CN201180564Y - A turbine or steam turbine moving blade tiplet - Google Patents

Abstract

A turbine or steam turbine moving blade tiplet relates to the field of turbomachinery. The tiplet is mainly composed of a leading edge wing, a pressure surface wing, a suction surface wing and a trailing edge wing. The pressure surface wing and the suction surface wing are dynamic On the basis of the profile of the blade profile, small airfoils are expanded along the circumferential direction between the leading edge point A and the trailing edge point B of the blade shape, and the leading edge points D and C of the pressure surface and suction surface are located on the rotor blade The leading edge point A of the rotor blade or between the leading edge point A and the maximum thickness of the blade profile, the trailing edge points F and E of the pressure surface airfoil and the suction surface airfoil are located Between the thickness; both the leading edge wing and the trailing edge wing are smoothly connected with the suction surface wing and the pressure surface wing, and both the leading edge wing and the trailing edge wing are extensions of the suction surface wing and the pressure surface wing at the leading edge and the trailing edge. The utility model has the beneficial effects of reducing blade tip leakage, reducing the influence of blade tip leakage vortex and friction vortex on the flow field in the flow channel, improving the blade cascade flow field and improving the mechanical efficiency of the impeller.

Description

A turbine or steam turbine moving blade tiplet

technical field

The utility model relates to the field of impeller machinery, in particular to the design of blade tip winglets applied to moving blades of various turbines or steam turbines.

Background technique

In turbomachinery, the geometric dimension of the tip clearance between the tip of the moving blade and the casing is very small compared with the entire flow path, but it affects the flow of nearly 20% of the blade flow path, especially Smaller turbines or steam turbines, etc. The blade tip clearance has the following adverse effects: 1) The existence of the blade tip clearance will reduce the actual flow of the working fluid, resulting in a decrease in work near the blade tip, channel blockage, and increased cascade loss; The suction surface of the blade forms the tip leakage vortex, and the interaction between the tip leakage vortex and the channel vortex makes the flow in the cascade channel more complicated, the flow loss increases, and the air outlet angle is changed at the same time; 3) Since the rotor moves relative to the casing wall, The frictional movement of the boundary layer on the casing wall is caused to form a friction vortex. The three effects brought by the tip clearance all change the distribution of the flow field in the turbomachinery to varying degrees and increase the flow loss in the turbomachinery. The flow loss caused by the tip clearance and the secondary flow loss such as the tip leakage vortex and the blade tip friction vortex generally account for a considerable proportion of the total loss of the turbomachinery, resulting in an increase in the total loss of the turbomachinery. If the existing blade shroud is used, the blade shroud and the outer casing need to adopt a multiple sealing system, and the blade shroud rotates at high speed, and the centrifugal force is large, which will increase the stress of the moving blade, thereby reducing the reliability of the turbomachinery to a certain extent .

Contents of the invention

The purpose of this utility model is to provide a design of blade tip winglets applied to moving blades of various turbines or steam turbines. This design can reduce blade tip leakage and reduce the influence of blade tip leakage vortex and friction vortex on the flow field in the flow channel. , while improving the cascade flow field and improving the mechanical efficiency of the impeller.

In order to achieve the above object, the technical scheme of the utility model is as follows:

A turbine or steam turbine motor blade tiplet is mainly composed of a leading edge wing 1, a pressure surface wing 3, a suction surface wing 5, and a trailing edge wing 4 or a trailing edge wing 6; the tiplet 7 is mainly used for a turbine or a steam turbine The rotor blade 8 is installed on the top of the rotor blade, and the connection method can be processed integrally with the rotor blade, or the blade tip winglet can be processed separately, and then connected to the rotor blade by welding or other methods. The blade tip winglet 7 and the rotor blade 8 The connection and transition between them can be chamfered transition, rounded corner transition or smooth transition with free-form surface; the pressure surface wing 3 and the suction surface wing 5 can be used alone or in combination with other small wings. When used in combination, each small The airfoil can be processed integrally or separately, and then connected by welding; the pressure surface airfoil 3 and the suction surface airfoil 5 are formed on the basis of the blade profile of the moving blade, between the leading edge point A and the trailing edge point The small airfoils extending along the circumferential direction between B; the leading edge point D and the leading edge point C of the pressure surface wing 3 and the suction surface wing 5 are located at the leading edge point A of the moving blade blade or the leading edge point A and the blade shape are the largest between the thicknesses, the trailing edge point E and the trailing edge point F of the suction surface wing 5 and the pressure surface wing 3 are located between the trailing edge point B or the maximum thickness of the airfoil and the trailing edge point B, and the front edge of the suction surface wing or the pressure surface wing The optimal position of the edge point and the trailing edge point needs to be determined by calculation and experiment according to the actual demand; the width of the pressure surface wing 3 and the suction surface wing 5 from the leading edge to the trailing edge can be the same or different, and the shape can be a regular shape, It can also be an irregular shape with a free-form surface structure; The wing 6 is the extension of the suction surface wing 5 and the pressure surface wing 3 at the leading edge and the trailing edge, and generally adopts a smooth structure with a free-form surface, and the trailing edge wing can also adopt a dovetail structure. The tip of the tiplet has the same curvature as that of the outer casing to ensure a small uniform distance between the tiplet and the outer casing during operation, reducing airflow leakage from the pressure surface to the suction surface; on the tiplet The gap control between the top and the outer casing can be controlled by active gap control or passive gap control according to the design requirements, and a layer of wear-resistant coating can be applied on the inner wall of the outer casing, and wear-resistant materials can be added on the top of the tip winglet To control the leakage loss between the outer case and the tip of the tip winglet.

The beneficial effects of the utility model are: adopting the design of the blade tip winglet of the utility model at the top of the moving blades of various gas turbines or steam turbines, it has the functions of reducing the blade tip leakage and controlling the blade tip leakage vortex and friction vortex, At the same time, the secondary flow field formed by the fluid flowing from the blade root to the blade tip can be improved. Compared with the blade shroud, the utility model has the advantages of simple structure, light weight and high reliability.

Description of drawings

Fig. 1 is the top view of the utility model turbine or steam turbine motor blade and the blade tip winglet with leading edge wing and smooth structure trailing edge wing.

Fig. 2 is the top view of the utility model turbine or steam turbine moving blade and the blade tip winglet with leading edge wing and dovetail structure trailing edge wing.

Fig. 3 is a three-dimensional view of the turbine or steam turbine rotor blade and the tiplet of the utility model.

Fig. 4 is a cross-sectional view along the flow direction of the turbine or steam turbine moving blade and blade tip winglet of the present invention.

Fig. 5 is a schematic diagram of the structure of the blade tip flow field without the blade tip winglet.

Fig. 6 is a schematic diagram of the structure of the blade tip flow field with the blade tip winglet of the present invention.

In the figure: 1. Leading edge wing, 2. Blade contour line, 3. Pressure surface wing, 4. Smooth structure trailing edge wing, 5. Suction surface wing, 6. Dovetail structure trailing edge wing, 7. Tiplet winglet , 8, turbine or steam turbine blades, 9, outer casing 10, vortex 11, blade suction surface, 12, blade pressure surface.

Detailed ways

Below in conjunction with accompanying drawing, the utility model is described in further detail:

As shown in Figures 1 to 4, the turbine or steam turbine blade tiplet of the utility model is mainly composed of a leading edge wing 1, a pressure surface wing 3, a suction surface wing 5 and a smooth structure tail edge wing 4 or a dovetail structure tail edge wing 6 components, the pressure surface wing 3 and the suction surface wing 5 are small fins extending along the circumferential direction between the leading edge point A and the trailing edge point B on the basis of the blade profile of the moving blade, and the pressure surface wing 3 and the leading edge point D and leading edge point C of the suction surface airfoil 5 are located between the leading edge point A of the rotor blade profile or between the leading edge point A and the maximum thickness of the blade profile, and the trailing edge of the pressure surface airfoil 3 and the suction surface airfoil 5 The point F and the trailing edge point E are located between the trailing edge point B of the moving blade profile or between the trailing edge point B and the maximum thickness of the blade; the leading edge wing 1 and the smooth structure trailing edge wing 4 or the dovetail structure trailing edge wing 6 are all related to the suction force The airfoil 5 and the pressure airfoil 3 are smoothly connected, and the leading edge airfoil 1 and the smooth structure trailing edge airfoil 4 or the dovetail structure trailing edge airfoil 6 are extensions of the suction surface airfoil 5 and the pressure surface airfoil 3 at the leading edge and the trailing edge .

As shown in Fig. 5, in a normal tip flow field without tiplets, the high-pressure fluid on the pressure side flows to the low-pressure area on the suction side, and a friction vortex is easily formed on the pressure side. The high-speed jet fluid formed by tip clearance leakage will form a tip leakage vortex at the tip of the suction side, which may interact with the boundary layer of the end wall to form a large-area separation.

As shown in Figure 6, in the blade tip flow field using the blade tip winglet, there is a secondary flow flowing from the middle of the rotor blade to the blade tip due to the channel vortex on the pressure surface side. When the winglet is tipped, the airflow is forced to turn, which is opposite to the direction of the leakage fluid flowing from the pressure side to the suction side, and the two interact to weaken the tip leakage. increases, the frictional resistance increases, the flow rate of the leakage fluid decreases a lot, and the leakage flow decreases a lot, which also controls the influence of the leakage vortex on the suction side to a certain extent.

Claims (5)

1, a kind of turbine or steam turbine movable vane tip vane, it is characterized in that, this tip vane is mainly by the leading edge wing (1), the pressure side wing (3), the suction surface wing (5) and the trailing edge wing are formed, the pressure side wing (3) and the suction surface wing (5) are on the basis of turbine or steam turbine movable vane blade profile profile, the little fin that between blade profile leading edge point A and trailing edge point B, along the circumferential direction expands, the leading edge point D of the pressure side wing (3) and the suction surface wing (5) and leading edge point C are between movable vane blade profile leading edge point A or leading edge point A and blade profile maximum ga(u)ge, and the trailing edge point F of the pressure side wing (3) and the suction surface wing (5) and trailing edge point E are between movable vane blade profile trailing edge point B or trailing edge point B and blade profile maximum ga(u)ge; The leading edge wing (1) and the trailing edge wing all with the suction surface wing (5) and smooth connection of the pressure side wing (3), the leading edge wing (1) and the trailing edge wing all are the extensions at leading edge place and trailing edge place of the suction surface wing (5) and the pressure side wing (3).

2, a kind of turbine as claimed in claim 1 or steam turbine movable vane tip vane is characterized in that, the described trailing edge wing is the smooth structure trailing edge wing (4) or the dovetail structure trailing edge wing (6).

3, a kind of turbine as claimed in claim 1 or steam turbine movable vane tip vane, it is characterized in that, the described pressure side wing (3) and the suction surface wing (5) width along its leading edge to trailing edge is identical or different, and it is shaped as the irregularly shaped of regular shape or free form surface structure.

4, a kind of turbine as claimed in claim 1 or steam turbine movable vane tip vane is characterized in that, the Placement of described tip vane and turbine or steam turbine movable vane adopts chamfering transition, round-corner transition or adopts the free form surface smooth transition.

5, a kind of turbine as claimed in claim 1 or steam turbine movable vane tip vane is characterized in that, the described suction surface wing (5) and the pressure side wing (3) use separately or be used in combination with other winglet.

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