CN111706403A

CN111706403A - Steam inlet flow guide structure of double-flow intermediate pressure cylinder

Info

Publication number: CN111706403A
Application number: CN202010596618.4A
Authority: CN
Inventors: 倪云泽; 吴仕芳; 黄庆华; 华文祥
Original assignee: Shanghai Electric Power Generation Equipment Co Ltd
Current assignee: Shanghai Electric Power Generation Equipment Co Ltd
Priority date: 2020-06-28
Filing date: 2020-06-28
Publication date: 2020-09-25
Anticipated expiration: 2040-06-28
Also published as: CN111706403B

Abstract

The invention provides a steam inlet flow guide structure of a double-flow intermediate pressure cylinder, which comprises: the first guide ring is positioned at the communication part of the steam inlet cavity and the first flow channel and comprises a first mounting outer ring fixed on the inner cylinder body and a first guide inner ring sleeved on the rotor in a clearance manner; the second guide ring is positioned at the communication part of the steam inlet cavity and the second flow channel and comprises a second mounting outer ring fixed on the inner cylinder body and a second guide inner ring sleeved on the rotor in a clearance manner; the first guide ring and the second guide ring are coaxially clamped to prevent steam from blowing to the rotor in the radial direction, and the steam in the steam inlet chamber is divided into first steam flow entering the first flow channel and second steam flow entering the second flow channel under the blocking and guiding effects of the first guide ring and the second guide ring. The invention can effectively avoid steam from directly impacting the rotor and effectively control the steam leakage amount, so that the energy conversion rate of the first stationary blade and the second stationary blade matched with the steam inlet flow guide structure is higher.

Description

Steam inlet flow guide structure of double-flow intermediate pressure cylinder

Technical Field

The invention relates to the technical field of steam turbine flow guiding, in particular to a steam inlet flow guiding structure of a double-flow intermediate pressure cylinder.

Background

The steam turbine rotor is a high-speed rotating component which is in a high-temperature and high-pressure steam environment and bears a plurality of complex and changeable external conditions such as temperature stress, steam pressure load, centrifugal force load, power generation output torque and the like. In order to ensure the safe operation of the steam turbine rotor in the service period, the strength performance test of the rotor needs to be examined through key points such as reasonable structural design, material selection, working condition environment setting and the like in the design stage.

The ultra-supercritical steam turbine has high energy conversion efficiency and convenient operation and maintenance, and plays a significant role in the field of power generation equipment. The medium-pressure steam inlet temperature of the ultra-supercritical steam turbine is generally 600-620 ℃, if steam with high temperature directly impacts the surface of the medium-pressure rotor, the influence on the lasting operation strength of the rotor and the creep property of materials is very large, and potential safety hazards are easily generated after the steam is operated for a long time. Generally, there are two existing solutions to this problem, briefly described as follows:

the first existing method: the rotor material is upgraded. In order to relieve the high-temperature creep condition of the durable operation of the medium-pressure rotor, the medium-pressure rotor is designed and produced by adopting a material with the grade of 630 ℃. After the material is upgraded, the reheated steam at the temperature of 620 ℃ cannot damage the medium-pressure rotor destructively, and potential safety hazards are eliminated. However, after the material of the rotor is upgraded, the incomplete condition of the production and processing technology prolongs the delivery time of the rotor, so that the material cost of the rotor is increased; at the same time, new rotor material will also affect the clearance level of thermal expansion of the intermediate pressure cylinder module, resulting in an increase in the amount of leakage steam between the blade stages.

The second method comprises the following steps: and a necessary design means is adopted to avoid that medium-pressure steam enters to directly impact the surface of the rotor. The scheme commonly adopted in the industry is as follows: the first stage stationary blade is made into a structure with a flow guiding function. The steam firstly passes through the stationary blade to carry out energy conversion, and the steam at the outlet of the stationary blade flows to the surface of the rotor, so that the working state of the medium-pressure rotor can be effectively improved. According to design experience, the vane outlet steam temperature can typically be reduced by about 20 ℃ to 23 ℃. Meanwhile, the stationary blade can be provided with jet holes, and the surface of the medium-pressure rotor can be cooled by about 10-15 ℃, so that the surface temperature of the medium-pressure rotor is effectively reduced from two aspects. The stationary blade with the flow guide function has the following defects: the structure is too complex, the enthalpy drop task is borne, the matching requirement of the structural design is met, and the requirements on the structural design, the processing technology and the processing precision are higher. The processing mode of the forging machine is that the ring is continuously worked for a long time by a high-precision machine tool on the basis of forging the ring in a whole circle, the manufacturing period is long, and the manufacturing cost is high. In addition, in order to ensure the processing of the stator blade with the flow guiding function, the molded line design optimization space of the blade is small, so that the energy conversion efficiency of the stage is lower than that of the conventional blade stage.

Disclosure of Invention

In view of the above-mentioned drawbacks of the prior art, an object of the present invention is to provide a steam inlet flow guiding structure of a dual-flow intermediate pressure cylinder, which can make steam contact with a rotor after flowing through a first stationary blade and a second stationary blade, respectively, without changing the rotor material, so as to effectively avoid the steam from directly impacting the rotor, and effectively control the steam leakage amount, so that the energy conversion rate of the steam inlet flow guiding structure matched with the first stationary blade and the second stationary blade is relatively high.

In order to solve the technical problem, the present invention provides a steam inlet flow guiding structure of a dual-flow intermediate pressure cylinder, where the dual-flow intermediate pressure cylinder includes an outer cylinder body, an inner cylinder body fixedly disposed in the outer cylinder body, and a rotor rotatably disposed in the inner cylinder body, one end of the rotor is a motor end, the other end of the rotor is a valve adjusting end, two flow channels which are symmetrically distributed and have opposite flow directions are formed in a space defined by the inner cylinder body and the rotor together, where the flow channel flowing to the motor end is a first flow channel, and the flow channel flowing to the valve adjusting end is a second flow channel, the steam inlet flow guiding structure includes:

the first guide ring is positioned at the communication part of the steam inlet cavity and the first runner, the first guide ring comprises a first mounting outer ring fixed on the inner cylinder body and a first guide inner ring sleeved on the rotor in a clearance manner, the first guide inner ring is fixedly connected with the first mounting outer ring through a plurality of first supporting pieces, and the central axis of the first guide inner ring is superposed with the rotation axis of the rotor;

the second guide ring is positioned at the communication position of the steam inlet cavity and the second flow channel, the second guide ring comprises a second mounting outer ring fixed on the inner cylinder body and a second guide inner ring sleeved on the rotor in a clearance manner, the second guide inner ring is fixedly connected with the second mounting outer ring through a plurality of second supporting pieces, and the central axis of the second guide inner ring is coincided with the rotation axis of the rotor.

Preferably, a first stationary blade connected with the inner cylinder body is arranged at the steam inlet of the first flow passage, a second stationary blade connected with the inner cylinder body is arranged at the steam inlet of the second flow passage, a steam inlet chamber is arranged in the middle of the inner cylinder body, and a steam outlet of the steam inlet chamber faces inwards in the radial direction and is respectively communicated with the steam inlet of the first flow passage and the steam inlet of the second flow passage; the port of the first flow guide inner ring, which faces the valve adjusting end, is provided with a first steam seal convex edge, and the port of the first flow guide inner ring, which faces the motor end, is provided with a first hook edge in clamping fit with the shroud band of the first stationary blade; the port of the second flow guide inner ring facing the motor end is provided with a second steam seal convex edge in clamping fit with the first steam seal convex edge, and the port of the second flow guide inner ring facing the valve adjusting end is provided with a second hook edge in clamping fit with the shroud band of the second stationary blade; the first guide ring and the second guide ring are coaxially clamped to prevent steam from radially blowing to the rotor, and the steam in the steam inlet chamber is divided into first steam flow entering the first flow channel and second steam flow entering the second flow channel under the blocking and guiding effects of the first guide inner ring and the second guide inner ring.

Preferably, all the first supporting pieces circumferentially and uniformly extend in the radial direction by taking the circle center of the first flow guide inner ring as the circle center.

Preferably, all the second supporting pieces circumferentially and uniformly distributed and radially extend by taking the circle center of the second flow guide inner ring as the circle center.

Preferably, the first mounting outer ring is composed of two first mounting semicircular rings, and two circumferential ends of each first mounting semicircular ring are provided with first flange structures connected with the inner cylinder body; the first flow guide inner ring is composed of two first flow guide semicircular rings, and each first flow guide semicircular ring is connected with the corresponding first installation semicircular ring through a first supporting piece.

Preferably, the second mounting outer ring is composed of two second mounting semicircular rings, and two circumferential ends of each second mounting semicircular ring are provided with second flange structures connected with the inner cylinder body; the second flow guide inner ring is composed of two second flow guide semicircular rings, and each second flow guide semicircular ring is connected with the corresponding second installation semicircular ring through a second supporting piece.

Preferably, the inner peripheral wall of the inner cylinder body is provided with a first positioning groove and a second positioning groove, the first installation outer ring is provided with a first positioning key, the first positioning key is embedded in the first positioning groove, the second installation outer ring is provided with a second positioning key, and the second positioning key is embedded in the second positioning groove.

Preferably, the number of the first positioning keys is two, wherein one first positioning key is arranged at the top of the first mounting outer ring, and the other first positioning key is arranged at the bottom of the first mounting outer ring.

Preferably, the number of the second positioning keys is two, wherein one second positioning key is arranged at the top of the second mounting outer ring, and the other second positioning key is arranged at the bottom of the second mounting outer ring.

Preferably, the first steam seal convex edge is overlapped on one side, back to the rotor, of the second steam seal convex edge, and the peripheral wall of the first flow guide inner ring is aligned and connected with the peripheral wall of the second flow guide inner ring.

As described above, the steam inlet flow guide structure of the double-flow intermediate pressure cylinder of the invention has the following beneficial effects: in the invention, a first installation outer ring of a first guide ring is assembled on an inner cylinder body and is positioned and supported by a first support piece, the first guide inner ring is arranged near a steam outlet of a steam inlet chamber, blocks steam from blowing to a rotor in the radial direction and guides the steam to a first stationary blade; the structure and the function of the second guide ring are the same as those of the first guide ring. The steam passing through the first stationary blade generates enthalpy drop, the temperature of the steam is reduced, the rotor cannot be damaged, meanwhile, the pressure difference at the downstream of the first stationary blade can also ensure the flow of the steam, and the heat on the surface of the rotor is taken away in time. More importantly, the first vane may be a vane of a conventional pressure stage, the profile design and manufacturing process of which is not adversely affected. Therefore, the steam inlet flow guide structure can enable steam to respectively flow through the first stationary blade and the second stationary blade and then contact the rotor under the condition that the rotor material is not changed, so that the steam is effectively prevented from directly impacting the rotor, and the steam leakage amount is effectively controlled, so that the energy conversion rate of the first stationary blade and the second stationary blade matched with the steam inlet flow guide structure is higher.

Drawings

FIG. 1 is a schematic view of the steam admission flow guiding structure of the double flow intermediate pressure cylinder of the present invention;

FIG. 2 is an enlarged view of portion A of FIG. 1;

FIG. 3 is an assembled cross-sectional view of the first mounting outer ring, the first detent key and the first detent groove;

FIG. 4 is an assembled cross-sectional view of a second mounting outer ring, a second detent key and a second detent;

FIG. 5 is a schematic view of a first mounting semi-ring and a first flow directing semi-ring;

FIG. 6 is a schematic view of a second mounting semi-ring and a second flow directing semi-ring;

FIG. 7 shows an assembled cross-sectional view of the first flange structure and the inner cylinder block;

fig. 8 shows an assembled sectional view of the second flange structure and the inner cylinder block.

Description of the element reference numerals

1 outer cylinder body

2 inner cylinder body

21 air inlet chamber

211 steam outlet

22 first positioning groove

23 second positioning groove

3 rotor

4 first flow channel

41 first vane

5 second flow channel

51 second stationary blade

6 first flow guide ring

61 first installation outer ring

611 first mounting semi-circle ring

612 first flange structure

62 first flow guiding inner ring

621 first vapor seal convex edge

622 first hook edge

623 first diversion semicircular ring

63 first support

64 first positioning key

7 second flow guide ring

71 second mounting outer ring

711 second mounting semi-circle ring

712 second flange structure

72 second flow guiding inner ring

721 second vapor seal convex edge

722 second hook edge

723 second guide semicircular ring

73 second support

74 second positioning key

Detailed Description

The following description of the embodiments of the present invention is provided for illustrative purposes, and other advantages and effects of the present invention will become apparent to those skilled in the art from the present disclosure.

It should be understood that the structures, ratios, sizes, and the like shown in the drawings are only used for matching the disclosure of the present disclosure, and are not used for limiting the conditions that the present disclosure can be implemented, so that the present disclosure is not limited to the technical essence, and any structural modifications, ratio changes, or size adjustments should still fall within the scope of the present disclosure without affecting the efficacy and the achievable purpose of the present disclosure. In addition, the terms "upper", "lower", "left", "right", "middle" and "one" used in the present specification are for clarity of description, and are not intended to limit the scope of the present invention, and the relative relationship between the terms and the terms is not to be construed as a scope of the present invention.

As shown in fig. 1 and 2, the dual flow intermediate pressure cylinder includes an outer cylinder 1, an inner cylinder 2 fixedly disposed in the outer cylinder 1, and a rotor 3 rotatably disposed in the inner cylinder 2, one end of the rotor 3 is a motor end, the other end of the rotor 3 is a valve adjusting end, two flow channels are symmetrically distributed and oppositely flow in a space defined by the inner cylinder 2 and the rotor 3, wherein the flow channel flowing to the motor end is a first flow channel 4, the flow channel flowing to the valve adjusting end is a second flow channel 5, a first stationary blade 41 (the first stationary blade 41 is a first-stage stationary blade) connected to the inner cylinder 2 is disposed at a steam inlet of the first flow channel 4, a second stationary blade 51 (the second stationary blade 51 is a first-stage stationary blade) connected to the inner cylinder 2 is disposed at a steam inlet of the second flow channel 5, a steam inlet chamber 21 is disposed at a middle portion of the inner cylinder 2, steam outlets 211 of the steam inlet chamber 21 are radially inward and are respectively connected to the steam inlets of the first flow channel 4, The steam inlets of the second flow passages 5 are communicated.

The invention provides a steam inlet flow guide structure of a double-flow intermediate pressure cylinder, which comprises:

the first guide ring 6 is positioned at the communication part of the steam inlet chamber 21 and the first flow channel 4, the first guide ring 6 comprises a first mounting outer ring 61 fixed on the inner cylinder body 2 and a first guide inner ring 62 sleeved on the rotor 3 in a clearance manner, the first guide inner ring 62 is fixedly connected with the first mounting outer ring 61 through a plurality of first supporting pieces 63, and the central axis of the first guide inner ring 62 is coincided with the rotation axis of the rotor 3;

the second guide ring 7 is positioned at the communication position of the steam inlet chamber 21 and the second flow channel 5, the second guide ring 7 comprises a second mounting outer ring 71 fixed on the inner cylinder body 2 and a second guide inner ring 72 sleeved on the rotor 3 in a clearance manner, the second guide inner ring 72 is fixedly connected with the second mounting outer ring 71 through a plurality of second supporting pieces 73, and the central axis of the second guide inner ring 72 is coincided with the rotation axis of the rotor 3.

In the present invention, the first mounting outer ring 61 of the first deflector ring 6 is fitted on the inner cylinder 2 and positions, supports, by the first support 63, the first deflector inner ring 62 is arranged in the vicinity of the steam outlet 211 of the steam inlet chamber 21, blocks the steam from blowing radially toward the rotor 3, and guides the steam toward the first stationary blade 41; the second guide ring 7 has the same structure and function as the first guide ring 6, and is not described in detail here. The steam passing through the first stationary blade 41 generates enthalpy drop, the temperature of the steam is reduced, the rotor 3 is not damaged, and meanwhile, the pressure difference at the downstream of the first stationary blade 41 can ensure the flow of the steam and take away the heat on the surface of the rotor 3 in time. More importantly, the first vanes 41 may be conventional pressure stage vanes, the profile design and manufacturing process of which are not adversely affected.

Therefore, the steam inlet flow guide structure of the double-flow intermediate pressure cylinder has the following technical effects:

1) without changing the material of the rotor 3, the profile design and the manufacturing process of the first vane 41 and the second vane 51 are not adversely affected;

2) the first guide ring 6 and the second guide ring 7 of the steam inlet guide structure are simple in structure and easy to process and assemble;

3) the first guide ring 6 and the second guide ring 7 are coaxially clamped, so that high-temperature steam is effectively prevented from directly impacting the rotor 3, and the steam leakage amount is effectively controlled;

4) the energy conversion rate of the first stationary blade 41 and the second stationary blade 51 matched with the steam inlet flow guide structure is higher than that of the stationary blade with the flow guide structure in the prior art.

A first stationary blade 41 connected with the inner cylinder body 2 is arranged at the steam inlet of the first flow passage 4, a second stationary blade 51 connected with the inner cylinder body 2 is arranged at the steam inlet of the second flow passage 5, a steam inlet chamber 21 is arranged at the middle of the inner cylinder body 2, and a steam outlet 211 of the steam inlet chamber 21 faces radially inwards and is respectively communicated with the steam inlet of the first flow passage 4 and the steam inlet of the second flow passage 5; the port of the first flow guiding inner ring 62 facing the valve adjusting end is provided with a first steam sealing convex edge 621, and the port of the first flow guiding inner ring 62 facing the motor end is provided with a first hook edge 622 in clamping fit with the shroud of the first stationary blade 41; the port of the second flow guide inner ring 72 facing the motor end is provided with a second steam seal convex edge 721 in clamping fit with the first steam seal convex edge 621, and the port of the second flow guide inner ring 72 facing the valve adjusting end is provided with a second hook edge 722 in clamping fit with the shroud of the second stationary blade 51; the first guide ring 6 and the second guide ring 7 are coaxially clamped to prevent steam from blowing to the rotor 3 in the radial direction, and the steam in the steam inlet chamber 21 is divided into a first steam flow entering the first flow passage 4 and a second steam flow entering the second flow passage 5 under the blocking and guiding effects of the first guide inner ring 62 and the second guide inner ring 72. The first steam seal convex edge 621 of the first flow guide inner ring 62 and the second steam seal convex edge 721 of the second flow guide inner ring 72 are in clamping fit, so that a clamping position of the first flow guide inner ring 62 and the second flow guide inner ring 72 forms a labyrinth steam seal structure, and steam is prevented from blowing to the rotor 3 from the clamping position of the first flow guide inner ring 62 and the second flow guide inner ring 72. In addition, the first hook edge 622 of the first flow guiding inner ring 62 is in snap fit with the shroud of the first stationary blade 41, so that the steam flows through the first stationary blade 41 and then is blown to the rotor. Similarly, the second hook edge 722 of the second guide inner ring 72 is in snap fit with the shroud of the second stationary blade 51, and the technical effect of the arrangement is the same as that of the first hook edge 622, which is not described herein again.

In order to improve the stability of the first flow guiding inner ring 62, all the first supporting members 63 are circumferentially and uniformly distributed and radially extend around the center of the first flow guiding inner ring 62.

In order to improve the stability of the second flow guiding inner ring 72, all the second supporting members 73 are circumferentially and uniformly distributed and radially extend around the center of the second flow guiding inner ring 72.

For the convenience of dismouting, above-mentioned first water conservancy diversion ring 6 and second water conservancy diversion ring 7 all adopt half-and-half structure from top to bottom:

as shown in fig. 5 and 7, the first mounting outer ring 61 is formed by two first mounting semicircular rings 611, and both ends of the circumferential direction of each first mounting semicircular ring 611 are provided with first flange structures 612 connected with the inner cylinder 2; the first flow guiding inner ring 62 is formed by two first flow guiding semi-circular rings 623, and each first flow guiding semi-circular ring 623 is connected with the corresponding first mounting semi-circular ring 611 through a first supporting member 63. Specifically, the first flange structure 612 is detachably connected to the inner cylinder 2 by screws.

As shown in fig. 6 and 8, the second mounting outer ring 71 is composed of two second mounting semicircular rings 711, and both ends of the circumferential direction of each second mounting semicircular ring 711 are provided with second flange structures 712 connected with the inner cylinder 2; the second flow guiding inner ring 72 is formed by two second flow guiding semi-circular rings 723, and each second flow guiding semi-circular ring 723 is connected with a corresponding second mounting semi-circular ring 711 through a second support 73. Specifically, the second flange structure 712 is detachably connected to the inner cylinder 2 by screws.

As shown in fig. 3 and 4, in order to facilitate positioning and installation of the first deflector ring 6 and the second deflector ring 7, the inner circumferential wall of the inner cylinder 2 is provided with a first positioning groove 22 and a second positioning groove 23, the first installation outer ring 61 is provided with a first positioning key 64, the first positioning key 64 is embedded in the first positioning groove 22, the second installation outer ring 71 is provided with a second positioning key 74, and the second positioning key 74 is embedded in the second positioning groove 23. Further, the number of the first positioning keys 64 is two, wherein one first positioning key 64 is arranged on the top of the first mounting outer ring 61, and the other first positioning key 64 is arranged on the bottom of the first mounting outer ring 61. Similarly, the number of the second positioning keys 74 is two, wherein one second positioning key 74 is arranged on the top of the second mounting outer ring 71, and the other second positioning key 74 is arranged on the bottom of the second mounting outer ring 71.

As a fastening method of the first and second flow guide inner rings 62 and 72: the first steam seal convex edge 621 is overlapped on one side of the second steam seal convex edge 721 back to the rotor 3, and the peripheral wall of the first flow guide inner ring 62 is aligned and connected with the peripheral wall of the second flow guide inner ring 72.

In summary, in the steam inlet flow guide structure of the double-flow intermediate pressure cylinder of the present invention, under the condition that the material of the rotor is not changed, the steam can contact the rotor after flowing through the first stationary blade and the second stationary blade respectively, so as to effectively avoid the steam from directly impacting the rotor, and effectively control the steam leakage amount, so that the energy conversion rate of the first stationary blade and the second stationary blade in combination with the steam inlet flow guide structure is relatively high. Therefore, the invention effectively overcomes various defects in the prior art and has high industrial utilization value.

The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.

Claims

1. The utility model provides an admission water conservancy diversion structure of double-flow intermediate pressure cylinder, double-flow intermediate pressure cylinder includes outer cylinder body (1), fixed inner cylinder body (2) that set up in outer cylinder body (1) and rotates rotor (3) that set up in inner cylinder body (2), the one end of rotor (3) is the motor end, the other end of rotor (3) is for transferring the valve end, the space that is defined jointly by inner cylinder body (2) and rotor (3) forms two runners that symmetric distribution and flow direction are opposite, wherein the runner that flows to the motor end is first runner (4), the runner that the valve end was transferred to the flow direction is second runner (5), a serial communication port, admission water conservancy diversion structure includes:

the first guide ring (6) is positioned at the communication position of the steam inlet chamber (21) and the first flow channel (4), the first guide ring (6) comprises a first mounting outer ring (61) fixed on the inner cylinder body (2) and a first guide inner ring (62) sleeved on the rotor (3) in a clearance mode, the first guide inner ring (62) is fixedly connected with the first mounting outer ring (61) through a plurality of first supporting pieces (63), and the central axis of the first guide inner ring (62) is overlapped with the rotating axis of the rotor (3);

the second guide ring (7) is positioned at the communication position of the steam inlet chamber (21) and the second flow channel (5), the second guide ring (7) comprises a second mounting outer ring (71) fixed on the inner cylinder body (2) and a second guide inner ring (72) sleeved on the rotor (3) in a clearance mode, the second guide inner ring (72) is fixedly connected with the second mounting outer ring (71) through a plurality of second supporting pieces (73), and the central axis of the second guide inner ring (72) is coincident with the rotating axis of the rotor (3).

2. The steam inlet flow guide structure of the double-flow intermediate pressure cylinder as claimed in claim 1, wherein: a first stationary blade (41) connected with the inner cylinder body (2) is arranged at the steam inlet of the first flow channel (4), a second stationary blade (51) connected with the inner cylinder body (2) is arranged at the steam inlet of the second flow channel (5), a steam inlet chamber (21) is arranged in the middle of the inner cylinder body (2), and a steam outlet (211) of the steam inlet chamber (21) faces inwards in the radial direction and is respectively communicated with the steam inlet of the first flow channel (4) and the steam inlet of the second flow channel (5); the port of the first flow guide inner ring (62) facing the valve adjusting end is provided with a first steam seal convex edge (621), and the port of the first flow guide inner ring (62) facing the motor end is provided with a first hook edge (622) in clamping fit with the shroud of the first stationary blade (41); the port of the second flow guide inner ring (72) facing the motor end is provided with a second steam seal convex edge (721) in clamping fit with the first steam seal convex edge (621), and the port of the second flow guide inner ring (72) facing the valve adjusting end is provided with a second hook edge (722) in clamping fit with the shroud of the second stationary blade (51); the first guide ring (6) and the second guide ring (7) are coaxially clamped to prevent steam from radially blowing to the rotor (3), and the steam in the steam inlet chamber (21) is divided into first steam flow entering the first flow channel (4) and second steam flow entering the second flow channel (5) under the blocking and guiding effects of the first guide inner ring (62) and the second guide inner ring (72).

3. The steam inlet flow guide structure of the double-flow intermediate pressure cylinder as claimed in claim 1, wherein: all the first supporting pieces (63) circumferentially and uniformly distributed and radially extend by taking the circle center of the first flow guide inner ring (62) as the circle center.

4. The steam inlet flow guide structure of the double-flow intermediate pressure cylinder as claimed in claim 1, wherein: all the second supporting pieces (73) circumferentially and uniformly distributed and radially extend by taking the circle center of the second flow guide inner ring (72) as the circle center.

5. The steam inlet flow guide structure of the double-flow intermediate pressure cylinder as claimed in claim 1, wherein: the first mounting outer ring (61) is composed of two first mounting semi-circular rings (611), and two circumferential ends of each first mounting semi-circular ring (611) are provided with first flange structures (612) connected with the inner cylinder body (2); the first flow guide inner ring (62) is composed of two first flow guide semi-circular rings (623), and each first flow guide semi-circular ring (623) is connected with the corresponding first installation semi-circular ring (611) through a first support piece (63).

6. The steam inlet flow guide structure of the double-flow intermediate pressure cylinder as claimed in claim 1, wherein: the second mounting outer ring (71) is composed of two second mounting semicircular rings (711), and two circumferential ends of each second mounting semicircular ring (711) are provided with second flange structures (712) connected with the inner cylinder body (2); the second flow guide inner ring (72) is composed of two second flow guide semi-circular rings (723), and each second flow guide semi-circular ring (723) is connected with a corresponding second mounting semi-circular ring (711) through a second support member (73).

7. The steam inlet flow guide structure of the double-flow intermediate pressure cylinder as claimed in claim 1, wherein: be equipped with first constant head tank (22) and second constant head tank (23) on the internal perisporium of interior cylinder body (2), be equipped with first navigation key (64) on first installation outer loop (61), first navigation key (64) inlay establishes in first constant head tank (22), be equipped with second navigation key (74) on second installation outer loop (71), second navigation key (74) inlay establishes in second constant head tank (23).

8. The steam inlet flow guide structure of the double flow intermediate pressure cylinder as claimed in claim 7, wherein: the number of the first positioning keys (64) is two, wherein one first positioning key (64) is arranged at the top of the first mounting outer ring (61), and the other first positioning key (64) is arranged at the bottom of the first mounting outer ring (61).

9. The steam inlet flow guide structure of the double flow intermediate pressure cylinder as claimed in claim 7, wherein: the number of the second positioning keys (74) is two, wherein one second positioning key (74) is arranged at the top of the second mounting outer ring (71), and the other second positioning key (74) is arranged at the bottom of the second mounting outer ring (71).

10. The steam inlet flow guide structure of the double-flow intermediate pressure cylinder as claimed in claim 1, wherein: the first steam seal convex edge (621) is overlapped on one side, back to the rotor (3), of the second steam seal convex edge (721), and the peripheral wall of the first flow guide inner ring (62) is aligned and connected with the peripheral wall of the second flow guide inner ring (72).