A steam turbine stationary blade

Abstract

The steam turbine vane provided by the present disclosure comprises an outer ring, a vane profile part arranged between the outer ring and an inner ring to form a steam flow channel, and the inner ring arranged inside the vane profile part. An inner ring steam seal tooth is arranged on the inner cylindrical surface of the inner ring, and an inner ring rotation blocking tooth is arranged on the inner cylindrical surface of the inner ring and located upstream of the inner ring steam seal tooth in the steam flow direction. The steam turbine vane provided by the present disclosure can improve the flow condition of the pressure stage inlet, reduce the rotation flow intensity at the steam seal, and improve the economic performance and operation stability of the steam turbine.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of steam turbines, in particular to a steam turbine stationary blade. BACKGROUND

[0002] In the current domestic power generation field, with the increasing proportion of new energy power generation installed capacity year by year, more and more thermal power units no longer only bear the basic load, but also need to bear the peak shaving function in coordination with the power grid dispatching, resulting in a wide range of frequent changes in unit load. The change of operation mode makes the regulating stage of the steam turbine have the characteristics of large enthalpy drop and large working condition change range. There is a large radial height difference between the regulating stage and the pressure stage, and in the limited space, the regulating stage wake needs to experience multiple turns to enter the pressure stage. The regulating stage adopts partial admission, and the regulating stage wake has the characteristics of discontinuity and unevenness in the circumferential direction. When the unit load changes, the speed ratio of the regulating stage changes, causing a large range of changes in the circumferential velocity of the regulating stage wake.

[0003] In the first pressure stage after the regulating stage, the design of the traditional stationary blade profile often ignores the adverse effects of the non-uniformity of the regulating stage wake on the inlet flow conditions, resulting in a significant decrease in the efficiency of the pressure stage, which affects the economic performance of the unit. The design of the inner ring steam seal of the traditional stationary blade often ignores the adverse effects of the circumferential component velocity of the regulating stage wake, so that the inner ring steam seal has a high pre-rotation speed, which reduces the stability of the steam turbine rotor and endangers the safe operation of the unit. SUMMARY

[0004] (I) Technical problems to be solved

[0005] In view of the above problems, the present disclosure provides a steam turbine stationary blade to at least partially solve the technical problems of low efficiency, low output power, poor economic performance and low rotor stability of the current steam turbine pressure stage.

[0006] (II) Technical solutions

[0007] The present disclosure provides a steam turbine stationary blade, comprising: an outer ring; a blade profile part arranged between the outer ring and an inner ring to form a steam flow passage; an inner ring arranged inside the blade profile part; an inner ring steam seal tooth arranged on the inner cylindrical surface of the inner ring; and an inner ring anti-rotation tooth arranged on the inner cylindrical surface of the inner ring and located upstream of the inner ring steam seal tooth in the steam flow direction.

[0008] According to an embodiment of the present disclosure, the blade profile part is a variable cross-section cambered twisted blade.

[0009] According to an embodiment of the present disclosure, the cross-sectional area of the blade profile part gradually decreases from the root to the top blade profile along the blade height direction.

[0010] According to an embodiment of the present disclosure, the inner ring seal teeth adopt high-low tooth comb teeth, helical teeth or flat teeth seal.

[0011] According to an embodiment of the present disclosure, the axial width of the inner ring is greater than the axial width of the outer ring.

[0012] According to an embodiment of the present disclosure, in the passage of steam flow, the steam inlet side end face of the inner ring is located in the upstream direction of the steam inlet side end face of the outer ring.

[0013] According to an embodiment of the present disclosure, the ratio of the grid spacing of the blade root section of the blade profile part to the blade profile chord length is less than or equal to a first preset threshold value.

[0014] According to an embodiment of the present disclosure, the two adjacent blades of the blade profile part form a blade channel with a throat width to passage length ratio less than or equal to a second preset threshold value at the root.

[0015] According to an embodiment of the present disclosure, the anti-rotation teeth of the inner ring are arranged at a preset angle with the axis of the inner ring / outer ring.

[0016] According to an embodiment of the present disclosure, the inclination angle of the anti-rotation teeth of the inner ring relative to the reference direction is the same as the inclination angle of the blade profile part.

[0017] (Three) beneficial effects

[0018] The steam turbine stator blade provided by the present disclosure has at least the following beneficial effects:

[0019] 1. The specially designed blade profile part regulates and restricts the evolution and development of the tail flow of the governing stage, improves the uniformity of the flow distribution at the inlet of the stator blade of the pressure stage, suppresses large-scale angle of attack flow separation, thereby improving the efficiency and output power of the pressure stage.

[0020] 2. The specially designed inner ring seal tooth structure improves the sealing performance of the inner ring seal of the stator blade of the pressure stage, reduces the seal leakage, thereby improving the efficiency and output power of the pressure stage. At the same time, the rotational flow intensity of the inner ring seal leakage into the seal chamber is reduced, the force of the seal leakage on the rotor is reduced, and the running stability of the steam turbine rotor is improved.

[0021] 3. The stator blade of the present disclosure has simple structure, easy manufacturing, easy modification and upgrading on existing steam turbines, and has wide application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0022] The above and other objects, features and advantages of the present disclosure will become more apparent from the following description of embodiments of the present disclosure taken in conjunction with the accompanying drawings, in which:

[0023] Figure 1This schematically illustrates a complete assembly diagram of a turbine stationary blade provided in an embodiment of the present disclosure;

[0024] Figure 2 A schematic front view of a turbine stationary blade provided in an embodiment of this disclosure is shown.

[0025] Figure 3 A schematic top view of a turbine stationary blade provided in an embodiment of this disclosure is shown.

[0026] Figure 4 The schematic illustration shows the flow field distribution of the first-stage inlet of the pressure stage provided in the embodiments of this disclosure, using conventional stationary blades and stationary blades of the structure of this disclosure.

[0027] Explanation of reference numerals in the attached figures

[0028] 1-Outer ring;

[0029] 2- Blade profile section;

[0030] 3-Inner ring;

[0031] 4-Inner ring steam seal teeth;

[0032] 5-Inner ring stop gear. Detailed Implementation

[0033] The embodiments of the present disclosure will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the disclosure. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the present disclosure for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of the present disclosure.

[0034] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0035] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0036] This disclosure provides a turbine stationary blade that reduces the swirling intensity of steam leakage from the inner annular steam seal entering the steam seal chamber, thereby reducing the force exerted by the steam seal leakage on the rotor and improving the operational stability of the turbine rotor.

[0037] Figure 1 Fig. 1 schematically shows an assembly view of a turbine stator vane according to an embodiment of the present disclosure.

[0038] Figure 2 Fig. 2 schematically shows a front view of a turbine stator vane according to an embodiment of the present disclosure. Figure 3 Fig. 3 schematically shows a top view of a turbine stator vane according to an embodiment of the present disclosure.

[0039] Figure 1 Fig. 4 schematically shows a turbine stator vane according to an embodiment of the present disclosure. Figure 2 Figure 3 Fig. 5 schematically shows a turbine stator vane according to an embodiment of the present disclosure.

[0040] Fig. 6 schematically shows a turbine stator vane according to an embodiment of the present disclosure.

[0041] Fig. 7 schematically shows a turbine stator vane according to an embodiment of the present disclosure.

[0042] Fig. 8 schematically shows a turbine stator vane according to an embodiment of the present disclosure.

[0043] Fig. 9 schematically shows a turbine stator vane according to an embodiment of the present disclosure.

[0044] Fig. 10 schematically shows a turbine stator vane according to an embodiment of the present disclosure.

[0045] Fig. 11 schematically shows a turbine stator vane according to an embodiment of the present disclosure. ​​

[0046] In the embodiments of the present disclosure, the inner ring 3 is arranged inside the blade profile portion 2, and the axial width is greater than the axial width of the outer ring 1, wherein the axial width is the size along the axial direction (i.e., the length direction).

[0047] Exemplarily, the axial width B1 of the inner ring 3 is 2.28 times the axial width B2 of the outer ring 1.

[0048] Further, in the steam flow channel, the steam inlet side end surface (the end surface portion adjacent to the steam inlet) of the inner ring 3 is located in the upstream direction of the steam inlet side end surface of the outer ring 1.

[0049] Exemplarily, the distance between the steam inlet side end surface of the inner ring 3 and the steam inlet side end surface of the outer ring 1 is 1.28 times the axial width of the outer ring 1.

[0050] In some exemplary embodiments, the inner ring steam seal teeth 4 are arranged on the inner cylindrical surface of the inner ring 3, and high-low tooth comb teeth, helical teeth or flat teeth steam seals can be used.

[0051] Among them, the high-low tooth comb steam seal tooth profile is formed by alternately arranging high teeth and low teeth, forming staggered sealing gaps, which not only effectively prevents the axial leakage of fluid, but also generates a certain pumping effect during rotation, helping to guide the leaked fluid back to the main flow channel, thereby improving the overall sealing efficiency. The helical tooth steam seal optimizes the flow path of the fluid between the teeth through the inclined tooth design, reduces the vortex and energy loss caused by the direct impact of the fluid on the tooth surface, and the helical tooth can also adapt to the slight yaw of the shaft to a certain extent, maintaining stable sealing contact.

[0052] The flat tooth steam seal has a flat tooth surface that is easy to process and maintain, and can effectively block most fluid leakage, and is suitable for low-speed or environments where the sealing requirement is not particularly strict.

[0053] On the basis of the above-mentioned embodiments, in the present embodiment, the inner ring rotation blocking teeth 5 are arranged on the inner cylindrical surface of the inner ring 3, which are used to prevent or slow down the rotation speed of the rotating part, or to provide a certain specific damping effect. At the same time, in the steam flow direction, the inner ring rotation blocking teeth 5 are located upstream of the inner ring steam seal teeth 4, i.e., the inner ring rotation blocking teeth 5 are located in front of the front end of the inner ring steam seal teeth 4, so as to utilize the damping effect of the inner ring rotation blocking teeth 5 to reduce the fluid leakage at the inner ring steam seal teeth 4 or the vibration of the rotating part.

[0054] Further, the inner ring anti-rotation teeth 5 are arranged at a preset angle (e.g. 45°) with respect to the axial direction (i.e. the centerline direction of the device) to prevent steam or other fluids from leaking from the high-pressure area to the low-pressure area, thereby improving the sealing performance of the device and enhancing its adaptability to changes in pressure difference, ensuring stable operation of the device under various working conditions. The installation angle direction of the inner ring anti-rotation teeth 5 is the same as that of the blade profile portion 2, i.e. the inclination angle of installation is the same as that of the blade profile portion 2 with respect to the reference direction (such as the axial direction, the radial direction, or the centerline direction of the device), thereby ensuring that the fluid is consistently and coordinately guided when flowing through these two components, reducing the turbulence of fluid flow, and improving the overall fluid dynamics efficiency. In addition, the consistency of the installation angle of the inner ring anti-rotation teeth 5 and the blade profile portion 2 also allows the device to cut the fluid in a more stable manner during rotation, whether it is the inner ring anti-rotation teeth 5 or the blade profile portion 2, reducing vibration and noise caused by fluid impact, and prolonging the service life of the device. At the same time, it also helps to improve the overall rigidity and stability of the device, so that the device can still maintain excellent sealing effect and operating performance when subjected to large pressure or load.

[0055] Embodiment 1:

[0056] When a certain 300MW steam turbine operates at 75% rated load (tha) condition, the absolute outlet angle of the moving blade is only 36 degrees. As shown in the left schematic diagram, under this specific working condition, if a conventional static blade design is used, the flow distribution at the inlet of the first stage static blade of the pressure stage will be significantly uneven, resulting in a non-negligible negative impact on the overall performance of the steam turbine. In order to solve this problem, after using the static blade of the present disclosure, as shown in the right schematic diagram, the flow uniformity at the inlet of the first stage static blade of the pressure stage is greatly improved. In terms of performance, the total output of the governing stage and the first stage of the pressure stage increases by about 380kw compared to before, which accounts for 0.15% of the total machine output. Figure 4 Figure 4 It can be understood that the static blade in the embodiment of the present disclosure effectively improves the flow conditions at the inlet of the pressure stage and improves the efficiency of the pressure stage through the specially designed blade profile portion. At the same time, the static blade reduces the steam leakage amount of the steam seal and effectively reduces the rotational flow intensity at the inner ring steam seal, thereby improving the operating stability of the rotor of the steam turbine.

[0057] It can be understood that the static blade in the embodiment of the present disclosure effectively improves the flow conditions at the inlet of the pressure stage and improves the efficiency of the pressure stage through the specially designed blade profile portion. At the same time, the static blade reduces the steam leakage amount of the steam seal and effectively reduces the rotational flow intensity at the inner ring steam seal, thereby improving the operating stability of the rotor of the steam turbine.

[0058] ​Those skilled in the art can understand that the features recited in various embodiments of the present disclosure and / or claims can be combined and / or integrated in various combinations, even if such combinations or integrations are not expressly recited in the present disclosure. In particular, the features recited in various embodiments of the present disclosure and / or claims can be combined and / or integrated in various combinations without departing from the spirit and teachings of the present disclosure. All such combinations and / or integrations fall within the scope of the present disclosure.

[0059] While the present disclosure has been shown and described with reference to certain exemplary embodiments thereof, it is to be understood that the present disclosure is not limited to the above- described embodiments but encompasses various changes, modifications and equivalents thereof. Therefore, the spirit and scope of the present disclosure should not be limited to the above-described embodiments but should be determined by the appended claims together with the full text thereof.

Claims

1. A steam turbine stationary vane located in the first pressure stage after the governing stage, characterized in that, The utility model relates to a steam turbine blade, comprising: an outer ring; a blade profile part arranged between the outer ring and the inner ring to form a steam flow channel, the blade profile part gradually reduces the cross-sectional area of the blade profile along the blade height direction from the inner ring to the outer ring, the ratio of the pitch of the blade root cross section of the blade profile part to the chord length of the blade profile is less than or equal to a first preset threshold, and the ratio of the throat width of the two adjacent blades of the blade profile part at the root to the channel length is less than or equal to a second preset threshold; an inner ring arranged inside the blade profile part, the axial width of the inner ring is greater than the axial width of the outer ring, and the steam inlet side end surface of the inner ring is located in the upstream direction of the steam inlet side end surface of the outer ring in the steam flow channel; an inner ring steam seal tooth arranged on the inner cylindrical surface of the inner ring; an inner ring rotation resistance tooth arranged on the inner cylindrical surface of the inner ring and located in the upstream position of the inner ring steam seal tooth in the steam flow direction.

2. The turbine vane of claim 1, wherein The blade profile part is a variable cross-section twisted blade.

3. The turbine vane of claim 1, wherein The inner ring steam seal tooth adopts a high-low tooth comb tooth, an inclined tooth or a flat tooth steam seal.

4. The turbine vane of claim 1, wherein The inner ring rotation resistance tooth is arranged at a preset angle with the axial direction of the inner ring / outer ring.

5. The turbine vane of claim 1 or 4, wherein The inclination angle of the inner ring rotation resistance tooth relative to the reference direction is the same as the inclination angle of the blade profile part.

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