CN101255800B - Turbine or steam turbine rotor blade tip winglet - Google Patents

Abstract

Turbine or steam turbine moving blade tiplets relate to the field of turbomachinery. The tiplets are mainly composed of leading edge wings, pressure surface wings, suction surface wings and trailing edge wings. The pressure surface wings and suction surface wings are on the rotor blade Based on the profile of the rotor blade, the small airfoils are extended along the circumferential direction between the leading edge point A and the trailing edge point B, and the leading edge points D and C of the pressure surface and suction surface are located in front of the rotor blade Between edge point A or leading edge point A and the maximum thickness of the blade profile, trailing edge points F and E of the pressure surface and suction surface are located between the trailing edge point B of the rotor blade profile or between the trailing edge point B and the maximum thickness of the blade profile 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 invention 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 increasing the mechanical efficiency of the impeller.

Description

Turbine or steam turbine rotor blade tip winglet

technical field

The invention relates to the field of turbomachinery, in particular to the design of tiplets 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 the present invention is to provide a design of blade tip winglets applied to moving blades such as various turbines or steam turbines, which can reduce blade tip leakage and reduce the impact of blade tip leakage vortex and friction vortex on the flow field in the flow channel. At the same time, the cascade flow field is improved and the mechanical efficiency of the impeller is improved.

In order to achieve the above object, technical scheme of the present invention is as follows:

Turbine or steam turbine moving blade tiplet is mainly composed of leading edge wing 1, pressure surface wing 3, suction surface wing 5 and trailing edge wing 4 or trailing edge wing 6; tiplet 7 is mainly used for turbine or steam turbine moving blade 8. It is installed on the top of the rotor blade. 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 gap between the blade tip winglet 7 and the rotor blade 8 The connection transition can be chamfered transition, rounded 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 winglets. When used in combination, each winglet can It can be processed in one piece, or can be processed separately, and then connected by welding; The small airfoils extending along the circumferential direction; the leading edge point D and the leading edge point C of the pressure surface airfoil 3 and the suction surface airfoil 5 are located at the leading edge point A of the blade profile or between the leading edge point A and the maximum thickness of the blade profile Between, the trailing edge point E and the trailing edge point F of the suction surface airfoil 5 and the pressure surface airfoil 3 are located between the trailing edge point B or the maximum thickness of the airfoil and the trailing edge point B, and the leading edge point of the suction surface airfoil or the pressure surface airfoil The optimal position of 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 shapes can be regular shapes or It is an irregular shape with a free-form surface structure; the leading edge wing 1 and the trailing edge wing 4 or the trailing edge wing 6 are smoothly connected with the suction surface wing 5 and the pressure surface wing 3, and the leading edge wing 1 and the trailing edge wing 4 or the trailing edge wing 6 are connected smoothly. It 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 effect of the present invention is: adopt the design of blade tip winglet of the present invention at the top of moving blade of the turbine of various gas turbines or steam turbine, have the effect of reducing blade tip leakage, controlling blade tip leakage vortex and friction vortex, can simultaneously The secondary flow field formed by the flow of fluid from the blade root to the blade tip is improved, and the invention has the advantages of simple structure, light weight and high reliability compared with the blade shroud.

Description of drawings

Figure 1 is a top view of a turbine or steam turbine rotor blade and a tiplet with a leading edge wing and a smooth structured trailing edge wing of the present invention.

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

Figure 3 is a three-dimensional view of a turbine or steam turbine blade and tiplet of the present invention.

Fig. 4 is a sectional view along the flow direction of the turbine or steam turbine moving blade and the tiplet 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 of 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.

Detailed ways

The present invention is described in further detail below in conjunction with accompanying drawing:

As shown in Figures 1 to 4, the turbine or steam turbine blade tiplet of the present invention is mainly composed of leading edge wing 1, pressure surface wing 3, suction surface wing 5 and smooth structure trailing edge wing 4 or dovetail structure trailing edge wing 6 Composition, the pressure surface wing 3 and the suction surface wing 5 are small fins extending in 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, the pressure surface wing 3 The leading edge point D and the 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 airfoil, and the trailing edge points of the pressure surface airfoil 3 and the suction surface airfoil 5 F and trailing edge point E are located between trailing edge point B or trailing edge point B and the maximum thickness of the blade profile; leading edge wing 1 and smooth structure trailing edge wing 4 or dovetail structure trailing edge wing 6 are all connected to the suction surface The wing 5 and the pressure surface wing 3 are smoothly connected, and the leading edge wing 1 and the smooth structure trailing edge wing 4 or the dovetail structure trailing edge wing 6 are extensions of the suction surface wing 5 and the pressure surface wing 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 (4)

1. turbine rotor blade leaf winglet, it is characterized in that, this tip vane is 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 rotor blade blade profile profile, the little fin that between movable vane 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 leading edge point (C) of the suction surface wing (5) are positioned between movable vane blade profile leading edge point (A) or leading edge point (A) and the blade profile maximum ga(u)ge, and the trailing edge point (F) of the pressure side wing (3) and the trailing edge point (E) of the suction surface wing (5) are positioned between movable vane blade profile trailing edge point (B) or trailing edge point (B) and the 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. turbine rotor blade tip vane as claimed in claim 1 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. turbine rotor blade tip vane as claimed in claim 1 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.

4. turbine rotor blade tip vane as claimed in claim 1 is characterized in that, the described suction surface wing (5) and the pressure side wing (3) uses separately or other winglet is used in combination.

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