediate casing (6) further includes: A front blade disk air seal body (65) and a rear blade disk air seal body (66). The front blade disk air seal body (65) and the rear blade disk air seal body (66) are respectively arranged on both sides of the impeller disk (63) to ensure airtightness.

8. The coupling structure of the high-speed turbine and the axial exhaust diffuser according to claim 6, characterized in that, The intermediate casing (6) further includes: An anti-collision and wear-resistant insert (67) is arranged on the inner side wall of the intermediate casing housing (61). The anti-collision and wear-resistant insert (67) has an inner wall surface adapted to the shape of the top of the single-stage moving blade (64). The anti-collision and wear-resistant insert (67) is made of copper alloy and has a thin-walled hollow special-shaped hole structure with aerated porous gypsum filled inside to protect the single-stage moving blade (64).

9. The coupling structure of the high-speed turbine and the axial exhaust diffuser according to claim 1 or 2, wherein The first bearing assembly (2) further includes: The first end covers (25) are respectively arranged on both sides of the front bearing housing (21), and the two first end covers (25) respectively abut against the first thrust bearing (22) and the first radial bearing (23); The first air seal sleeve (26) is arranged between the first end cover (25) and the rotor main shaft (1), and the first air seal sleeve (26) cooperates with the first end cover (25) to achieve the sealing of the first thrust bearing (22) and the first radial bearing (23); The second bearing assembly (3) further includes: The second end covers (35) are respectively arranged on both sides of the rear bearing housing (31), and the two second end covers (35) respectively abut against the second thrust bearing (32) and the second radial bearing (33); The second air seal sleeve (36) is arranged between the second end cover (35) and the rotor main shaft (1), and the second air seal sleeve (36) cooperates with the second end cover (35) to achieve the sealing of the second thrust bearing (32) and the second radial bearing (33).

10. The coupling structure of the high-speed turbine and the axial exhaust diffuser according to claim 9, characterized in that The first bearing assembly (2) far from the front casing (4) further includes: a pre-applied axial load assembly, and the pre-applied axial load assembly includes: The stud (271), one end of which is screwed to the front bearing housing (21); the stud 271, and several are distributed in an array; The pre-loading spring (272) is sleeved on the stud (271), and one end of the pre-loading spring (272) abuts against the first end cover (25); The limit cover (273) is sleeved on the stud (271), and the limit cover (273) abuts against the other end of the pre-loading spring (272); and The hexagon nut (274) is screwed to the other end of the stud (271); Among them, by tightening the hexagon nut (274), the preloading spring (272) is compressed, so that the first end cover (25) away from the front fuselage (4) presses the first thrust bearing (22), generating a preloaded axial load, and through the rotor main shaft (1), the preloaded axial load is transmitted to the second thrust bearing (32).

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