Blade crown damping single-crystal turbine cooling blade for gas turbine

Abstract

The invention aims to provide a blade crown damping single crystal turbine cooling blade for a gas turbine, which belongs to the field of gas turbines and comprises a blade crown, a blade body, a margin plate and a tenon root, the blade crown, the blade body, the margin plate and the tenon root are arranged from top to bottom, three air seal teeth are arranged at the top of the blade crown, and the tenon root is of a longitudinal tree structure formed by four rows of tenon teeth. When a single crystal material is used, the top of the blade is provided with a blade crown structure, the flow loss of the blade top is effectively reduced, the working efficiency of a turbine is improved, meanwhile, the parallel blade crown has a vibration damping effect, and the possibility that the blade is damaged under vibration stress is reduced; mature fir-tree-shaped tenon teeth are adopted as connecting structures between the blades and the wheel disc, and the working reliability of the tenon teeth is improved. A multi-channel cooling structure is adopted in the blade for cooling the blade, and the surface working temperature of the blade is effectively reduced. The blade crown damping single-crystal turbine cooling blade can work reliably for a long time in a high-temperature environment.

Description

Technical Field

[0001] The present invention relates to a gas turbine, in particular to a turbine blade. Background Art

[0002] Gas turbines are high-end equipment widely used in the power equipment and energy fields. Their design and manufacturing difficulty is at the top level of the manufacturing industry. Turbine blades are key components of gas turbines. Their harsh working environment such as high temperature and high pressure makes them difficult to design and manufacture, and their failure rate is high, which has a crucial impact on the reliability of gas turbines.

[0003] At present, gas turbine turbine cooling blades are developing towards high temperature resistance levels. Due to international technological blockades, the design and manufacture of gas turbine cooling blades are often usually achieved through self-development. Summary of the invention

[0004] The object of the present invention is to provide a single crystal turbine cooling blade with blade crown damping for a gas turbine, which can make the working gap between the blade top and the honeycomb seal very small, reduce the flow loss at the blade top, and improve the working efficiency of the turbine.

[0005] The object of the present invention is achieved in that:

[0006] The present invention discloses a blade crown damping single crystal turbine cooling blade for a gas turbine, which is characterized in that it comprises a blade crown, a blade body, an edge plate and a tenon root. The blade crown, the blade body, the edge plate and the tenon root are arranged from top to bottom. Three air sealing teeth are arranged on the top of the blade crown, and the tenon root is a longitudinal tree-shaped structure composed of four rows of tenon teeth.

[0007] The present invention may also include:

[0008] 1. A rectangular window is set on the exhaust side of the blade body, and three cooling channels are formed inside the blade body, edge plate and tenon root: the cooling air enters from one side end of the tenon root, flows radially into the blade body, turns 90° and is discharged from the rectangular window to form the first cooling channel; the cooling air enters from the middle of the tenon root, flows radially into the blade body, turns two 180° and is discharged from the rectangular window to form the second cooling channel; the cooling air enters from the other end of the tenon root and mixes with the cooling air in the second cooling channel to form the third cooling channel.

[0009] 2. The first cooling channel and the second cooling channel are designed with flow ribs to enhance heat exchange. The first cooling channel and the second cooling channel are connected by two holes with a diameter of 1.5 mm at the blade part.

[0010] 3. A throttle hole with a diameter of 4 mm is designed on the third cooling channel.

[0011] 4. Two rows of 1.2mm diameter flow column structures are designed on the exhaust side of the blade.

[0012] 5. The blade crown is a parallel crown, and the angle between the working surface of the parallel crown and the engine axis is 30° to 35°.

[0013] 6. The three air seal teeth are in the shape of comb teeth and have the same outer diameter structure.

[0014] 7. The blade crown, blade body, edge plate and tenon root are made of single crystal material and are grown from one grain.

[0015] The advantages of the present invention are as follows: the single crystal material improves the temperature resistance level of the blade, and can increase the life of the blade at the same operating temperature; while using the single crystal material, the top of the blade is provided with a blade crown structure, which effectively reduces the flow loss at the blade tip and improves the working efficiency of the turbine. At the same time, the parallel blade crown itself has a vibration damping effect, which reduces the possibility of the blade being damaged under vibration stress; the mature fir-tree-shaped tenon is used as the connection structure between the blade and the wheel disc, which improves the working reliability of the tenon. A multi-channel cooling structure is used inside the blade for blade cooling, which effectively reduces the working temperature of the blade surface. The blade crown damping single crystal turbine cooling blade of the present invention can work reliably for a long time in a high temperature environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the appearance structure of the present invention;

[0017] Figure 2 This is a schematic diagram of a flat crown of a leaf;

[0018] Figure 3 It is a schematic diagram of the cross section of the blade body;

[0019] Figure 4 It is a schematic diagram of the cooling structure of the blade inner cavity;

[0020] Figure 5 This is a schematic diagram of blade cooling flow;

[0021] Figure 6 Schematic diagram of blade vibration damping. DETAILED DESCRIPTION

[0022] The present invention is described in more detail below with reference to the accompanying drawings:

[0023] Combination Figure 1-6 The present invention is a single crystal turbine cooling blade with blade crown damping for gas turbines. Its appearance is shown in the figure. The blade is made of single crystal material. The whole blade is grown from one grain. It has the characteristics of higher temperature resistance than equiaxed crystal and better mechanical properties than equiaxed crystal material at the same temperature. The blade consists of four parts: blade crown, blade body, edge plate and tenon root. The inside of the blade has an optimized cooling structure, and the cooling channel mainly consists of three flow paths.

[0024] The external structure of the cooling blade of the present invention is as follows Figure 1 As shown in the figure, the blade crown is a parallel crown, that is, one side of the blade crown is parallel to the other side of the adjacent blade crown. After the whole circle is assembled, there is a designed gap between the flat crowns, which can offset the elongation of the blade crown caused by thermal expansion in the working state. At the same time, the small gap between the blade crowns plays a vibration damping role. There are three gas seal teeth on the top of the blade crown to reduce gas leakage and improve the working efficiency of the turbine. The three gas seal teeth are of equal outer diameter structure. When working, the gas pressure at the blade tip gradually decreases from the first tooth to the third tooth. The tenon root of the blade is a fir tree-shaped structure with four pairs of eight working surfaces. In the working state, the four pairs of tenons work in combination with the corresponding mating surfaces of the wheel to jointly bear the stress of the working blade under the action of centrifugal load, aerodynamic load and thermal load.

[0025] like Figure 2 The angle between the flat crown of the cooling blade of the present invention and the axis of the engine is 30° to 35°, preferably 33°. Figure 3 The figure shows the cross section of the cooling blade of the present invention, and the width of the gap at the exhaust edge is 0.7 mm.

[0026] The internal cooling structure of the cooling blade of the present invention is as follows Figure 4 As shown, the cooling structure has three-channel characteristics. The first channel is located in the leading edge area of ​​the blade and the upper part of the blade body, with a 90° turning feature. The second channel is located in the middle of the blade body and has two 180° turning features. The third channel is located at the lower part of the exhaust side of the blade body. The first channel and the second channel are designed with flow ribs to enhance heat exchange. The first channel and the second channel are connected by two holes with a diameter of 1.5mm in the blade body. The third channel is designed with a 4mm diameter throttle hole. Two rows of flow column structures with a diameter of 1.2mm are designed on the exhaust side. The cold air outlet on the exhaust side is 23 rectangular, and the rectangular size is 1.6mm×0.7mm.

[0027] The cooling scheme implementation method of the cooling blade of the present invention is as follows Figure 5As shown, the internal cooling structure is mainly divided into three channels. The first cooling channel is L-shaped and is used to cool the leading edge and upper part of the blade. The cooling air flows into the inside of the blade from the inlet 1 and flows radially along the blade into the leading edge channel of the blade shown in the cavity 1. After heat exchange in the leading edge channel with the flow rib structure for enhancing heat exchange, the cooling air turns 90° and enters the upper area of ​​the blade. After heat exchange, it enters the cylindrical flow column at the exhaust edge of the blade and is finally discharged from the rectangular window at the exhaust edge of the upper part of the blade. The second cooling channel is a serpentine cooling channel, which is used to cool the middle area of ​​the blade body. The cold air flows into the inside of the blade from the inlet 2 and flows radially along the blade into the serpentine channel shown in the cavity 2. The serpentine channel is provided with oblique flow ribs to enhance heat exchange. After turning 360° through the serpentine channel, the cooling air enters the flow column at the trailing edge and finally flows out through the rectangular window at the exhaust edge. The third cooling channel is used to compensate for other areas of the blade that are not covered by the second cooling channel. The cooling air enters the inside of the blade from the inlet 3 and mixes with the cooling air of the second cooling channel. Finally, it enters the flow column at the exhaust edge of the blade and flows out through the rectangular window at the exhaust edge.

[0028] Combination Figure 6 The vibration damping effect of the cooling blade of the present invention is explained. Figure 6 a represents the blade in the assembled state, with a small parallel working gap between the blade crowns. Figure 6 b represents the first-order vibration mode of the blade when the blade crown does not play a damping role. At this time, since the blade crown has no constraints, the blade produces a large vibration amplitude, which may bring vibration stress exceeding the design value. Figure 6 C indicates that the blade crown has a damping effect, that is, the first-order vibration mode of the blade of the present invention under the actual working state. At this time, the parallel blade crown limits the vibration amplitude of the blade and can effectively reduce the vibration stress of the blade.

Claims

1. A single crystal turbine cooling blade with shroud damping for a gas turbine, characterized in that: It includes a blade crown, a blade body, a lip plate and a tenon root. From top to bottom, three air-sealing teeth are arranged on the top of the blade crown, and the tenon root is a longitudinal tree-shaped structure composed of four teams of tenon teeth.

2. The single crystal turbine cooling blade with shroud damping for a gas turbine according to claim 1, characterized in that: A rectangular window is set on the exhaust edge of the blade body, and three cooling channels are formed inside the blade body, edge plate and tenon: the cooling air enters from one side end of the tenon root, flows radially into the blade body, turns 90° and is discharged from the rectangular window to form the first cooling channel; the cooling air enters from the middle of the tenon root, flows radially into the blade body, turns two 180° and is discharged from the rectangular window to form the second cooling channel; the cooling air enters from the other end of the tenon root and mixes with the cooling air in the second cooling channel to form the third cooling channel.

3. The single crystal turbine cooling blade with shroud damping for a gas turbine according to claim 2, characterized in that: The first cooling channel and the second cooling channel are designed with flow ribs for enhancing heat exchange, and the first cooling channel and the second cooling channel are connected by two holes with a diameter of 1.5 mm at the blade part.

4. The single crystal turbine cooling blade with shroud damping for a gas turbine according to claim 2, characterized in that: The third cooling channel is designed with a throttle hole with a diameter of 4 mm.

5. The single crystal turbine cooling blade with shroud damping for a gas turbine according to claim 2, characterized in that: The exhaust side of the blade is designed with two rows of flow columns with a diameter of 1.2 mm.

6. The single crystal turbine cooling blade with shroud damping for a gas turbine according to claim 1, characterized in that: The blade crown is a parallel crown, and the angle between the working surface of the parallel crown and the engine axis is 30° to 35°.

7. The single crystal turbine cooling blade with shroud damping for a gas turbine according to claim 1, characterized in that: The three air seal teeth are in the shape of comb teeth and have the same outer diameter structure.

8. The single crystal turbine cooling blade with shroud damping for a gas turbine according to claim 1, characterized in that: The blade crown, blade body, edge plate and tenon root are made of single crystal material and are grown from one grain.

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