Blade top cooling structure of turbine blade and gas turbine

Abstract

The invention discloses a turbine blade tip cooling structure and a gas turbine, the turbine blade is provided with a cavity, the bottom wall of the turbine blade is provided with a cold air through hole, the cold air through hole is communicated with the cavity to introduce cooling gas, impact plates are arranged in the lower direction of a top plate of the turbine blade at intervals, and the impact plates are provided with impact holes penetrating up and down. An air film hole is formed in the top plate. According to the blade top cooling structure of the turbine blade, the impact plate is arranged at the blade top, impact cooling of the top plate is achieved through the impact holes in the impact plate, combination of impact cooling and air film cooling can be achieved in cooperation with the air film holes formed in the top plate, the blade top cooling effect is improved, a local high-temperature area of the blade top is eliminated, and the service life of the blade top is prolonged. And the temperature uniformity of the blade top area is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of turbine equipment, and in particular to a blade tip cooling structure of a turbine blade and a gas turbine. Background Art

[0002] With the continuous improvement of the comprehensive performance of gas turbines, the inlet temperature of gas turbine blades is getting higher and higher. The harsh working environment has made the cooling problem of turbine blades more and more concerned.

[0003] In order to adapt the gas turbine blades to higher operating temperatures and ensure their safe and stable operation, it is necessary to improve the cooling structure of the turbine blades to improve the cooling effect of the turbine blades. When cooling the turbine blades, due to the complex flow structure in the gap at the top of the turbine blades, the cooling of the blade tops is difficult. Currently, the tops of the turbine blades are mostly cooled by simple internal convection plus air film cooling, which has a poor cooling effect and is prone to local high temperature areas. Summary of the invention

[0004] The technical problem to be solved by the present invention is that, in view of the defects and shortcomings of the prior art, a blade tip cooling structure for a turbine blade is proposed, in which an impact plate is arranged at the blade tip, and impact cooling of the top plate is achieved by using the impact holes on the impact plate. In combination with the film holes arranged on the top plate, the impact cooling and film cooling can be combined, thereby improving the cooling effect of the blade tip, eliminating the local high temperature area on the blade tip, and improving the temperature uniformity of the blade tip area.

[0005] The blade tip cooling structure of the turbine blade in an embodiment of the present invention, the turbine blade has a cavity, a cooling air through hole is provided on the bottom wall of the turbine blade, the cooling air through hole is connected to the cavity to allow cooling air to pass through, an impact plate is arranged at a distance below the top plate of the turbine blade, the impact plate is provided with impact holes running through from top to bottom, and the top plate is provided with air film holes.

[0006] The tip cooling structure of the turbine blade of the embodiment of the present invention is characterized in that an impact plate is arranged at a certain distance below the top plate of the turbine blade, and the impact plate is provided with impact holes penetrating up and down, and the top plate is provided with film holes, thereby, cold air can be sprayed toward the top plate through the impact holes to form impact cooling, and the film holes provided on the top plate can realize the combination of impact cooling and film cooling, thereby improving the cooling effect of the blade tip, eliminating the local high temperature area of ​​the blade tip, and improving the temperature uniformity of the blade tip area.

[0007] In some embodiments, a vertically arranged partition is connected between the impact plate and the top plate.

[0008] In some embodiments, there are multiple baffles, and the multiple baffles are arranged at intervals along a first direction, and the first direction is the direction from the leading edge of the turbine blade to the trailing edge of the turbine blade. A partition cavity is formed between adjacent baffles and between the baffle and the turbine blade, and any of the partition cavities has corresponding impact holes and air film holes.

[0009] In some embodiments, there are a plurality of air film holes, and the arrangement density of the air film holes in a region adjacent to a leading edge of a turbine blade is greater than the arrangement density of the air film holes in a region adjacent to a trailing edge of a turbine blade.

[0010] In some embodiments, the impact plate is a plurality of impact plates arranged at intervals in the height direction of the turbine blade.

[0011] In some embodiments, the orthographic projection of the air film hole on the impact plate does not overlap with the impact hole.

[0012] In some embodiments, protrusions or recesses arranged at intervals are provided on the side of the top plate facing the impact plate.

[0013] In some embodiments, the height S of the protrusion satisfies 0.4 mm≤S≤0.6 mm; and / or the depth D of the pit satisfies 0.3 mm≤D≤0.5 mm.

[0014] In some embodiments, a diameter d of the impact hole satisfies 0.4 mm ≤ d ≤ 0.8 mm.

[0015] In some embodiments, a distance H between the impact plate and the top plate satisfies 1.5d≤H≤3.5d.

[0016] The gas turbine of the embodiment of the present invention includes the blade tip cooling structure of the turbine blade described in the above embodiment.

[0017] The gas turbine of the embodiment of the present invention adopts the blade tip cooling structure of the turbine blade, and an impact plate is arranged at a distance below the top plate of the turbine blade. The impact plate is provided with impact holes penetrating up and down, and the top plate is provided with film holes. Therefore, cold air can be sprayed toward the top plate through the impact holes to form impact cooling. The film holes provided on the top plate can realize the combination of impact cooling and film cooling, thereby improving the blade tip cooling effect, eliminating the local high temperature area of ​​the blade tip, and improving the temperature uniformity of the blade tip area. The gas turbine has good performance and a long practical life. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 1 is a top view of a blade tip cooling structure of a turbine blade according to an embodiment of the present invention.

[0019] Figure 24 is a cross-sectional view of a blade tip cooling structure of a turbine blade according to an embodiment of the present invention.

[0020] Figure 3 4 is a cross-sectional view of a tip cooling structure of a turbine blade according to an embodiment of the present invention, showing the recesses arranged on the top plate.

[0021] Figure 4 is a cross-sectional view of a blade tip cooling structure of a turbine blade according to an embodiment of the present invention, wherein a projection arranged on the top plate is shown.

[0022] Reference numerals:

[0023] Turbine blade 1, top plate 2, air film hole 21, pit 22, protrusion 23, impact plate 3, impact hole 31, partition plate 4. DETAILED DESCRIPTION

[0024] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0025] like Figure 1 As shown, the blade tip cooling structure of the turbine blade of an embodiment of the present invention, the turbine blade 1 has a cavity, a cooling air through hole is provided on the bottom wall of the turbine blade 1, the cooling air through hole is connected to the cavity to allow cooling air to pass through, an impact plate 3 is arranged at a distance below the top plate 2 of the turbine blade 1, the impact plate 3 is provided with an impact hole 31 penetrating from top to bottom, and the top plate 2 is provided with an air film hole 21.

[0026] It can be understood that after the cold air is introduced into the cavity through the cold air through the hole, the cold air is sprayed and impacted toward the top plate 2 through the impact hole 31, thereby increasing the convection coefficient of the inner wall of the top plate 2 and improving the cooling effect of the top plate 2. In addition, the cold air that impacts the top plate 2 will also flow through the film holes 21 on the top plate 2 to form a cooling airflow covering the surface of the top plate 2, thereby forming impact cooling and film cooling on the top plate 2 at the same time, thereby improving the cooling effect of the blade tip.

[0027] In the blade tip cooling structure of the turbine blade in the embodiment of the present invention, an impact plate 3 is arranged at a certain distance below the top plate 2 of the turbine blade 1, and an impact hole 31 is provided on the impact plate 3 which passes through the top plate 2, and an air film hole 21 is provided on the top plate 2. Therefore, cold air can be sprayed toward the top plate 2 through the impact hole 31 to form impact cooling. In combination with the air film hole 21 provided on the top plate 2, the impact cooling and air film cooling can be combined, thereby improving the blade tip cooling effect, eliminating the local high temperature area on the blade tip, and improving the temperature uniformity of the blade tip area.

[0028] In some implementations, a vertically arranged partition 4 is connected between the impact plate 3 and the top plate 2. That is, an impact cavity can be formed between the impact plate 3 and the top plate 2, and the partition 4 is arranged in the impact cavity and divides the impact cavity into a plurality of independent sub-cavities, thereby weakening the influence of the cross flow on the impact effect.

[0029] Specifically, there are multiple partitions 4, and the multiple partitions 4 are arranged at intervals along a first direction, and the first direction is the direction from the leading edge of the turbine blade to the trailing edge of the turbine blade. A partition cavity is formed between adjacent partitions 4 and between the partition 4 and the turbine blade 1, and any partition cavity has corresponding impact holes 31 and air film holes 21.

[0030] Preferably, there are multiple film holes 21, and the density of the film holes 21 in the area adjacent to the leading edge of the turbine blade is greater than the density of the film holes 21 in the area adjacent to the trailing edge of the turbine blade. It should be noted that the temperatures of different areas of the top plate 2 are not the same, and the temperature of the leading edge area is higher than that of the trailing edge area. Therefore, the design of high-density film holes 21 at the leading edge position can effectively cool the high-temperature area, thereby balancing the cooling effect of each position of the top plate 2 and improving the temperature uniformity of the blade tip area.

[0031] Furthermore, based on the different heat exchange systems at different positions of the top plate 2, there are multiple impact holes 31, and the layout density of the impact holes 31 is consistent with the layout trend of the air film holes 21, that is, the front edge area is arranged with high density.

[0032] In some embodiments, the orthographic projection of the air film hole 21 on the impact plate 3 does not overlap with the impact hole 31. It can be understood that the impact cooling requires the cold air to impact the wall surface to achieve, and the air film hole 21 and the impact hole 31 are staggered to ensure the effective impact area, avoid the cold air from flowing out directly from the air film hole 21, and improve the effect of the impact cooling.

[0033] Furthermore, the side of the top plate 2 facing the impact plate 3 is provided with protrusions 23 or pits 22 arranged at intervals. Therefore, by providing the protrusions 23 or pits 22, the heat exchange area can be effectively increased, and at the same time, the cold air can be disturbed, thereby further increasing the heat exchange capacity and improving the cooling effect.

[0034] Furthermore, the height S of the protrusion 23 satisfies 0.4mm≤S≤0.6mm. It should be noted that the height of the protrusion 23 has a certain influence on the effect of cooling impact. When the height of the protrusion 23 is too large, it will hinder the diffusion of the airflow and reduce the effect of impact cooling. When the protrusion 23 is too small, it will not increase the heat exchange area and the effect of turbulence. Therefore, the reasonable design of the height of the protrusion 23 is of substantial significance for the effect of impact cooling. The inventor of the present application has found through research that when the height S of the protrusion 23 satisfies 0.4mm≤S≤0.6mm, the improvement of the impact cooling effect is most significant.

[0035] Furthermore, the depth D of the pit 22 satisfies 0.3mm≤D≤0.5mm. It should be noted that when the depth of the pit 22 is large, the cold air is easily gathered at the pit 22 and cannot be effectively diffused to the periphery. When the depth of the pit 22 is small, the enhanced effect on the impact cooling is not obvious. Therefore, the reasonable design of the depth of the pit 22 is of substantial significance to the impact cooling effect. The inventor of the present application has found through research that when the depth D of the pit 22 satisfies 0.3mm≤D≤0.5mm, the improvement of the impact cooling effect is most significant.

[0036] Furthermore, the diameter d of the impact hole 31 satisfies 0.4mm≤d≤0.8mm. It should be noted that the diameter of the impact hole 31 has a certain influence on the effect of cooling impact. When the diameter is too large, the airflow velocity is low when passing through the impact hole 31, and high-speed impact cannot be achieved, which leads to a decrease in the cooling effect. When the diameter is too small, the impact hole 31 cannot guarantee the effective flow rate of the airflow. Therefore, a reasonable design of the diameter of the impact hole 31 is of substantial significance to the impact cooling effect. The inventor of the present application has found through research that when the height d of the impact hole 31 satisfies 0.4mm≤d≤0.8mm, the improvement of the impact cooling effect is most significant.

[0037] Furthermore, the spacing H between the impact plate 3 and the top plate 2 satisfies 1.5d≤H≤3.5d. It is understandable that the cooling impact needs to ensure that the airflow is sprayed onto the wall at a certain speed, so the distance between the impact plate 3 and the top plate 2 should be within an appropriate range. When the distance is too large, an effective cooling impact cannot be formed. When the distance is too small, the impact cavity will be too small and cannot provide sufficient buffering for the cold air. Since the diameter of the impact hole 31 is directly related to the maximum distance of the effective impact, the spacing between the impact plate 3 and the top plate 2 should be determined according to the diameter of the impact hole 31. Specifically, the inventor of the present application has found that when the spacing H between the impact plate 3 and the top plate 2 satisfies 1.5d≤H≤3.5d, the impact cooling effect is best.

[0038] The gas turbine according to the embodiment of the present invention comprises the blade tip cooling structure of the turbine blade according to the above-mentioned embodiment.

[0039] The gas turbine of the embodiment of the present invention adopts the blade tip cooling structure of the turbine blade. An impact plate 3 is arranged at a distance below the top plate 2 of the turbine blade 1. The impact plate 3 is provided with impact holes 31 penetrating from top to bottom. The top plate 2 is provided with film holes 21. Therefore, cold air can be sprayed toward the top plate 2 through the impact holes 31 to form impact cooling. In combination with the film holes 21 provided on the top plate 2, the impact cooling and film cooling can be combined, thereby improving the blade tip cooling effect, eliminating the local high temperature area on the blade tip, and improving the temperature uniformity of the blade tip area. The gas turbine has good performance and a long practical life.

[0040] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0041] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0042] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0043] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0044] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0045] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A blade tip cooling structure for a turbine blade, characterized in that: The turbine blade has a cavity, and a cooling air through hole is provided on the bottom wall of the turbine blade. The cooling air through hole is connected to the cavity to allow cooling air to enter. An impact plate is arranged at a distance below the top plate of the turbine blade, and an impact hole is provided on the impact plate which passes through the top and bottom, and an air film hole is provided on the top plate.

2. The tip cooling structure of a turbine blade according to claim 1, characterized in that: A vertically arranged partition is connected between the impact plate and the top plate.

3. The tip cooling structure of a turbine blade according to claim 2, characterized in that: There are multiple baffles, which are arranged at intervals along a first direction, where the first direction is the direction from the leading edge of the turbine blade to the trailing edge of the turbine blade. A partition cavity is formed between adjacent baffles and between the baffle and the turbine blade, and any of the partition cavities has corresponding impact holes and air film holes.

4. The tip cooling structure of a turbine blade according to claim 1, characterized in that: There are a plurality of air film holes, and the arrangement density of the air film holes in a region adjacent to the leading edge of the turbine blade is greater than the arrangement density of the air film holes in a region adjacent to the trailing edge of the turbine blade.

5. The tip cooling structure of a turbine blade according to claim 1, characterized in that: The orthographic projection of the air film hole on the impact plate does not overlap with the impact hole.

6. The tip cooling structure of a turbine blade according to claim 1, characterized in that: The side of the top plate facing the impact plate is provided with protrusions or recesses arranged at intervals.

7. The tip cooling structure of a turbine blade according to claim 6, characterized in that: The height S of the protrusion satisfies 0.4mm≤S≤0.6mm; and / or the depth D of the pit satisfies 0.3mm≤D≤0.5mm.

8. The tip cooling structure of a turbine blade according to claim 1, characterized in that: The diameter d of the impact hole satisfies 0.4 mm≤d≤0.8 mm.

9. The tip cooling structure of a turbine blade according to claim 8, characterized in that: A distance H between the impact plate and the top plate satisfies 1.5d≤H≤3.5d.

10. A gas turbine, characterized in that: A blade tip cooling structure comprising a turbine blade according to any one of claims 1-9.

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