Heavy-duty gas turbine moving blade top cooling structure

Abstract

The invention discloses a heavy-duty gas turbine moving blade tip cooling structure, and belongs to the technical field of gas turbine design. The technical problems that due to the structure of an existing moving blade top structure of the heavy-duty gas turbine, cooling coverage is uneven, and the structural strength and the cooling efficiency are difficult to consider at the same time are solved. The blade top is arranged at the top end of the pressure side face, the groove is formed in the side, close to the blade top, of the pressure side face and comprises an upper wall face, a lower wall face and a bottom face, one end of the air film hole is formed in the lower wall face, and the other end of the air film hole communicates with the blade cavity. The bottom surface of the groove is vertically arranged; the included angle between the upper wall surface of the groove and the bottom surface of the groove is alpha which is an obtuse angle; a plurality of air film holes are uniformly formed in the lower wall surface of the groove; the distance between the upper wall surface of the groove and the top surface of the blade top is m, the total length of the blade body of the moving blade is n, and m and n meet the following formula: m / n is more than 0 and less than or equal to 1%. The cooling effect of the blade top area is improved. The method is used for gas turbine design.

Description

TECHNICAL FIELD

[0001] The application relates to a heavy gas turbine moving blade tip cooling structure and belongs to the technical field of gas turbine turbine design. BACKGROUND

[0002] The operation efficiency and service life of a heavy gas turbine directly depend on the working performance of turbine moving blades. The turbine moving blades are long-term in a high-temperature gas environment, especially in a tip area, and usually need to withstand high-temperature gas impact of 1100-1400 DEG C. The centrifugal force generated by blade rotation and the gap leakage flow disturbance between the tip and the casing easily form local thermal stress concentration, leading to thermal fatigue cracks, oxidation corrosion and even ablation failure of the tip, which becomes a key bottleneck restricting the efficiency improvement and service life extension of the heavy gas turbine.

[0003] The current moving blade tip cooling scheme of the heavy gas turbine has problems of uneven cooling coverage, difficulty in balancing the structural strength and cooling efficiency, poor processing and assembly feasibility and the like, and cannot meet the needs of the development of the heavy gas turbine in the direction of high parameters and long service life.

[0004] In summary, the existing moving blade tip structure of the heavy gas turbine has the technical problems of uneven cooling coverage and difficulty in balancing the structural strength and cooling efficiency due to its own structure. SUMMARY

[0005] The application is to solve the technical problems of uneven cooling coverage and difficulty in balancing the structural strength and cooling efficiency of the existing moving blade tip structure of the heavy gas turbine due to its own structure, and further provides a moving blade tip cooling structure of a heavy gas turbine, which comprises a tip, a pressure side, a blade cavity, a film hole and a groove. The tip is arranged at the top end of the pressure side, the groove is arranged on the side of the pressure side close to the tip, the groove comprises an upper wall, a lower wall and a bottom, one end of the film hole is arranged on the lower wall, and the other end of the film hole is in communication with the blade cavity.

[0006] The bottom of the groove is vertically arranged;

[0007] The included angle between the upper wall of the groove and the bottom of the groove is alpha, and alpha is an obtuse angle;

[0008] The film hole is uniformly arranged with a plurality of film holes on the lower wall of the groove;

[0009] The distance between the upper wall of the groove and the top surface of the tip is m, the total length size of the blade body of the moving blade is n, and the relationship between m and n satisfies the following formula:

[0010] 0 < m / n < 1%.

[0011] As another improvement of the present application, the geometric center of the groove is close to the leading edge of the pressure side, the total length size of the groove is c, the total length size from the leading edge to the trailing edge of the pressure side is d, and the relationship between c and d satisfies the following formula:

[0012] 65%≤c / d≤70%.

[0013] As another improvement of the present application, the depth size of the groove is k, and the relationship between k and n satisfies the following formula:

[0014] 1.5%≤k / n≤2%.

[0015] As another improvement of the present application, the width size of the groove is b, and the relationship between b and n satisfies the following formula:

[0016] b / n=2%.

[0017] As another improvement of the present application, the lower wall surface of the groove is perpendicular to the bottom surface of the groove.

[0018] As another improvement of the present application, the angle between the gas film hole and the lower wall surface is β; β is an obtuse angle.

[0019] As another improvement of the present application, the angle α between the upper wall surface of the groove and the bottom surface of the groove is equal to the angle β between the gas film hole and the lower wall surface.

[0020] As another improvement of the present application, it further comprises a suction side surface arranged on the suction side of the blade.

[0021] As another improvement of the present application, the number of gas film holes is 20 to 25.

[0022] As another improvement of the present application, the distance between adjacent gas film holes is a, and the diameter of the gas film hole is r, and the values of a and r can be adjusted according to the number of gas film holes.

[0023] Advantages of the present application:

[0024] The present application utilizes a groove with a gas film hole arranged on the pressure side of the blade, which can guide the cooling gas to the vicinity of the blade tip through the groove. The high-pressure cooling gas increases the resistance of the tip clearance leakage flow during the operation of the gas turbine, reduces the main gas leakage amount of the tip clearance, and in addition, the cooling gas covers the tip area, improves the cooling effect of the tip area, and makes the blade temperature distribution more uniform. The groove is set at a specific position and has a special shape, which not only avoids the stress concentration area of the blade, but also ensures that the cooling gas introduced by the subsequent gas film hole can cover the key heat exchange parts of the blade tip in the largest range. At the same time, compared with the prior art, the present application is easier to implement in engineering application and has lower cost. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1It is a whole structure schematic diagram of a heavy-duty gas turbine moving blade tip cooling structure of the present application.

[0026] Figure 2 It is a sectional view comparison schematic diagram of the structure of the present application and the prior art.

[0027] Figure 3 It is Figure 2 It is a partial sectional view schematic diagram of a heavy-duty gas turbine moving blade tip cooling structure of the present application.

[0028] Figure 4 It is a sectional view schematic diagram of a groove of a heavy-duty gas turbine moving blade tip cooling structure of the present application. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the examples of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments of the present application, all the embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0030] DETAILED DESCRIPTION Figures 1 to 4 In this embodiment, a heavy-duty gas turbine moving blade tip cooling structure includes a tip 7, a pressure side 5, a blade cavity 8, a film hole 3 and a groove 2. The tip 7 is arranged at the top end of the pressure side 5, and the groove 2 is arranged on the side of the pressure side 5 close to the tip 7. The groove 2 includes an upper wall 1, a lower wall 4 and a bottom surface. One end of the film hole 3 is arranged on the lower wall 4, and the other end of the film hole 3 is in communication with the blade cavity 8.

[0031] The bottom surface of the groove 2 is arranged vertically;

[0032] The included angle between the upper wall 1 of the groove 2 and the bottom surface of the groove 2 is α, and α is an obtuse angle;

[0033] The film hole 3 is uniformly arranged on the lower wall 4 of the groove 2;

[0034] The distance between the upper wall 1 of the groove 2 and the top surface of the tip 7 is m, the total length of the blade body of the moving blade is n, and the relationship between m and n satisfies the following formula:

[0035] 0 < m / n ≤ 1%.

[0036] The cooling gas introduced from the film hole 3 can increase the pressure of the tip gap through the upper wall surface 1, effectively reducing the leakage of the tip main flow, and improving the efficiency of the engine unit. The groove 2 is the key basic structure of the cooling configuration, and the slotting position, size parameter and angle design of the groove directly affect the cooling effect and the running stability of the blade. The groove is set at a specific position and has a special shape, which not only avoids the stress concentration area of the blade, but also ensures that the cooling gas introduced from the subsequent film hole can cover the key heat exchange parts of the tip in the maximum range.

[0037] The embodiment utilizes the groove with the film hole arranged on the pressure side of the blade, and the cooling gas can be introduced to the tip through the groove. The high-pressure cooling gas increases the resistance of the tip gap leakage flow during the operation of the engine, reduces the leakage amount of the tip gap main gas, and further covers the tip area, improves the cooling effect of the tip area, and makes the blade temperature distribution more uniform. Meanwhile, compared with the prior art, the present application is easier to implement in engineering application and has lower cost.

[0038] Specific embodiment two: in combination with Figures 1 to 4 The embodiment is described, and the difference between the embodiment and the specific embodiment one is that the geometric center of the groove 2 is close to the leading edge of the pressure side 5, the total length size of the groove 2 is c, the total length size from the leading edge to the trailing edge of the pressure side 5 is d, and the relationship between c and d satisfies the following formula:

[0039] 65%≤c / d≤70%.

[0040] In this way, the groove not only avoids the stress concentration area of the blade, but also ensures that the cooling gas introduced from the subsequent film hole can cover the key heat exchange parts of the tip in the maximum range. The other components and connection modes are the same as those of the specific embodiment one.

[0041] Specific embodiment three: in combination with Figures 1 to 4 The embodiment is described, and the difference between the embodiment and the specific embodiment one is that the depth size of the groove 2 is k, and the relationship between k and n satisfies the following formula:

[0042] 1.5%≤k / n≤2%.

[0043] In this way, the groove not only avoids the stress concentration area of the blade, but also ensures that the cooling gas introduced from the subsequent film hole can cover the key heat exchange parts of the tip in the maximum range. The other components and connection modes are the same as those of the specific embodiment one or two.

[0044] Specific embodiment four: in combination with Figures 1 to 4 The embodiment is described, and the difference between the embodiment and the specific embodiment one is that the width size of the groove 2 is b, and the relationship between b and n satisfies the following formula:

[0045] b / n=2%.

[0046] In this way, the groove avoids the stress concentration area of the blade, and ensures that the cooling air introduced by the subsequent film holes can cover the key heat exchange parts of the blade tip in the largest range. The other components and connection manners are the same as any one of the first to third embodiments.

[0047] Embodiment five: in combination Figures 1 to 4 In this embodiment, the difference from the first embodiment is that the lower wall surface 4 of the groove 2 is perpendicular to the bottom surface of the groove 2. In this way, the groove avoids the stress concentration area of the blade, and ensures that the cooling air introduced by the subsequent film holes can cover the key heat exchange parts of the blade tip in the largest range. The other components and connection manners are the same as any one of the first to fourth embodiments.

[0048] Embodiment six: in combination Figures 1 to 4 In this embodiment, the difference from the first embodiment is that the angle between the film hole 3 and the lower wall surface 4 is β; β is an obtuse angle. In this way, the groove avoids the stress concentration area of the blade, and ensures that the cooling air introduced by the subsequent film holes can cover the key heat exchange parts of the blade tip in the largest range. The other components and connection manners are the same as any one of the first to fifth embodiments.

[0049] Embodiment seven: in combination Figures 1 to 4 In this embodiment, the difference from the first embodiment is that the angle α between the upper wall surface 1 of the groove 2 and the bottom surface of the groove 2 is equal to the angle β between the film hole 3 and the lower wall surface 4. The function is to improve the cooling effect. The other components and connection manners are the same as any one of the first to sixth embodiments.

[0050] Embodiment eight: in combination Figures 1 to 4 In this embodiment, the difference from the first embodiment is that the embodiment further includes a suction side surface arranged on the suction side of the blade. The other components and connection manners are the same as any one of the first to seventh embodiments.

[0051] Embodiment nine: in combination Figures 1 to 4 In this embodiment, the difference from the first embodiment is that the number of film holes 3 is 20 to 25. Too many film holes will affect the strength of the blade, and too few film holes will not achieve the expected cooling effect. Therefore, the number of film holes has a clear impact on the implementation effect of this embodiment. Through research, for some heavy gas turbine blades in the embodiments, the number of film holes is between 20 and 25, which can make the cooling effect and the strength of the blade body of this embodiment be taken into account. The other components and connection manners are the same as any one of the first to eighth embodiments.

[0052] Embodiment ten: in combinationFigures 1 to 4 The embodiment is different from the first embodiment in that the distance between adjacent air film holes 3 is a, and the diameter of the air film hole 3 is r, and the values of a and r can be adjusted according to the number of air film holes 3. The other components and connection modes are the same as any one of the first to ninth embodiments.

[0053] In combination ​ The working principle of the present application is explained as follows:

[0054] The present application uses a groove with air film holes arranged on the pressure side of the blade to guide the cooling air to the vicinity of the blade tip through the groove. The high-pressure cooling air increases the resistance of the tip clearance leakage flow during the operation of the gas turbine, and reduces the main gas leakage amount of the tip clearance. In addition, the cooling air covers the tip region, improves the cooling effect of the tip region, and makes the temperature distribution of the blade more uniform. The groove is set at a specific position and has a special shape, which not only avoids the stress concentration area of the blade, but also ensures that the cooling air introduced by the subsequent air film holes can cover the key heat exchange parts of the blade tip in the maximum range.

[0055] The above embodiments are only used to illustrate the technical solutions of the present application, but not to limit it; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A heavy-duty gas turbine moving blade tip end cooling structure, characterized by It includes a blade tip (7), a pressure side (5), a blade cavity (8), a film hole (3) and a groove (2); the blade tip (7) is arranged at the top end of the pressure side (5), the groove (2) is arranged on the side of the pressure side (5) close to the blade tip (7), the groove (2) comprises an upper wall (1), a lower wall (4) and a bottom, one end of the film hole (3) is arranged on the lower wall (4), and the other end of the film hole (3) is communicated with the blade cavity (8); The bottom of the groove (2) is arranged vertically; The included angle between the upper wall (1) of the groove (2) and the bottom of the groove (2) is α, and α is an obtuse angle; The film hole (3) is uniformly arranged on the lower wall (4) of the groove (2); The distance between the upper wall (1) of the groove (2) and the top surface of the blade tip (7) is m, the total length of the blade body of the moving blade is n, and the relationship between m and n satisfies the following formula: 0 < m / n ≤ 1%.

2. A heavy-duty gas turbine moving blade tip end cooling structure according to claim 1, characterized by The geometric center position of the groove (2) is close to the leading edge of the pressure side (5), the total length of the groove (2) is c, the total length from the leading edge to the trailing edge of the pressure side (5) is d, and the relationship between c and d satisfies the following formula: 65% ≤ c / d ≤ 70%.

3. A heavy duty gas turbine vane tip cooling structure according to claim 1, wherein The depth of the groove (2) is k, and the relationship between k and n satisfies the following formula: 1.5% ≤ k / n ≤ 2%.

4. A heavy duty gas turbine vane tip cooling structure according to claim 1, wherein The width of the groove (2) is b, and the relationship between b and n satisfies the following formula: b / n = 2%.

5. A heavy duty gas turbine vane tip cooling structure according to claim 1, wherein The lower wall (4) of the groove (2) is perpendicular to the bottom of the groove (2).

6. A heavy-duty gas turbine vane tip cooling structure according to claim 5, wherein The included angle between the film hole (3) and the lower wall (4) is β; β is an obtuse angle.

7. A heavy-duty gas turbine vane tip cooling structure according to claim 6, wherein The included angle α between the upper wall (1) of the groove (2) and the bottom of the groove (2) is equal to the included angle β between the film hole (3) and the lower wall (4).

8. A heavy duty gas turbine vane tip cooling structure according to claim 1, wherein It also includes a suction side, and the suction side is arranged on the suction side of the moving blade.

9. A heavy-duty gas turbine vane tip cooling structure according to claim 1, wherein The number of the film holes (3) is 20 to 25.

10. A heavy-duty gas turbine vane tip cooling structure according to claim 9, wherein The distance between adjacent film holes (3) is a, and the diameter of the film hole (3) is r, and the values of a and r can be adjusted according to the number of the film holes (3). The distance between adjacent film holes (3) is a, and the diameter of the film hole (3) is r, and the values of a and r can be adjusted according to the number of the film holes (3).

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