A starting structure for a low-pressure rotor of a belt-driven gas turbine

Abstract

The present invention belongs to the technical field of gas turbines, and specifically relates to a starting structure for driving a low-pressure rotor of a gas turbine, including a starting power system and a starting connection assembly; the starting connection assembly includes a torque output shaft, a bearing seat, a front bearing, a rear bearing and an overrunning clutch; the bearing seat is in a circular ring shape with a convex middle portion, and the middle outer side of the bearing seat is fixedly connected to the front end of the gas turbine casing; the front bearing is connected between the front end of the bearing seat and the torque output shaft, and the rear bearing is connected between the rear end of the bearing seat and the torque output shaft; the front end of the torque output shaft is transmission-connected to the starting power system, and the rear end of the torque output shaft is connected to the front shaft neck of the low-pressure compressor through an overrunning clutch to drive the low-pressure rotor. The starting structure in this scheme starts the gas turbine by driving the low-pressure rotor of the gas turbine. Compared with the high-pressure starting method, the gas turbine can be started at a lower rotor speed, with lower restrictions on installation space, and lower maintenance and debugging difficulties.

Description

Technical Field

[0001] The invention belongs to the technical field of gas turbines, and in particular relates to a starting structure for a low-pressure rotor of a gas turbine. Background Art

[0002] The starting of a gas turbine is achieved by providing power through an external motor, which acts on the gas turbine rotor, thereby driving the gas turbine rotor to rotate and finally achieve the effect of starting the gas turbine. At present, most of the starting structures of gas turbines are high-pressure starting structures, that is, the external starting motor transmits power to the high-pressure rotor, and when the gas flow and pressure in front of the combustion chamber reach the predetermined value, ignition is completed, so that the gas turbine reaches the self-running state.

[0003] However, due to the size and structure of the high-pressure blades, in order to make the gas flow and pressure in front of the combustion chamber reach the predetermined values, the high-pressure rotor speed needs to reach above 3750r / min to start the gas turbine; and the accessory transmission system used for torque transmission and the bevel gear plate coaxially connected to the high-pressure rotor will also rotate synchronously with the high-pressure rotor.

[0004] In addition, since the high-pressure rotor is located between the low-pressure compressor and the low-pressure turbine, the internal space of the high-pressure rotor is limited, so the size of the accessory drive system extending into the gas turbine casing must be reasonable, resulting in the transmission ratio of the accessory drive system to the bevel gear plate being often above 3. On this basis, when the rated operating conditions of the gas turbine are reached, the speed of some parts of the accessory drive system will be as high as 22980r / min, which is very likely to generate a lot of vibration, which poses a huge test to the safety, stability and service life of the accessory drive system and the gas turbine during operation.

[0005] Finally, due to the special installation location of the accessory transmission system and the high requirements for installation accuracy, multiple adjustments are often required to meet the standards. During each adjustment or failure, the front support point, low-pressure compressor, high-pressure compressor, combustion chamber, high-pressure turbine, and low-pressure turbine need to be disassembled and inspected, and then all reinstalled, which requires a large workload, a long cycle, and high costs.

[0006] Therefore, it is necessary to design a starting structure with a rotating gas turbine low-pressure rotor. Summary of the invention

[0007] In order to solve the above problems existing in the prior art, the present invention provides a starting structure for a low-pressure rotor of a gas turbine.

[0008] The technical solution adopted by the present invention is:

[0009] A starting structure for a low-pressure rotor of a belt-driven gas turbine includes a starting power system and a starting connection assembly;

[0010] The low-pressure rotor is rotatably connected to the gas turbine casing, and includes a low-pressure compressor and a low-pressure turbine connected to each other, and a low-pressure compressor front journal is arranged at the front end of the low-pressure compressor;

[0011] The starting connection assembly includes a torque output shaft, a bearing seat, a front bearing, a rear bearing and an overrunning clutch; the bearing seat is in a circular ring shape with a convex middle portion, and the outer middle portion of the bearing seat is fixedly connected to the front end of the gas turbine casing; the front bearing is connected between the front end of the bearing seat and the torque output shaft, and the rear bearing is connected between the rear end of the bearing seat and the torque output shaft; the front end of the torque output shaft is transmission-connected to the starting power system, and the rear end of the torque output shaft is connected to the front shaft neck of the low-pressure compressor through an overrunning clutch to rotate the low-pressure rotor.

[0012] As an alternative or supplement to the above starting structure: the front bearing and the rear bearing are lubricated by plastic grease, a front oil sealing assembly is arranged on the front side of the front bearing, and a rear oil sealing assembly is arranged on the rear side of the rear bearing.

[0013] As an alternative or supplement to the above-mentioned starting structure: the front oil seal assembly and the rear oil seal assembly both include a sealing cover, a leather cup seal and a retaining ring; the sealing cover is in a circular ring shape and is fixed to the end face of the bearing seat by bolts; the leather cup seal is installed on the inner side of the sealing cover, and the leather cup seal is sleeved on the outside of the torque output shaft to achieve sealing; the retaining ring is installed on the sealing cover and is used to prevent the leather cup seal from falling off the sealing cover.

[0014] As an alternative or supplement to the above starting structure: an annular groove is provided on the inner side of the middle part of the bearing seat, and the annular groove is used to accommodate plastic grease.

[0015] As an alternative or supplement to the above starting structure: a bearing spacer sleeve is arranged outside the torque output shaft, the bearing spacer sleeve is in a circular ring shape, the front end of the bearing spacer sleeve abuts against the inner ring of the front bearing, and the rear end of the bearing spacer sleeve abuts against the inner ring of the rear bearing.

[0016] As an alternative or supplement to the above starting structure: a step surface is provided in the middle of the torque output shaft, and the rear end of the inner ring of the rear bearing abuts against the step surface.

[0017] As an alternative or supplement to the above-mentioned starting structure: the torque output shaft is tubular, and a locking assembly is connected to the front end of the torque output shaft; a key tooth is arranged on the inner side of the front end of the torque output shaft for key connection to the starting power system; the locking assembly includes a first slotted large nut, a first stopping gasket and a sealing distance sleeve; the sealing distance sleeve is arranged on the outer side of the front end of the torque output shaft and abuts against the inner ring of the front bearing; a thread is arranged on the outer side of the front end of the torque output shaft to connect the first slotted large nut, so that the first slotted large nut is pressed against the front end of the sealing distance sleeve through the first stopping gasket, and the protruding tongue on the inner side of the first stopping gasket is clamped with the groove corresponding to the torque output shaft to limit the rotation of the first stopping gasket; the stopping tongue on the first stopping gasket can be bent into the groove on the outer side of the first slotted large nut to lock the first slotted large nut.

[0018] As an alternative or supplement to the above-mentioned starting structure: a flat key, a second stop washer and a second slotted large nut are provided at the connection between the overrunning clutch and the front shaft neck of the low-pressure compressor; the second slotted large nut is threadedly connected to the thread at the front end of the low-pressure compressor front shaft neck, and is pressed against the inner ring of the overrunning clutch through the second stop washer, and the inner ring of the overrunning clutch is connected to the key of the front shaft neck of the low-pressure compressor through the flat key.

[0019] The beneficial effects of the present invention are:

[0020] 1. The starting structure in this scheme starts the gas turbine by driving the low-pressure rotor of the gas turbine. Since the structure and size of the low-pressure blades are larger, the gas turbine can be started at a lower rotor speed;

[0021] 2. Since the starting structure in this scheme adopts the low-pressure rotor drive mode, the starting structure can be directly installed in front of the gas turbine, with lower installation space restrictions and lower maintenance and debugging difficulties;

[0022] 3. This solution has a lower rotation speed requirement for the starting structure. When only plastic grease is used at the bearing of the torque output shaft, the lubrication requirements can be met. No additional lubricating oil and related lubricating oil circuits are required, which effectively reduces the structural complexity of the starting structure and the cost of use and maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below.

[0024] Figure 1 It is the usage state diagram of the starting structure in this scheme;

[0025] Figure 2 It is a detailed structural diagram of the starting connection assembly;

[0026] Figure 3 It is a detailed structural diagram of the oil sealing assembly and the locking assembly;

[0027] Figure 4 This is an example diagram of a high-pressure rotor starting structure;

[0028] Figure 5 This is a detailed structural diagram of the transmission gear train.

[0029] In the figure: 1-starting power system; 2-starting connection assembly; 21-torque output shaft; 22-bearing distance sleeve; 23-rear bearing; 24-overrunning clutch; 25-bearing seat; 26-front bearing; 27-rear oil seal assembly; 28-front oil seal assembly; 281-sealing cover; 282-leather cup seal; 283-retaining ring; 29-locking assembly; 291-first slotted large nut; 292-first stop washer; 293-sealing distance sleeve; 3-gas turbine casing; 4-low-pressure compressor; 5 -high-pressure rotor; 6-low-pressure turbine; 7-low-pressure compressor front journal; 8-flat key; 9-second stop washer; 10-second slotted large nut; 11-accessory transmission system; 12-transmission gear train; 121-transmission gear; 122-transmission system mounting seat; 123-first adjustment pad; 124-end nut; 125-bearing mounting seat; 126-transmission bearing; 127-first distance sleeve; 128-rod bearing; 13-high-pressure compressor front journal; 14-bevel gear plate; 15-second adjustment pad. DETAILED DESCRIPTION

[0030] The technical solution in this embodiment will be clearly and completely described below in conjunction with the accompanying drawings. The described embodiments are only some of the embodiments, not all of them. Based on the embodiments in this solution, all other embodiments obtained by ordinary technicians in this field without making creative work are within the protection scope of this solution.

[0031] like Figure 4-5 As shown, the gas turbine includes components such as a gas casing, a low-pressure rotor and a high-pressure rotor 5, wherein the low-pressure rotor and the high-pressure rotor 5 are both rotatably arranged in the gas casing, and the low-pressure rotor includes a low-pressure compressor 4 and a low-pressure turbine 6 that are interconnected, and the high-pressure rotor 5 is rotatably arranged between the low-pressure compressor 4 and the low-pressure turbine 6.

[0032] At present, most gas turbines tend to start in a high-voltage starting mode, that is, the power of the starter motor is transmitted to the high-pressure rotor 5 through the accessory transmission system 11. When the speed of the high-pressure rotor 5 reaches 3750r / min or more, the gas turbine can be guaranteed to run automatically, thereby realizing the start of the gas turbine. However, this high-voltage starting mode has the problems of high speed required for driving, high requirements for the structure of the accessory transmission system 11, high requirements for the installation accuracy of the structure of the accessory transmission system 11, high difficulty in debugging, and easy vibration.

[0033] For example: when the accessory drive system 11 adopts Figure 4 and Figure 5 When the structure is shown in (Note: Due to the complex structure and large size of components such as the low-pressure compressor 4, the high-pressure rotor 5, the low-pressure turbine 6, and the accessory transmission system 11, they are represented by boxes in the figure, and the detailed structure can refer to the existing components).

[0034] The accessory transmission system 11 includes a transmission gear train 12 and a bevel gear plate 14, which is coaxially mounted on a high-pressure compressor front journal 13 at the front of the high-pressure rotor 5, and a rear end of the bevel gear plate 14 abuts against a step surface on the high-pressure compressor front journal 13 through a second adjustment pad 15.

[0035] The transmission gear train 12 includes a transmission gear 121, a transmission train mounting seat 122, a first adjustment pad 123, an end nut 124, a bearing mounting seat 125, a transmission bearing 126, a first distance sleeve 127 and a rod bearing 128; the transmission train mounting seat 122 is fixed on the gas turbine casing 3, the bearing mounting seat 125 and the rod bearing 128 are fixed on the gas turbine casing 3, the transmission bearing 126 is installed on the inner side of the bearing mounting seat 125, the central shaft of the transmission gear 121 passes through the center of the transmission bearing 126 and the rod bearing 128, the end nut 124 is connected to the outer end of the central shaft of the transmission gear 121, the first distance sleeve 127 is sleeved outside the central shaft and abuts against the inner ring of the transmission bearing 126 and the rod bearing 128, and the tooth pattern of the transmission gear 121 is meshed with the bevel gear disk 14.

[0036] When the gas turbine is started and reaches the rated operating condition, under the reverse transmission of the bevel gear plate 14, the speed of the transmission gear 121 is often as high as 22980r / min or more, which is very easy to generate a lot of vibration, affecting the safety, stability and service life of the accessory transmission system 11 and the gas turbine during operation. In addition, due to the limited space at the high-pressure rotor 5, higher requirements are also placed on the volume and structural complexity of the accessory transmission system 11. In addition, when debugging the transmission gear train 12, it is often necessary to disassemble the front support point on the gas turbine casing 3, the low-pressure compressor 4, the high-pressure compressor, the combustion chamber, the high-pressure turbine, and the low-pressure turbine 6 to achieve inspection and debugging, and then reinstall them all, which has problems such as large workload, long cycle, and high cost.

[0037] In order to overcome the above problems existing in the high-pressure starting method, this embodiment designs a starting structure with a low-pressure rotor of a gas turbine, such as Figures 1 to 3 As shown, (Note: Due to the complex structure and large size of the low-pressure compressor 4, high-pressure rotor 5, low-pressure turbine 6, starting power system 1 and other components, they are represented by boxes in the figure, and the detailed structure can refer to the existing components).

[0038] The starting structure in this embodiment includes components such as a starting power system 1 and a starting connection assembly 2 .

[0039] The starting connection assembly 2 includes components such as a torque output shaft 21, a bearing seat 25, a front bearing 26, a rear bearing 23 and an overrunning clutch 24. The bearing seat 25 is in the shape of a circular ring with a convex middle portion. The outer middle portion of the bearing seat 25 is fixedly connected to the front end of the gas turbine casing 3, and is generally connected to the front fulcrum (cone-shaped) at the front end of the gas turbine casing 3. The front bearing 26 is connected between the front end of the bearing seat 25 and the torque output shaft 21, and the rear bearing 23 is connected between the rear end of the bearing seat 25 and the torque output shaft 21. The front end of the torque output shaft 21 is transmission-connected to the starting power system 1 (generally a spline connection), and the rear end of the torque output shaft 21 is connected to the front journal 7 of the low-pressure compressor through the overrunning clutch 24 to drive the low-pressure rotor.

[0040] Due to the larger structure and size of the low-pressure blades, the gas turbine can be started at a lower rotor speed. Generally, the gas turbine can be started when the low-pressure rotor reaches 2180r / min. At the same time, since the starting structure of this low-pressure rotor can be directly installed in front of the gas turbine, its installation space restriction is lower, and the structural complexity requirements of the starting structure are lower. During maintenance and debugging, there is no need to disassemble the gas turbine on a large scale, which reduces the difficulty of maintenance and maintenance, reduces the workload, shortens the cycle, and reduces the cost.

[0041] The front bearing 26 and the rear bearing 23 are lubricated by plastic grease, and a front oil seal assembly 28 is provided on the front side of the front bearing 26, and a rear oil seal assembly 27 is provided on the rear side of the rear bearing 23. Since the rotation speed of the starting structure of the low-pressure rotor is relatively low, the lubrication requirements can be met when only plastic grease is used at the bearing of the torque output shaft 21, and no additional lubricating oil and related lubricating oil circuits are required, which further reduces the structural complexity of the starting structure and the cost of use and maintenance.

[0042] The front oil seal assembly 28 and the rear oil seal assembly 27 both include a sealing cover 281, a cup seal 282, a retaining ring 283 and other components; the sealing cover 281 is annular and fixed to the end surface of the bearing seat 25 by bolts; the cup seal 282 is installed on the inner side of the sealing cover 281, and the cup seal 282 is sleeved outside the torque output shaft 21 to achieve sealing; the retaining ring 283 is installed on the sealing cover 281 and is used to prevent the cup seal 282 from falling off the sealing cover 281. The cup seal 282 of the front oil seal assembly 28 is in clearance fit with the sealing distance sleeve 293, and the cup seal 282 of the rear oil seal assembly 27 is in clearance fit with the torque output shaft 21, so as to ensure that the plastic grease does not leak.

[0043] An annular groove is provided on the inner side of the middle portion of the bearing seat 25 , and the annular groove is used to accommodate plastic grease and also reduces the weight of the bearing seat 25 .

[0044] A bearing spacer sleeve 22 is disposed outside the torque output shaft 21. The bearing spacer sleeve 22 is annular. The front end of the bearing spacer sleeve 22 abuts against the inner ring of the front bearing 26, and the rear end of the bearing spacer sleeve 22 abuts against the inner ring of the rear bearing 23. A step surface is disposed in the middle of the torque output shaft 21, and the rear end of the inner ring of the rear bearing 23 abuts against the step surface.

[0045] The torque output shaft 21 is tubular, and a locking assembly 29 is connected to the front end of the torque output shaft 21; a key tooth is arranged on the inner side of the front end of the torque output shaft 21 for key connection with the starting power system 1; the locking assembly 29 comprises a first slotted large nut 291, a first stop washer 292 and a sealing distance sleeve 293; the sealing distance sleeve 293 is sleeved on the outer side of the front end of the torque output shaft 21 and abuts against the inner ring of the front bearing 26; A thread is provided on the side to connect the first slotted large nut 291, so that the first slotted large nut 291 is pressed against the front end of the sealing distance sleeve 293 through the first stop gasket 292, and the protruding tongue on the inner side of the first stop gasket 292 is clamped with the groove corresponding to the torque output shaft 21 to limit the rotation of the first stop gasket 292; the stop tongue on the first stop gasket 292 can be bent into the groove on the outer side of the first slotted large nut 291 to lock the first slotted large nut 291.

[0046] A flat key 8, a second stop washer 9 and a second slotted large nut 10 are provided at the connection between the overrunning clutch 24 and the low-pressure compressor front shaft neck 7; the second slotted large nut is threadedly connected to the thread at the front end of the low-pressure compressor front shaft neck 7, and is pressed against the inner ring of the overrunning clutch 24 through the second stop washer 9, and the inner ring of the overrunning clutch 24 is key-connected to the low-pressure compressor front shaft neck 7 through the flat key 8.

[0047] In actual use, the Figures 1 to 3 However, in some experimental or test conditions, both the low-pressure rotor starting structure and the Figure 4 and Figure 5 The accessory drive system 11 shown is used to compare and study the high and low voltage starting modes.

[0048] The above embodiments are merely examples for the purpose of clarifying the description, and are not intended to limit the implementation methods; it is not necessary and impossible to list all implementation methods exhaustively. However, obvious changes or modifications derived therefrom are still within the scope of protection of the present technology.

Claims

1. A starting structure for a low-pressure rotor of a gas turbine, characterized in that: It comprises a starting power system (1) and a starting connection assembly (2); The low-pressure rotor is rotatably connected to the gas turbine casing (3), and comprises a low-pressure compressor (4) and a low-pressure turbine (6) which are connected to each other, and a low-pressure compressor front journal (7) is arranged at the front end of the low-pressure compressor (4); The starting connection assembly (2) comprises a torque output shaft (21), a bearing seat (25), a front bearing (26), a rear bearing (23) and an overrunning clutch (24); the bearing seat (25) is in the shape of a circular ring with a central portion convex outwardly, and the central outer portion of the bearing seat (25) is fixedly connected to the front end of the gas turbine casing (3); the front bearing (26) is connected between the front end of the bearing seat (25) and the torque output shaft (21), and the rear bearing (23) is connected between the rear end of the bearing seat (25) and the torque output shaft (21); the front end of the torque output shaft (21) is transmission-connected to the starting power system (1), and the rear end of the torque output shaft (21) is connected to the front journal (7) of the low-pressure compressor via the overrunning clutch (24) to drive the low-pressure rotor.

2. The starting structure for a low-pressure rotor of a gas turbine according to claim 1, characterized in that: The front bearing (26) and the rear bearing (23) are lubricated by plastic grease; a front oil sealing assembly (28) is provided on the front side of the front bearing (26), and a rear oil sealing assembly (27) is provided on the rear side of the rear bearing (23).

3. The starting structure for a low-pressure rotor of a gas turbine according to claim 2, characterized in that: The front oil seal assembly (28) and the rear oil seal assembly (27) both include a sealing cover (281), a leather cup seal (282) and a retaining ring (283); the sealing cover (281) is annular and is fixed to the end surface of the bearing seat (25) by bolts; the leather cup seal (282) is installed on the inner side of the sealing cover (281), and the leather cup seal (282) is sleeved on the outside of the torque output shaft (21) to achieve sealing; the retaining ring (283) is installed on the sealing cover (281) and is used to prevent the leather cup seal (282) from falling off the sealing cover (281).

4. The starting structure for a low-pressure rotor of a gas turbine according to claim 2, characterized in that: An annular groove is provided on the inner side of the middle portion of the bearing seat (25), and the annular groove is used to accommodate plastic grease.

5. The starting structure for a low-pressure rotor of a gas turbine according to claim 1, characterized in that: A bearing spacing sleeve (22) is arranged outside the torque output shaft (21). The bearing spacing sleeve (22) is in the shape of a circular ring. The front end of the bearing spacing sleeve (22) abuts against the inner ring of the front bearing (26), and the rear end of the bearing spacing sleeve (22) abuts against the inner ring of the rear bearing (23).

6. The starting structure for a low-pressure rotor of a gas turbine according to claim 5, characterized in that: A step surface is provided in the middle of the torque output shaft (21), and the rear end of the inner ring of the rear bearing (23) abuts against the step surface.

7. The starting structure for a low-pressure rotor of a gas turbine according to claim 1, characterized in that: The torque output shaft (21) is tubular, and a locking assembly (29) is connected to the front end of the torque output shaft (21); a key tooth is provided on the inner side of the front end of the torque output shaft (21) for key connection to the starting power system (1); the locking assembly (29) comprises a first slotted large nut (291), a first stop washer (292) and a sealing distance sleeve (293); the sealing distance sleeve (293) is sleeved on the outer side of the front end of the torque output shaft (21) and abuts against the inner ring of the front bearing (26); A thread is provided on the outer side of the front end to connect with the first slotted large nut (291), so that the first slotted large nut (291) is pressed against the front end of the sealing distance sleeve (293) through the first stop washer (292), and the protruding tongue on the inner side of the first stop washer (292) is clamped with the groove corresponding to the torque output shaft (21) to limit the rotation of the first stop washer (292); the stop tongue on the first stop washer (292) can be bent into the groove on the outer side of the first slotted large nut (291) to lock the first slotted large nut (291).

8. The starting structure for a low-pressure rotor of a gas turbine according to claim 1, characterized in that: A flat key (8), a second stop washer (9) and a second slotted large nut (10) are provided at the connection between the overrunning clutch (24) and the low-pressure compressor front shaft neck (7); the second slotted large nut (10) is threadedly connected to the thread at the front end of the low-pressure compressor front shaft neck (7) and is pressed against the inner ring of the overrunning clutch (24) through the second stop washer (9); the inner ring of the overrunning clutch (24) is key-connected to the low-pressure compressor front shaft neck (7) through the flat key (8).

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