Internal dehumidification structure of steam turbine

Abstract

The invention discloses an internal dehumidification structure of a steam turbine, which belongs to the technical field of steam turbines, and comprises a steam seal body which is coaxially arranged on a rotor and is in rotary sealing fit with the outer peripheral wall of the rotor, the outer end part of the steam seal body is fixedly arranged on the inner side of a cylinder body, and the steam seal body is provided with a water gathering groove which is coaxially arranged with the steam seal body; a drainage pipeline which radially penetrates through the steam seal body is arranged at one position of the water gathering tank; the multiple dehumidification blades are annularly connected to the first wall with the axis of the rotor as the center, and each dehumidification blade is provided with a flow guide wall; when the rotor rotates, wet steam in the cylinder body enters the water gathering groove through the flow guide walls on the multiple dehumidification blades and is discharged through the drainage pipeline. The dehumidification structure is integrated on the steam sealing structure, the position where a sealing structure needs to be arranged originally is utilized, a dehumidification component does not need to be additionally arranged in the cavity, and the space of the cavity is prevented from being occupied.

Description

Technical Field

[0001] The present invention relates to the technical field of steam turbines, and in particular to a dehumidification structure inside a steam turbine. Background Art

[0002] In modern power industry, as a key device for converting steam thermal energy into mechanical energy, the operating efficiency and reliability of a steam turbine are crucial for the entire power generation system. However, there is a problem of wet steam during the operation of the steam turbine.

[0003] The forms of wet steam existing in the steam turbine are complex and diverse. It contains extremely fine water droplets generated by spontaneous condensation, namely primary water droplets. These water droplets are tiny in size and have excellent followability with the main steam flow, which makes it extremely difficult for them to separate from the main flow during the steam flow process. Another type is the large water droplets formed by the rupture of the water film on the blade surface, that is, secondary water droplets. Their size ranges from about 10um to hundreds of micrometers. Compared with primary water droplets, the separation difficulty of secondary water droplets is relatively small.

[0004] At present, the negative impacts brought by wet steam inside the steam turbine are extremely significant. On the one hand, the water droplets in the wet steam will cause the efficiency of the steam turbine to decrease. On the other hand, wet steam is an important cause of blade erosion. Whether it is primary water droplets or secondary water droplets, under high-speed impact, they will have an erosive effect on the surface of the steam turbine blades.

[0005] To solve the problem of wet steam, in the prior art, a dehumidification structure is mostly arranged inside the steam turbine cylinder chamber. However, this traditional design has many drawbacks. The internal space of the cylinder chamber is limited and the layout is compact. The additional dehumidification components not only occupy a large amount of space, but also interfere with the normal flow path of the steam in the chamber, having an adverse impact on the flow efficiency. At the same time, the setting of the dehumidification structure also restricts the reasonable arrangement of the blades, making the design and installation of the blades unable to reach the optimal state, further affecting the overall performance of the steam turbine. Summary of the Invention

[0006] An embodiment of the present invention provides a dehumidification structure inside a steam turbine to solve the problems in the prior art.

[0007] The embodiments of the present invention adopt the following technical solutions: A dehumidification structure inside a steam turbine is arranged between the steam turbine cylinder body and the steam turbine rotor. A first wall is formed on the outer peripheral surface of the rotor. The dehumidification structure further includes: A steam seal body coaxially arranged on the rotor and in rotational sealing cooperation with the outer peripheral wall of the rotor. The outer end of the steam seal body is fixedly installed on the inner side of the cylinder body. The steam seal body has a water collecting groove coaxially arranged with it, and a drain pipeline radially penetrating the steam seal body is provided at one place of the water collecting groove; Dehumidification blades, several of which are configured and annularly connected to the first wall with the rotor axis as the center. A guiding wall is provided on each dehumidification blade; When the rotor rotates, the wet steam inside the cylinder body enters the water collecting groove through the guiding walls on several dehumidification blades and is discharged through the drain pipeline.

[0008] Preferably, two adjacent surfaces of the dehumidification blade coincide with or are attached to the first wall and the outer peripheral wall of the rotor respectively.

[0009] Preferably, the dehumidification blade is integrally formed with the rotor.

[0010] Preferably, the guiding wall is composed of an inclined working surface and a guiding inclined surface located on the adjacent side of the working surface and facing the first wall; Among them, when the rotor rotates, part of the wet steam impacts on the working surface and enters the water collecting groove along the working surface; When the rotor rotates, part of the wet steam parallel or tending to be parallel to the rotor axis impacts on the guiding inclined surface and enters the water collecting groove along the guiding inclined surface.

[0011] Preferably, the outer end of the dehumidification blade is set as a cylindrical surface coaxial and of the same diameter as the outer diameter part of the first wall of the rotor. This cylindrical surface is an adjacent surface to the working surface and is also an adjacent surface to the guiding inclined surface.

[0012] Preferably, the dehumidification blade further has a pressure surface on the opposite side of the working surface, and this pressure surface is perpendicular to the outer peripheral wall of the rotor.

[0013] Preferably, the guiding inclined surface is inclined along the rotor axis and the inclination angle is 105° - 115°.

[0014] Preferably, an annular pressing plate is coaxially installed on the steam seal body. The inner end of the annular pressing plate is provided with two inclined and adjacent chamfered surfaces. The connection part of the two chamfered surfaces is located outside the opening of the water collecting groove. Among them, the chamfered surface close to the water collecting groove is inclined and transitions into the inside of the water collecting groove.

[0015] Preferably, an annular guiding surface coaxial with the steam seal body is also formed on the steam seal body. This annular guiding surface extends obliquely outward from the inner end of the steam seal body; The wet steam impacts on the annular guiding surface along the guiding wall and impacts on the chamfered surface close to the water collecting groove after passing through the annular guiding surface.

[0016] Preferably, the included angle between the annular flow guiding surface and its axis is set to 66°-68°.

[0017] Preferably, an inner water storage channel coaxial with and recessed inward is formed inside the water collecting tank and near the rotor, and the drain pipeline is located at the lowest position of the water collecting tank.

[0018] Preferably, the diameter of the part of the rotor at the dehumidifying blade is 426 mm, the height of the dehumidifying blade along the radial direction of the rotor is 53 mm, the span between two adjacent dehumidifying blades is 23°, and the cylindrical surface span of each dehumidifying blade is 2°.

[0019] The above at least one technical solution adopted in the embodiment of the present invention can achieve the following beneficial effects: First, most of the existing dehumidification structures are designed inside the cylinder chamber, which will occupy the chamber space and have an adverse impact on the flow-through efficiency and blade arrangement. In this application, the dehumidification structure is integrated into the steam seal structure, making use of the position where a sealing structure originally needs to be set (because some chambers of the steam turbine need to be provided with steam extraction ports, and the steam seal body is installed between the rotor and the cylinder to separate the two chambers and achieve sealing). There is no need to additionally arrange dehumidification components inside the chamber, avoiding occupying the chamber space, being beneficial to improving the utilization rate of the internal space of the steam turbine, optimizing the flow-through path, improving the flow-through efficiency, and also being more convenient for the reasonable arrangement of blades. In addition, with the help of the steam seal body, both the sealing function between different chambers of the steam turbine and the dehumidification function are realized.

[0020] Second, through the flow guiding wall of the dehumidifying blade, the wet steam can be effectively guided to the water collecting tank, and the dehumidification efficiency is improved by using the power generated by the rotation of the rotor and the steam flow characteristics. The moisture in the wet steam is discharged in time, reducing the erosion of components such as the blades of the steam turbine by moisture, and helping to extend the service life of the steam turbine. Description of the Drawings

[0021] The drawings described herein are used to provide a further understanding of the present invention, form a part of the present invention, and the schematic embodiments of the present invention and their descriptions are used to explain the present invention, and do not constitute an improper limitation to the present invention. In the drawings: Figure 1 It is a three-dimensional structure diagram of the rotor and the dehumidification structure of the present invention; Figure 2 It is a plane cross-sectional view of the rotor and the dehumidification structure of the present invention; Figure 3 It is a three-dimensional cross-sectional view of the rotor and the dehumidification structure of the present invention; Figure 4 It is a three-dimensional view of the rotor and the dehumidifying blade of the present invention; Figure 5 It is an exploded view of the rotor and the dehumidification structure of the present invention; Reference Signs 1 - Rotor; 2 - First wall; 3 - Steam seal body; 31 - Water collecting groove; 32 - Drainage pipeline; 33 - Annular guiding surface; 34 - Water storage channel; 4 - Dehumidification blade; 41 - Working surface; 42 - Guiding inclined surface; 43 - Cylindrical surface; 44 - Pressure surface; 5 - Annular pressing plate; 51 - Chamfered surface; 52 - Vertical cutting plane. Specific embodiments

[0022] To further elaborate on the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following will, in conjunction with the accompanying drawings and preferred embodiments, detail the specific embodiments, structures, features, and their effects of the present invention as follows.

[0023] The following will, in conjunction with the accompanying drawings, detail the technical solutions provided by each embodiment of the present invention.

[0024] The wet steam in a steam turbine is an important reason for the decrease in the efficiency of the steam turbine and the water erosion of the blades. The water droplets in the wet steam are divided into extremely fine water droplets (also known as primary water droplets) generated by spontaneous condensation and large water droplets (also known as secondary water droplets) ranging from about 10 μm to several hundred micrometers formed by the rupture of the water film on the surface of the blades (moving blades or stationary blades). The primary water droplets have better following behavior with the mainstream and are more difficult to separate from the mainstream. The separation of the secondary water droplets is less difficult. Therefore, means such as increasing the disturbance to the mainstream can increase the proportion of secondary water droplets.

[0025] Referring to Figures 1 to 5 As shown, an internal dehumidification structure for a steam turbine provided by an embodiment of the present invention is disposed between the steam turbine cylinder body and the steam turbine rotor 1. A first wall 2 is formed on the outer peripheral surface of the rotor 1. The dehumidification structure further includes a steam seal body 3 and dehumidification blades 4.

[0026] The steam seal body 3 is coaxially arranged on the rotor 1 and is rotationally and sealingly fitted with the outer peripheral wall of the rotor 1. The outer end of the steam seal body 3 is fixedly installed on the inner side of the cylinder body. The steam seal body 3 has a water collecting groove 31 coaxially arranged therewith, and a drainage pipeline 32 radially penetrating the steam seal body 3 is provided at one place of the water collecting groove 31; generally, there are several steam seal segments between the steam seal body 3 and the rotor 1 (as an existing technology, it will not be elaborated here). The steam seal segments are installed on the outer peripheral wall of the rotor 1, and the steam seal body 3 is sleeved outside the steam seal segments and can rotate relative to the steam seal segments while ensuring sealing performance. The piston can be referred to for this purpose to achieve the rotational and sealing fit between the rotor 1 and the steam seal body 3.

[0027] A plurality of dehumidification blades 4 are arranged and annularly connected to the first wall 2 with the axis of the rotor 1 as the center. A guiding wall is provided on each dehumidification blade 4; when the rotor 1 rotates, the wet steam inside the cylinder body enters the water collecting groove 31 through the guiding walls on the plurality of dehumidification blades 4 and is discharged through the drainage pipeline 32.

[0028] In summary, the dehumidification structure is arranged between the steam turbine cylinder and the rotor 1, making use of the position of the sealing structure originally used to separate different chambers, that is, the position where the steam seal body 3 is located, and integrating the dehumidification function therein, thus avoiding additional space occupation inside the cylinder chamber.

[0029] The steam seal body 3 plays a core supporting and sealing role in the whole structure. It is rotatably arranged on the rotor 1 and is rotationally and sealingly matched with it, and its outer end is fixed to the inner side of the cylinder. The water collecting tank 31 on the steam seal body 3 is used to collect the moisture in the wet steam, and the radially penetrating drain pipe 32 is the drainage channel for discharging the collected water. A number of dehumidification vanes 4 are annularly connected to the first wall 2 of the rotor 1 with the axis of the rotor 1 as the center. The guiding walls on each dehumidification vane 4 can change the flow direction of the wet steam so that it enters the water collecting tank 31. This annular arrangement ensures that when the rotor 1 rotates, the wet steam in all directions can be effectively guided to the water collecting tank 31.

[0030] Working principle: When the steam turbine rotor 1 rotates, the inside of the cylinder is filled with wet steam. Since the dehumidification vanes 4 are annularly arranged on the outer peripheral surface of the rotor 1, the wet steam comes into contact with the dehumidification vanes 4 during the flowing process. The guiding walls on the dehumidification vanes 4 change the flow direction of the wet steam and guide it into the water collecting tank 31 on the steam seal body 3. At the same time, the disturbance of the dehumidification vanes 4 causes some primary water droplets to condense into secondary water droplets with a larger diameter and better followability. The water collecting tank 31 collects the moisture in the wet steam guided by the guiding walls. Then the water is discharged through the drain pipe 32 that radially penetrates the steam seal body 3. The drain pipe 32 should be connected to a suitable drainage system to discharge the collected moisture from the steam turbine, thereby realizing the function of dehumidifying inside the steam turbine.

[0031] Therefore, in this embodiment, for most of the existing dehumidification structures designed inside the cylinder chamber, they will occupy the chamber space and have an adverse impact on the flow-through efficiency and blade arrangement. This application integrates the dehumidification structure onto the steam seal structure, making use of the position where the sealing structure originally needs to be set (because some chambers of the steam turbine need to be provided with steam extraction ports, and the steam seal body 3 is installed between the rotor 1 and the cylinder to separate the two chambers and achieve sealing), without the need to additionally arrange dehumidification components inside the chamber, avoiding occupying the chamber space, being beneficial to improving the utilization rate of the internal space of the steam turbine, optimizing the flow-through path, improving the flow-through efficiency, and at the same time being more convenient for the reasonable arrangement of the blades. In addition, by means of the steam seal body 3, both the sealing function between different chambers of the steam turbine and the dehumidification function are realized.

[0032] Through the guiding walls of the dehumidification vanes 4, the wet steam can be effectively guided to the water collecting tank 31, making use of the power generated by the rotation of the rotor 1 and the steam flow characteristics, and improving the dehumidification efficiency. Timely discharging the moisture in the wet steam reduces the erosion of components such as the steam turbine blades by the moisture, which helps to extend the service life of the steam turbine.

[0033] In some practical applications, referring to Figures 2 to 4 As shown, two adjacent surfaces of the dehumidification blade 4 coincide with or are attached to the first wall 2 and the outer peripheral wall of the rotor 1 respectively. Generally, the dehumidification blade 4 is integrally formed with the rotor 1, or the dehumidification blade 4 can be made into a separated structure and fixed and installed by fasteners such as bolts.

[0034] In some practical applications, referring to Figures 2 to 4 As shown, the diversion wall is composed of an inclined working surface 41 and a diversion inclined surface 42 located adjacent to the working surface 41 and facing the first wall 2 (generally, the diversion inclined surface 42 is inclined along the axial direction of the rotor 1 and the inclination angle is 105°-115°, and in actual production applications, 110°40′ is adopted); wherein, when the rotor 1 rotates, part of the wet steam impacts on the working surface 41 and flows into the water collecting tank 31 along the working surface 41; when the rotor 1 rotates, part of the wet steam parallel or tending to be parallel to the axial direction of the rotor 1 impacts on the diversion inclined surface 42 and flows into the water collecting tank 31 along the diversion inclined surface 42.

[0035] During the operation of the steam turbine, the rotor 1 rotates at a high speed, and the flow state of the wet steam in the cylinder is complex. The wet steam can be roughly divided into two types of flow directions. One type is the steam with a certain radial component, and the other type is the steam parallel or tending to be parallel to the axial direction of the rotor 1. For the wet steam with a radial component, as the rotor 1 rotates, it will directly impact on the working surface 41 of the diversion wall. Due to the inclined design of the working surface 41, the wet steam flows towards the water collecting tank 31 along the inclined direction of the working surface 41 after impact. At the same time, the working surface 41 does work on the steam in this process, further pushing the liquid water into the water collecting tank 31. For the wet steam parallel or tending to be parallel to the axial direction, they will impact on the diversion inclined surface 42. The diversion inclined surface 42 is inclined along the axial direction and has a smooth surface, enabling this part of the steam to smoothly change the flow direction and flow into the water collecting tank 31 along the diversion inclined surface 42, avoiding the vertical impact of the steam on the dehumidification blade 4 and causing loss of flow energy. Through the synergistic effect of the working surface 41 and the diversion inclined surface 42 of the diversion wall, wet steam with different flow directions can be effectively guided to the water collecting tank 31, achieving efficient collection and diversion guidance of the wet steam.

[0036] In some practical applications, referring to Figures 2 to 4 As shown, the outer end of the dehumidification blade 4 is set as a cylindrical surface 43 coaxial and of the same diameter as the outer diameter part of the first wall 2 of the rotor 1. The cylindrical surface 43 is an adjacent surface to the working surface 41, and the cylindrical surface 43 is also an adjacent surface to the diversion inclined surface 42. The top cylindrical surface 43 is consistent with the shaft surface of the rotor 1, which can ensure the top stiffness of the dehumidification pressing piece and is convenient for processing.

[0037] In some practical applications, based on any of the above embodiments of the dehumidification blade 4: referring to Figures 2 to 4As shown, the dehumidifying blade 4 also has a pressure surface 44 on the side opposite to the working surface 41, and this pressure surface 44 is perpendicular to the outer peripheral wall of the rotor 1. The pressure surface 44 is perpendicular to the surface of the rotor 1 and does not do work on the steam.

[0038] For the dehumidifying blade 4 described above: The diameter of the part of the rotor 1 where the dehumidifying blade 4 is located is 426 mm, the height of the dehumidifying blade 4 in the radial direction of the rotor 1 is 53 mm, the span between two adjacent dehumidifying blades 4 is 23°, and the span of the cylindrical surface 43 of each dehumidifying blade 4 is 2°.

[0039] In some other practical applications, referring to Figures 1 to 5 As shown, an annular pressing plate 5 is also coaxially installed on the steam seal body 3. The inner end of the annular pressing plate 5 is provided with two adjacent chamfered surfaces 51 arranged obliquely. The connection part of the two chamfered surfaces 51 is located outside the opening of the water collecting groove 31, and the chamfered surface 51 close to the water collecting groove 31 is inclined and transitions into the interior of the water collecting groove 31.

[0040] When the steam turbine rotor 1 rotates and the wet steam flows in the cylinder body, part of the wet steam will approach the area of the steam seal body 3. Due to the design of the chamfered surface 51 at the inner end of the annular pressing plate 5, when the wet steam contacts the annular pressing plate 5, it will be guided by the outer chamfered surface 51. The chamfered surface 51 close to the water collecting groove 31, because it is inclined and transitions into the interior of the water collecting groove 31, can smoothly introduce the wet steam into the water collecting groove 31.

[0041] The other inner chamfered surface 51 close to the water collecting groove 31 and the connection part of the two chamfered surfaces 51 act together to form a steam flow path outside the opening of the water collecting groove 31. So that the steam after being guided by the dehumidifying blade 4 impacts on the inner chamfered surface 51, thereby collecting the steam into the water collecting groove 31. This design prevents the steam from entering the water collecting groove 31 and overflowing. By guiding the wet steam into the water collecting groove 31 through the chamfered surface 51 of the annular pressing plate 5, more wet steam can smoothly enter the water collecting groove 31 compared to when there is no such structure, thus improving the dehumidification efficiency.

[0042] In some practical applications, based on the above design of the annular pressing plate 5: Referring to Figures 2 to 3 As shown, an annular guiding surface 33 coaxial with it is also formed on the steam seal body 3. This annular guiding surface 33 extends obliquely outward from the inner end of the steam seal body 3 (the included angle between the annular guiding surface 33 and its axis is set to 66° - 68°, and 67° is adopted in practical applications); the wet steam impacts on the annular guiding surface 33 along the guiding wall and impacts on the chamfered surface 51 close to the water collecting groove 31 through this annular guiding surface 33. The design of this annular guiding surface 33 facilitates the separated liquid water to enter the water collecting groove 31 and plays a guiding role.

[0043] In some practical applications, based on any of the above embodiments: inside the water collecting tank 31 and on the side close to the rotor 1, a water storage channel 34 coaxial with and recessed inward is formed (such as Figure 2 ), the drain pipeline 32 is located at the lowest position of the water collecting tank 31. The recessed setting of the water storage channel 34 enables the steam above the inside of the cylinder block to enter the water collecting tank 31 and then concentrate in the water storage channel 34, avoiding the outflow of the collected water. At the same time, it also plays a role in guiding the water and guiding the water into the drain pipeline 32 below.

[0044] In addition, it should be noted that the annular pressing plate 5 is divided into an upper half pressing plate and a lower half pressing plate for easy installation. The upper and lower pressing plates are provided with positioning card slots, and the pressing plate is connected to the intermediate steam seal body 3 by screws. The upper half pressing plate is provided with 22 through holes. To avoid interference with some structures on the steam seal body 3, vertical cutting planes 52 are respectively provided on the left and right sides of the upper half pressing plate. The lower half pressing plate is provided with 18 through holes. To avoid interference with the outer cylinder of the steam turbine, cutting planes are provided on the left and right sides and the bottom of the lower half pressing plate.

[0045] The above is only a preferred embodiment of the present invention and does not impose any form of limitation on the present invention. Although the present invention has been disclosed above with the preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments with equivalent changes within the scope of the technical solution of the present invention. However, as long as it does not depart from the content of the technical solution of the present invention, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. An internal dehumidification structure of a steam turbine, which is arranged between the steam turbine cylinder body and the steam turbine rotor (1), is characterized in that, A first wall (2) is formed on the outer peripheral surface of the rotor (1). The dehumidification structure further includes: A gland body (3) is coaxially arranged on the rotor (1) and is in rotary sealing fit with the outer peripheral wall of the rotor (1). The outer end of the gland body (3) is fixedly installed on the inner side of the cylinder body. A water collecting groove (31) coaxially arranged with it is provided on the gland body (3), and a drain pipe (32) radially penetrating the gland body (3) is provided at one place of the water collecting groove (31); A plurality of dehumidification blades (4) are configured and annularly connected to the first wall (2) with the axis of the rotor (1) as the center. A diversion wall is provided on each dehumidification blade (4); When the rotor (1) rotates, the wet steam inside the cylinder body enters the water collecting groove (31) through the diversion walls on the plurality of dehumidification blades (4) and is discharged through the drain pipe (32).

2. The internal dehumidification structure of a steam turbine according to claim 1, characterized in that, Two adjacent surfaces of the dehumidification blade (4) coincide with or are in contact with the first wall (2) and the outer peripheral wall of the rotor (1) respectively.

3. The internal dehumidification structure of a steam turbine according to claim 2, characterized in that, The dehumidification blade (4) is integrally formed with the rotor (1).

4. A steam turbine internal dehumidification structure according to claim 1, characterized in that, The diversion wall is composed of an inclined working surface (41) and a diversion inclined surface (42) located on the adjacent side of the working surface (41) and facing the first wall (2). Among them, when the rotor (1) rotates, part of the wet steam impacts on the working surface (41) and enters the water collecting groove (31) along the working surface (41); when the rotor (1) rotates, part of the wet steam parallel or tending to be parallel to the axial direction of the rotor (1) impacts on the diversion inclined surface (42) and enters the water collecting groove (31) along the diversion inclined surface (42).

5. The internal dehumidification structure of a steam turbine according to claim 4, characterized in that, The outer end of the dehumidification blade (4) is set as a cylindrical surface (43) coaxial and of the same diameter as the outer diameter part of the first wall (2) of the rotor (1). The cylindrical surface (43) is an adjacent surface to the working surface (41), and the cylindrical surface (43) is also an adjacent surface to the diversion inclined surface (42).

6. A steam turbine internal dehumidification structure according to claim 5, characterized in that, The dehumidification blade (4) also has a pressure surface (44) located on the opposite side of the working surface (41), and the pressure surface (44) is perpendicular to the outer peripheral wall of the rotor (1).

7. A steam turbine internal dehumidification structure according to claim 4, characterized in that, The diversion inclined surface (42) is inclined along the axial direction of the rotor (1) and the inclination angle is 105° - 115°.

8. A steam turbine internal dehumidification structure according to claim 1 or 4, characterized in that, An annular pressing plate (5) is also coaxially installed on the gland body (3). The inner end of the annular pressing plate (5) is provided with two inclined and adjacent chamfered surfaces (51). The connection part of the two chamfered surfaces (51) is located outside the opening of the water collecting groove (31). Among them, the chamfered surface (51) close to the water collecting groove (31) is inclined and transitions into the inside of the water collecting groove (31).

9. The internal dehumidification structure of a steam turbine according to claim 8, characterized in that, An annular diversion surface (33) coaxial with it is also formed on the gland body (3). The annular diversion surface (33) extends obliquely outward from the inner end of the gland body (3); the wet steam impacts on the annular diversion surface (33) along the diversion wall and impacts on the chamfered surface (51) close to the water collecting groove (31) through the annular diversion surface (33).

10. The internal dehumidification structure of a steam turbine according to claim 9, characterized in that, The included angle between the annular diversion surface (33) and its axis is set to 66° - 68°.

11. A steam turbine internal dehumidification structure according to claim 1, characterized in that, Inside the water collecting tank (31) and on one side close to the rotor (1), a water storage channel (34) coaxial with and recessed inward is formed, and the water drainage pipeline (32) is located at the lowest part of the water collecting tank (31).

12. A steam turbine internal dehumidification structure according to claim 5, characterized in that, The diameter of the part of the rotor (1) where the dehumidification blades (4) are located is 426 mm, the height of the dehumidification blades (4) in the radial direction of the rotor (1) is 53 mm, the span between two adjacent dehumidification blades (4) is 23°, and the span of the cylindrical surface (43) of each dehumidification blade (4) is 2°.

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