CN115126549A - Root of a turbine blade and turbine blade - Google Patents

Abstract

The invention belongs to the technical field of turbine rotating machinery, and discloses a blade root of a turbine blade and the turbine blade. The blade root includes root upper portion, neck and the root lower part that connects gradually in proper order, and root upper portion is used for being connected with the blade body of turbine blade, and the one end and the root lower part of neck are the connection of falling T style of calligraphy, and the other end is connected with root upper portion, and root upper portion is equipped with first heavy groove that subtracts, and the neck is equipped with the second and subtracts heavy groove, adopts fillet transition formation rim loading face between the side of root lower part top surface and neck. The first weight-reducing grooves and the second weight-reducing grooves are formed in the upper portion of the root and the neck portion, so that the weight of the blade root is reduced, and the blade root is light; the top surface of the lower part of the root and the side surface of the neck are connected to form a wheel rim bearing surface through fillet transition, so that the line type of the blade root is optimized, the stress concentration at the wheel groove of the blade root is not easy to generate, and the risk of blade root fracture is effectively reduced.

Description

Root of a turbine blade and turbine blade

technical field

The invention relates to the technical field of turbo rotating machinery, in particular to a blade root of a turbo blade and a turbo blade.

Background technique

In the research and development of key equipment for the power generation cycle of the supercritical carbon dioxide system, the structural design of the turbomachinery is the focus of researchers. Turbine blades are the key components of supercritical carbon dioxide turbomachinery, directing fluid flow in a certain direction and propelling the rotor to rotate. The vanes mounted on the casing become stationary vanes or guide vanes, and the vanes mounted on the rotor become moving vanes. In turbomachinery running at high speed, any blade breakage will cause vibration and even damage to the equipment. Therefore, the structural design and vibration intensity of the blade are very important to the safety and reliability of the unit. Steam turbine blades have higher requirements in terms of manufacturing processes.

The leaf is usually composed of three parts: the leaf body, the leaf root and the leaf tip. The blade body is the working part of the blade, and the air flow channel is formed between the adjacent blade bodies. When the steam flows through the air flow channel, the kinetic energy is converted into mechanical energy; the blade is fixedly connected to the impeller or drum through the blade root; the blade tip refers to the top of the blade, Short blades and medium-long blades are usually connected together by shrouds at the tip of the blade to form a blade group. At present, a blade root with a simple structure is often used on the rotor, as shown in Figure 1. Because the turbomachinery is in a high temperature and high pressure working environment, it has the characteristics of high speed and frequent start-up, the blade root is affected by centrifugal force, excitation force and temperature field during operation, and the connection between the lower part 1 of the blade root and the neck 2 It is easy to produce great stress concentration. If the maximum stress value is not reduced, accidents such as blade breakage will occur.

The blade root in the prior art has a single structure and heavy weight, and a large stress is easily generated at the groove of the blade root, and the quality of the blade has a great influence on the stress at the blade root under high rotational speed. Therefore, it is urgent to propose a blade root that is lightweight and less prone to stress concentration to solve the above problems.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a blade root of a turbine blade, the blade root has a small weight and is less prone to stress concentration at the wheel groove.

For this purpose, the present invention adopts the following technical solutions:

A blade root of a turbine blade, comprising: an upper part of the root part, a neck part and a lower part of the root part, which are connected in sequence; the upper part of the root part is used to connect with the blade body of the turbine blade, and one end of the neck part is connected with the lower part of the root part in an inverted T shape, The other end is connected with the upper part of the root; the upper part of the root is provided with a first weight-reducing groove; the top surface of the lower part of the root and the side surface of the neck adopt a rounded transition to form a wheel rim bearing surface.

Optionally, the neck is provided with a second weight-reducing groove.

Optionally, the wheel rim bearing surface is formed by connecting a plurality of arc surfaces with different radii in sequence.

Optionally, the upper part of the root is connected with the neck in a T-shape, and the opening direction of the first weight-reducing groove is set toward the lower part of the root.

Optionally, the cross-sectional profile of the first weight-reducing groove along the spanwise direction of the blade is polygonal or arc-shaped.

Optionally, the number of the first weight reduction grooves is two, and the two first weight reduction grooves are arranged symmetrically about the central axis of the neck.

Optionally, the cross-sectional shape of the second weight reduction groove along the blade span direction is polygonal or elliptical.

Optionally, the top end of the lower part of the root is provided with an upper chamfer.

Optionally, the bottom end of the lower part of the root is provided with a lower chamfer.

Another object of the present invention is to provide a turbine blade, which has good manufacturability, low weight and relatively low maximum stress, is suitable for most turbine blades installed in the circumferential direction, and is beneficial to popularization .

For this purpose, the present invention adopts the following technical solutions:

A turbine blade includes a blade body and the blade root of the above-mentioned turbine blade.

Beneficial effects:

The blade root of the turbine blade provided by the present invention reduces the weight of the blade root by setting the first weight-reducing groove in the upper part of the root, and realizes the lightweight of the blade root; the connection surface between the top surface of the lower part of the root and the side surface of the neck adopts a circular The angle transition forms the bearing surface of the rim, which optimizes the line shape of the blade root, so that the stress concentration that is not easily generated at the groove of the blade root reduces the maximum stress on the bearing surface of the rim, and effectively reduces the risk of blade root fracture. Good manufacturability, suitable for most turbine blades installed in the circumferential direction, which is conducive to promotion.

Description of drawings

Fig. 1 is the structural representation of the blade root in the prior art;

Figure 2 is a schematic structural diagram of a blade root provided by the present invention.

In the picture:

100, the upper part of the root; 101, the first weight reduction groove; 200, the neck; 201, the second weight reduction groove; 300, the lower part of the root; 301, the rim bearing surface; 302, the upper chamfer;

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention. In addition, it should be noted that, for the convenience of description, the drawings only show some but not all structures related to the present invention.

In the description of the present invention, unless otherwise expressly specified and limited, the terms "connected", "connected" and "fixed" should be understood in a broad sense, for example, it may be a fixed connection, a detachable connection, or an integrated ; It can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood in specific situations.

In the present invention, unless otherwise expressly specified and limited, a first feature "on" or "under" a second feature may include the first and second features in direct contact, or may include the first and second features Not directly but through additional features between them. Also, the first feature being "above", "over" and "above" the second feature includes the first feature being directly above and obliquely above the second feature, or simply means that the first feature is level higher than the second feature. The first feature is "below", "below" and "below" the second feature includes the first feature being directly below and diagonally below the second feature, or simply means that the first feature has a lower level than the second feature.

In the description of this embodiment, the terms "upper", "lower", "right", etc. are based on the orientation or positional relationship shown in the accompanying drawings, which are only for convenience of description and simplified operation, rather than indicating Or imply that the device or element referred to must have a particular orientation, be constructed and operate in a particular orientation, and therefore should not be construed as limiting the invention. In addition, the terms "first" and "second" are only used for distinction in description, and have no special meaning.

Turbine refers to a power type fluid machine with fluid blades such as steam turbine, expander, turbine, compressor, etc. The working principle of the turbine is that the rotor equipped with blades rotates at a high speed. When the fluid (gas or liquid) flows through the channels between the blades, the interaction force between the blades and the fluid is generated, thereby realizing the conversion of energy. Turbine blades are the components used to guide fluid flow in turbines, and the rationality of their structural design is very important. The main body of the turbine blade is the blade body, and its size is related to the flow capacity of the fluid. The blade tip is connected by a shroud to form a blade group, and the blade is connected to the impeller or drum through the blade root. Turbine has the characteristics of high temperature, high pressure, high speed and frequent start-up. If the moving blade installed on the rotor breaks down during the high-speed operation of the turbine, it will cause equipment vibration and easily cause damage to the equipment. It can be seen that the structural design of the blade is not only related to the working efficiency of the unit, but also is of great importance to the safety and reliability of the equipment.

The rotor in the prior art often adopts a blade root with a single structure, and the weight is large, and the stress is concentrated at the wheel groove of the blade root. Therefore, the quality of the blade rotating at a high speed has a great influence on the stress at the blade root, and the blade is easy to be in the blade. The root is broken, affecting the normal operation of the equipment. The blade root provided by the present invention can effectively solve the above problems.

The blade root of the turbine blade provided by the present invention, as shown in FIG. 2 , includes an upper root portion 100 , a neck portion 200 and a lower root portion 300 connected in sequence. The upper part 100 of the root part is used to connect with the blade body of the turbine blade, one end of the neck part 200 is connected with the lower part 300 of the root part in an inverted T shape, the other end is connected to the upper part 100 of the root part, and the upper part 100 of the root part is provided with a first weight reduction groove 101, A rounded transition is used between the top surface of the lower part 300 of the root and the side surface of the neck 200 to form the bearing surface of the wheel rim.

The blade root reduces the weight of the blade root by disposing the first weight-reducing groove 101 in the upper part 100 of the root, thereby realizing the weight reduction of the blade root. At the connection surface between the top surface of the lower part 300 of the root and the side surface of the neck 200, a rounded transition is used to form the wheel rim bearing surface 301, which optimizes the line shape of the blade root, makes it difficult to generate stress concentration at the wheel groove of the blade root, and reduces the The maximum stress on the rim bearing surface 301 effectively reduces the risk of blade root fracture, has good manufacturability, is suitable for most circumferentially installed turbine blades, and is conducive to popularization.

Referring to Fig. 2, the blade root is an I-shaped left-right symmetrical structure as a whole, the upper end is the root upper part 100 arranged horizontally, the lower end is the lower root part 300 arranged horizontally, the upper part 100 of the root part and the lower part 300 of the root part are parallel to each other, and there is a Vertically arranged necks 200 are attached. The upper part 100 of the root part and the neck part 200 are connected in a T-shape, and the upper part 100 of the root part is provided with a first weight reduction groove 101. In order to open the weight reduction groove, compared with the blade root in the prior art, the blade root in this embodiment is The upper part 100 of the root is widened, and the shape is changed from tall and narrow to thick. In the illustration, the opening direction of the first weight-reducing groove 101 is set toward the lower part 300 of the root, the cross-sectional shape along the spanwise direction of the blade is an inverted U-shape, and a rounded transition is adopted at the apex. It is understood that the rounded transition can be effectively reduced. The stress is concentrated to prevent cracks at the apex due to excessive stress. In other embodiments, the cross-sectional shape of the first weight-reducing groove 101 in the spanwise direction of the blade may be arc, polygon or other shapes, and the cross-sectional area thereof is set according to the strength requirements of the blade root. The first weight-reducing groove 101 may also be a square, circular or other shaped through hole opened in the upper part 100 of the root, and the number thereof is set according to the requirements of light-weighting. It should be noted here that the "weight reduction groove" is only a name given to a component for convenience of description, and does not limit its shape or structure. Further, the number of the first weight-reducing grooves 101 is an even number, and they are arranged in parallel with respect to the central axis of the neck 200 to ensure the stability of the structure. In this embodiment, the number of the first weight-reducing grooves 101 is two, and the two first weight-reducing grooves 101 are arranged facing each other with respect to the central axis of the neck 200 .

The first weight-reducing groove 101 forms a downwardly opened groove on the bottom surface of the upper portion 100 of the root portion, and one side surface of the concave surface of the groove is downwardly connected to the side surface of the neck portion 200 . In this embodiment, considering the strength and weight of the components, the blade roots with different line shapes are repeatedly calculated and optimized, and finally it is determined that the connection between the concave side surface of the first weight-reducing groove 101 and the side surface of the neck 200 is symmetrical to the neck 200 . The cambered surface is concave in the direction of the surface, and then continues to transition to the lower part 300 of the root to minimize the weight of the blade root under the condition that the blade root has sufficient strength. A rounded transition is used between the top surface of the lower part 300 of the root and the side surface of the neck 200 to form the rim bearing surface 301. Under the circumstance that a certain effective contact area between the blade root and the rim is ensured, a rounded corner with a larger radius is used as much as possible. , the maximum stress borne by the rim bearing surface 301 can be better reduced. Further, the wheel rim bearing surface 301 can be formed by connecting multiple arc surfaces with different radii in sequence, which has a better effect of reducing stress compared with a single arc fillet. From the cross-sectional shape in the spanwise direction of the blade, the concave surface formed by the first weight-reducing groove 101, the side surface of the neck 200 and the envelope of the top surface of the lower part 300 of the root form a continuous arc, which has good manufacturability.

Optionally, the neck 200 is provided with a second weight reduction groove 201 , and the second weight reduction groove 201 shown in FIG. In other embodiments, the second weight-reducing groove 201 may be a groove formed on one side of the neck 200, or a groove formed on the front and rear sides of the neck 200, or a through hole, and its shape may be an oval, The number and size of polygons or other shapes are not limited here, as long as the purpose of weight reduction can be achieved while ensuring strength.

Further, in this embodiment, the top of the lower part 300 of the root is provided with an upper chamfer 302, and the bottom end of the lower part of the root 300 is provided with a lower chamfer, and the angles are both 45°. In other embodiments, the top of the lower part of the root 300 and The bottom end can be rounded, or chamfered at other angles to facilitate the installation of the rim, avoid interference, and ensure the safe operation of the unit. The line is optimized for multi-version iterative calculation.

The present invention also provides a turbine blade, comprising the above-mentioned blade root. The blade adopts enveloping weight reduction and rounded transition with low stress concentration and adjusts the amount of hood. As shown in Table 1, compared with the unimproved blade, the weight of the improved blade can be reduced from 0.8kg to 0.7kg, and the reduced weight accounts for 12.5% of the original blade weight; the maximum stress value can be reduced from 1080MPa to 753MPa, The reduced maximum stress value accounts for 30.3% of the original blade, and the optimization effect is obvious. The improved blade has good manufacturability, low weight and relatively low maximum stress, which is suitable for most turbine blades installed in the circumferential direction, which is beneficial to popularization.

Table 1

unmodified blade improved blade proportion weight 0.8kg 0.7kg 12.5% Maximum stress value 1080MPa 753MPa 30.3%

Obviously, the above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, rather than limiting the embodiments of the present invention. For those of ordinary skill in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. There is no need and cannot be exhaustive of all implementations here. Any modifications, equivalent replacements and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the claims of the present invention.

Claims (10)

1. A blade root for a turbine blade, comprising: a root upper part (100), a neck part (200) and a root lower part (300) which are connected in sequence; the root upper part (100) is used for being connected with a blade body of the turbine blade, one end of the neck part (200) is connected with the root lower part (300) in an inverted T shape, and the other end of the neck part is connected with the root upper part (100); a first weight-reducing groove (101) is formed in the upper part (100) of the root; and a fillet transition is adopted between the top surface of the lower part (300) of the root part and the side surface of the neck part (200) to form a wheel rim bearing surface.

2. Blade root of a turbine blade according to claim 1, characterised in that the neck (200) is provided with a second lightening groove (201).

3. A turbine blade root according to claim 2, characterised in that the cross-sectional shape of the second lightening slot (201) in the spanwise direction of the blade is polygonal or elliptical.

4. The turbine blade root of claim 1 wherein said rim bearing surface is formed by a plurality of successive arcuate surfaces of different radii.

5. Blade root of a turbine blade according to claim 1, characterised in that the root upper part (100) is connected to the neck (200) in a T-shape, the opening direction of the first lightening slot (101) being arranged towards the root lower part (300).

6. Blade root of a turbine blade according to claim 5, characterised in that the first lightening slot (101) has a polygonal or curved cross-sectional profile in the spanwise direction of the blade.

7. Blade root of a turbine blade according to claim 1, characterised in that the number of first lightening slots (101) is two, the two first lightening slots (101) being arranged symmetrically with respect to the central axis of the neck (200).

8. Blade root of a turbine blade according to claim 1, characterised in that the top end of the lower root part (300) is provided with an upper chamfer (302).

9. Blade root for a turbine blade according to claim 1, characterised in that the bottom end of the lower root portion (300) is provided with a lower chamfer (303).

10. A turbine blade comprising a blade body and a blade root, characterized in that the blade root is the blade root of a turbine blade according to any one of claims 1-9.

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