A dehumidification structure for the last stage blades of a steam turbine

Abstract

This utility model discloses a dehumidification structure for the last stage blades of a steam turbine, relating to the field of steam turbine technology. It includes a cylinder body, within which a steam chamber is formed. The cylinder body has a steam inlet and a steam outlet communicating with the steam chamber. The steam chamber contains a rotatable rotating component and a fixed component. Steam enters the steam chamber from the steam inlet to drive the rotating component to rotate. A cavity is formed within the rotating component. A connecting sleeve is rotatably mounted on the rotating component, and a connecting steam pipe extends from the connecting sleeve. The other end of the connecting steam pipe communicates with the steam outlet. The cavity of the rotating component is connected to the steam outlet via the connecting steam pipe. Hot air, after the condensed liquid settles at the steam outlet, flows back to the rotating component through the connecting steam pipe to heat the rotating component. Through the secondary use of steam heat, the heating operation of the rotating component is completed. Heating can evaporate the moisture adhering to the blades, preventing water erosion from affecting the blades' service life.

Description

Technical Field

[0001] This utility model belongs to the field of steam turbine technology, and specifically relates to a dehumidification structure for the last stage blades of a steam turbine. Background Technology

[0002] Water erosion is a common problem in the last few low-pressure stages of high-power steam turbine units and is one of the key factors restricting the development of steam turbines. When the steam temperature drops below its saturation temperature, it gradually condenses to produce a large number of water droplets. Some of these droplets deposit on the surface of the stationary blades to form a water film. At the same time, under the shear force of the airflow at the stationary blade outlet, they are eventually torn apart to form larger secondary water droplets, which erode the surface of the moving blades. Water erosion not only leads to a reduction in the overall efficiency of the steam turbine unit but may even cause blade breakage, seriously threatening the safe operation of the unit. Especially in recent years, with the continuous increase in the power of thermal and nuclear power steam turbine units and the large-scale flexible peak-shaving operation of the units, the water erosion problem of steam turbines has become increasingly prominent and intractable.

[0003] Currently, common dehumidification technologies for the last-stage blades of steam turbines include: 1. structural design dehumidification, and 2. materials and surface treatment. Among these, structural design dehumidification is the most widely used. It involves creating one or more narrow slots near the leading edge of the pressure surface of the stationary blades (nozzles) or moving blades (rotor blades). Due to centrifugal force (moving blades) or airflow bending (stationary blades), larger water droplets thrown against the wall by the mainstream are collected in the slots and then guided through holes or channels at the bottom of the slots to the annular condensate chamber after the stage or directly discharged to the condenser. However, this method also has significant drawbacks. It requires precise design of the slot location, shape, and number; improper design can lead to poor suction or even the removal of the mainstream steam, reducing efficiency. As for dehumidification through materials and surface treatment, this method is costly, complex, and its long-term reliability and durability in actual large-scale steam turbines remain challenges. Utility Model Content

[0004] The purpose of this invention is to provide a dehumidification structure for the last-stage blades of a steam turbine, thereby overcoming the challenge of effectively dehumidifying the turbine blades without damaging them. The specific technical solution is as follows:

[0005] A dehumidification structure for the last stage blades of a steam turbine includes a cylinder body, within which a steam chamber is formed. The cylinder body has a steam inlet and a steam outlet respectively communicating with the steam chamber. A fixed component is provided inside the steam chamber, and a rotating component is provided inside the steam chamber. When steam enters the steam chamber from the steam inlet, the rotating component is driven to rotate. A cavity is formed inside the rotating component, and a connecting sleeve is rotatably mounted on the rotating component. A connecting steam pipe is connected to the connecting sleeve, and the other end of the connecting steam pipe is connected to the steam outlet. The cavity of the rotating component is connected to the steam outlet through the connecting steam pipe. The hot gas after the condensed liquid settles at the steam outlet flows back to the rotating component through the connecting steam pipe to heat the rotating component.

[0006] Preferably, the rotating component includes a rotating shaft, a bearing, an impeller, and moving blades. The rotating shaft is rotatably mounted on the cylinder body via the bearing. The rotating shaft is provided with a plurality of impellers, and a plurality of moving blades are evenly distributed on the circumference of the impellers. A cavity is formed inside the rotating shaft, and a cavity is also formed inside the moving blades. A plurality of connecting channels are provided on the impellers, and the cavities of the moving blades communicate with the cavities through the connecting channels.

[0007] Preferably, the connecting sleeve is rotatably mounted on the rotating shaft.

[0008] Preferably, the steam inlet is located above the rotating shaft, with its steam inlet direction perpendicular to the downward direction; the steam outlet is located below the rotating shaft, with its steam outlet direction perpendicular to the downward direction.

[0009] Preferably, a condensate receiving cavity is installed at the steam outlet.

[0010] Preferably, the steam chamber is frustum-shaped and inclined toward the steam outlet.

[0011] Preferably, the diameter of the impeller mounted on the rotating shaft gradually increases along the inclination direction of the steam chamber.

[0012] Preferably, the fixed component includes a stationary impeller and stationary blades. The stationary impeller is installed in the steam chamber and is evenly distributed along the axial direction of the rotating shaft. A plurality of stationary blades are evenly distributed on the stationary impeller. The stationary impeller includes a first half-wheel and a second half-wheel that can be assembled together to form a complete wheel body.

[0013] Preferably, the stationary impeller and the impeller are spaced apart.

[0014] Preferably, the airflow direction of the stationary blade and the moving blade is opposite.

[0015] Compared with existing technologies, this utility model has the following beneficial effects:

[0016] 1. This utility model provides a dehumidification structure for the last stage blades of a steam turbine. The dehumidification structure is a structure in which the rotating shaft and moving blades are set as cavities. At the same time, the impeller has a connecting channel that can connect the two cavities. The hot gas after the sedimented liquid is diverted back to the cavity of the moving blades through the connecting steam pipe, thereby achieving a heating effect on the blades. The water adhering to the blades is evaporated by heating, thus avoiding water erosion that affects the service life of the blades.

[0017] 2. This utility model does not change the traditional turbine structure. It heats two adjacent stationary blades simultaneously through thermal radiation on the moving blades, thus "drying" the stationary blades. This dehumidification structure overcomes the problem of effectively dehumidifying the turbine blades without damaging them. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. The elements or parts in the drawings are not necessarily drawn to scale.

[0019] Figure 1 This is a schematic diagram of the overall structure of this utility model.

[0020] Figure 2 This is a schematic diagram of the structure of this utility model.

[0021] Figure 3 This is a schematic diagram of the stationary impeller structure of this utility model.

[0022] Explanation of key figure labels:

[0023] 100-Cylinder body, 110-Steam chamber, 120-Steam inlet, 130-Steam outlet, 200-Rotating component, 210-Shaft, 220-Impeller, 230-Moving blade, 300-Fixed component, 310-Stationary impeller, 311-First half-wheel, 312-Second half-wheel, 320-Stationary blade, 400-Connecting sleeve, 500-Connecting steam pipe. Detailed Implementation

[0024] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0025] In the description of this utility model, it should be noted that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "top surface", "bottom surface", "inner", "outer", "inner side", "outer side", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0026] In the description of this utility model, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. If the terms "first," "second," and "third" are used in the description, they are for descriptive purposes and to distinguish technical features, and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the sequential relationship of the indicated technical features.

[0027] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances. The embodiments of this utility model will now be described based on its overall structure.

[0028] Example

[0029] like Figures 1 to 3As shown, a dehumidification structure for the last stage blades of a steam turbine includes a cylinder body 100, within which a steam chamber 110 is formed. The cylinder body 100 has a steam inlet 120 and a steam outlet 130 respectively communicating with the steam chamber 110. A fixed component 300 is provided within the steam chamber 110, and a rotating component 200 is rotatably mounted within the steam chamber 110. When steam enters the steam chamber 110 from the steam inlet 120, it drives the rotating component 200 to rotate. The output end of the rotating component 200 outputs kinetic energy. A cavity is formed within the rotating component 200, and a connecting sleeve 400 is rotatably mounted on the rotating component 200. A connecting steam pipe 500 is connected to the 0, and the other end of the connecting steam pipe 500 is connected to the steam outlet 130. The cavity of the rotating component 200 is connected to the steam outlet 130 through the connecting steam pipe 500. The hot gas (which separates water vapor from liquid and hot gas and returns through the connecting steam pipe 500) after the condensed liquid settles at the steam outlet 130 flows back to the rotating component 200 through the connecting steam pipe 500 to heat the rotating component 200. By using the heat of the steam for a second time, the heating operation of the rotating component 200 is completed. Heating can evaporate the water attached to the blades, avoiding water erosion that affects the service life of the blades.

[0030] In some preferred embodiments, the rotating component 200 includes a rotating shaft 210, a bearing, an impeller 220, and moving blades 230. The rotating shaft 210 is rotatably mounted on the cylinder body 100 via the bearing. The rotating shaft 210 has a plurality of impellers 220. Further, the steam chamber 110 is frustum-shaped and inclined towards the steam outlet 130. The diameter of the impellers 220 on the rotating shaft 210 gradually increases along the inclination direction of the steam chamber 110. A plurality of moving blades 230 are evenly distributed on the circumference of the impellers 220. A cavity is formed inside the rotating shaft 210, and a cavity is also formed inside each moving blade 230. The impeller 220 has a plurality of connecting channels, and the cavities of the moving blades 230 communicate with the cavities through these connecting channels. A connecting sleeve 400 is rotatably mounted on the rotating shaft 210. The inner cavity of the connecting sleeve 400 communicates with the cavity of the rotating shaft 210.

[0031] In some preferred embodiments, the steam inlet 120 is located above the rotating shaft 210, with its steam inlet direction perpendicularly downward. The steam entering through the steam inlet 120 acts on the moving blade 230, driving the moving blade 230 to rotate the rotating shaft 210. Then, the steam is gradually transmitted along the axial direction of the rotating shaft 210, acting on the blades step by step. The steam outlet 130 is located below the rotating shaft 210, with its steam outlet direction perpendicularly downward. Since the steam carries a certain amount of moisture, when it comes into contact with the blade, the moisture carried in the steam condenses into a water film under the action of temperature difference and adheres to the blade. Under the rotation of the rotating shaft 210, due to the action of centrifugal force, the water film gathers into water droplets and is thrown to the blade crown and onto the cavity wall of the steam chamber 110. The collected water droplets slide down the cavity wall under the action of gravity and are discharged from the steam outlet 130 into the condensate receiving cavity (the steam outlet 130 is equipped with a condensate receiving cavity). At the same time, the steam introduced from the steam inlet 120 also flows to the steam outlet 130. Since the condensate receiving cavity installed at the steam outlet 130 is also in a closed state, the steam that reaches here, after separating the liquid, "flows back" into the cavity inside the rotating shaft 210 and is diverted by the connecting channel to the cavity inside the moving blade 230. Since the hot air flowing back itself still has a certain temperature, the moving blade 230 is "heated and dried" a second time by utilizing the temperature to evaporate the water film attached to its surface and prevent water erosion.

[0032] In some preferred embodiments, the fixed component 300 includes a stationary impeller 310 and stationary blades 320. The stationary impeller 310 is installed in the steam chamber 110 and is evenly distributed along the axial direction of the rotating shaft 210. A plurality of stationary blades 320 are evenly distributed on the stationary impeller 310. The stationary impeller 310 includes a first half-wheel 311 and a second half-wheel 312 that can be assembled into a complete wheel body. The stationary impeller 310 and the impeller 220 are spaced apart, so the heat radiated from the moving blades 230 also dries the two adjacent stationary blades 310. The airflow direction of the stationary blades 320 and the moving blades 230 is opposite. By alternating between the stationary and moving blades, the direction of steam transmission is continuously changed, increasing the steam's travel distance within the steam chamber 110 and improving steam utilization.

[0033] In summary, this invention provides a dehumidification structure for the last stage blades of a steam turbine. This structure incorporates a hollow shaft and moving blades, with the impeller having a connecting channel between the two cavities. A connecting steam pipe guides the hot gas after the settled liquid is drawn back into the cavity of the moving blades, achieving a heating effect on the blades. This heating evaporates the moisture adhering to the blades, preventing water erosion that could affect their service life. This invention does not alter the traditional steam turbine structure. Through thermal radiation from the moving blades, it simultaneously heats two adjacent stationary blades, effectively "drying" the stationary blades as well. This dehumidification structure overcomes the challenge of effectively dehumidifying the steam turbine blades without damaging them.

[0034] The foregoing description of specific exemplary embodiments of the present invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the present invention to the precise forms disclosed, and it is obvious that many changes and variations can be made based on the above teachings. Although embodiments of the present invention have been shown and described, these specific embodiments are merely explanations of the present invention and are not intended to limit the invention. The specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. The purpose of selecting and describing exemplary embodiments is to explain the specific principles of the present invention and its practical application, so that those skilled in the art, after reading this specification, can make modifications, substitutions, variations, and various choices and changes to the embodiments as needed without departing from the principles and spirit of the present invention, provided that such modifications, substitutions, variations, and choices and changes are within the scope of the claims of the present invention and are protected by patent law.

Claims

1. A dehumidification structure for a last stage blade of a steam turbine, comprising a cylinder body (100) in which a steam cavity (110) is formed, and a steam inlet (120) and a steam outlet (130) provided on the cylinder body (100) and communicating with the steam cavity (110) respectively, and a fixed part (300) provided in the steam cavity (110), characterized in that, The steam chamber (110) is provided with a rotating component (200), which can drive the rotating component (200) to rotate when steam enters the steam chamber (110) from the steam inlet (120). A cavity is formed inside the rotating component (200). A connecting sleeve (400) is rotatably installed on the rotating component (200). A connecting steam pipe (500) is connected to the connecting sleeve (400). The other end of the connecting steam pipe (500) is connected to the steam outlet (130). The cavity of the rotating component (200) is connected to the steam outlet (130) through the connecting steam pipe (500). The hot air after the condensed liquid settles at the steam outlet (130) flows back to the rotating component (200) through the connecting steam pipe (500) to heat the rotating component (200).

2. A moisture removal structure for a last stage blade of a steam turbine according to claim 1, characterized in that, The rotating component (200) includes a rotating shaft (210), a bearing, an impeller (220), and moving blades (230). The rotating shaft (210) is rotatably mounted on the cylinder body (100) via the bearing. The rotating shaft (210) is provided with a plurality of impellers (220). A plurality of moving blades (230) are evenly distributed on the circumferential surface of the impellers (220). A cavity is formed inside the rotating shaft (210). A cavity is also formed inside the moving blades (230). A plurality of connecting channels are provided on the impellers (220). The cavities of the moving blades (230) are connected to the cavities through the connecting channels.

3. A moisture removal structure for a last stage blade of a steam turbine according to claim 2, wherein The connecting sleeve (400) is rotatably mounted on the rotating shaft (210).

4. A moisture removal structure for a last stage blade of a steam turbine according to claim 2, wherein The steam inlet (120) is located above the rotating shaft (210), with its steam inlet direction perpendicular to the downward direction; the steam outlet (130) is located below the rotating shaft (210), with its steam outlet direction perpendicular to the downward direction.

5. The dehumidification structure for the last stage blades of a steam turbine according to claim 4, characterized in that, A condensate receiving cavity is installed at the steam outlet (130).

6. The dehumidification structure for the last stage blades of a steam turbine according to claim 2, characterized in that, The steam chamber (110) is frustum-shaped and is inclined toward the steam outlet (130).

7. The dehumidification structure for the last stage blades of a steam turbine according to claim 6, characterized in that, The diameter of the impeller (220) mounted on the rotating shaft (210) gradually increases along the inclination direction of the steam chamber (110).

8. The dehumidification structure for the last stage blades of a steam turbine according to claim 2, characterized in that, The fixed component (300) includes a stationary impeller (310) and stationary blades (320). The stationary impeller (310) is installed in the steam chamber (110) and is evenly distributed along the axial direction of the rotating shaft (210). A number of stationary blades (320) are evenly distributed on the stationary impeller (310). The stationary impeller (310) includes a first half-wheel (311) and a second half-wheel (312) that can be assembled into a complete wheel body.

9. A dehumidification structure for the last stage blades of a steam turbine according to claim 8, characterized in that, The stationary impeller (310) and the impeller (220) are spaced apart.

10. A dehumidification structure for the last stage blades of a steam turbine according to claim 8, characterized in that, The stationary blade (320) and the moving blade (230) have opposite airflow directions.

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