Oscillation impact cooling structure for turbine blade of gas turbine

Abstract

The invention discloses a gas turbine blade oscillation impact cooling structure which comprises a plurality of cold air cavities and a plurality of impact cavities which are arranged in a gas turbine blade, one cold air cavity corresponds to the multiple impact cavities, and the inner wall face of each impact cavity is a heat exchange target face. And each impact cavity is communicated with the corresponding cold air cavity through a plurality of oscillation impact holes, and the structure can improve the cooling effect of the turbine blade of the gas turbine.

Description

Technical Field

[0001] This invention belongs to the field of turbomachinery technology and relates to a gas turbine blade oscillation impact cooling structure. Background Technology

[0002] Gas turbines, often referred to as the "crown jewel of the equipment manufacturing industry," are widely used in aviation, shipbuilding, and power generation. To improve gas turbine efficiency and reduce fuel consumption, turbine inlet temperatures have increased from 1400K in the 1970s to over 2000K currently, far exceeding the tolerance of turbine materials. With the continuous increase in turbine inlet temperature, the heat load and thermal stress on the blades gradually increase. To improve gas turbine thermal efficiency and extend blade lifespan, it is essential to research new and advanced cooling methods.

[0003] Currently, the commonly used cooling methods for turbine blades can be divided into two types: internal cooling and external cooling. Internal cooling involves cooling the blade material as cool air flows through the internal cooling channels. One important internal cooling method is impingement cooling. Impingement cooling currently involves forming impingement holes inside the blade, from which cool air flows out, forming a high-speed jet that impacts the heat exchange target surface, thus cooling the blade. Air is currently the primary cooling medium, but water vapor or a mixture of air and water mist can also be used. Because the impingement holes in turbine blades are often arranged in single or multiple rows, the upstream impingement jet generates crossflow within the impingement cavity, forcing the downstream impingement jet to deflect. This crossflow weakens the impact cooling effect. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a gas turbine blade oscillation impact cooling structure that can improve the cooling effect of gas turbine blades.

[0005] To achieve the above objectives, the present invention discloses an oscillation impact cooling structure for gas turbine blades, comprising a plurality of cold air chambers and a plurality of impact chambers disposed within the gas turbine blades, wherein one cold air chamber corresponds to a plurality of impact chambers, the inner wall surface of each impact chamber is a heat exchange target surface, and each impact chamber is connected to the corresponding cold air chamber through a plurality of oscillation impact holes.

[0006] Furthermore, a support structure is provided inside the oscillation impact hole, and a turbulence-disrupting structure is provided on the support structure.

[0007] Furthermore, the turbulence structure is a ring structure.

[0008] Furthermore, the cross-section of the disturbance structure is a triangular structure or a cross-sectional shape capable of inducing forced oscillations.

[0009] Furthermore, the shape and size of the cooling chamber are adjusted according to the blade profile of the gas turbine.

[0010] Furthermore, the cooling working fluid enters the cold gas chamber, and then enters the impact chamber after forming a high-speed oscillating impact jet through the oscillating impact hole.

[0011] Furthermore, the cooling medium is air, steam, or mist.

[0012] Furthermore, when the cooling medium enters the oscillating impact hole and flows through the turbulent structure, the flow velocity increases and the pressure decreases on both sides of the turbulent structure. Directly downstream of the turbulent structure, the reduced flow velocity generates an adverse pressure gradient. Since the kinetic energy of the cooling medium is insufficient to overcome the adverse pressure gradient, the boundary layer closely attached to the surface of the turbulent structure separates to form a shear layer. The separation of the shear layer forms vortices. After the Reynolds number reaches a certain value, the stability of the vortex is destroyed, and the vortices on both sides of the turbulent structure alternately fall off, thus forming a forced oscillating impact jet with vortices.

[0013] Furthermore, each cooling chamber is sequentially located within the turbine blades of the gas turbine.

[0014] Furthermore, each impact chamber is sequentially located within the turbine blades of the gas turbine.

[0015] The present invention has the following beneficial effects: In specific operation, the oscillating impact cooling structure for gas turbine blades described in this invention forms an oscillating impact jet through the oscillating impact hole and impacts the heat exchange target surface at high speed, thereby reducing the thickness of the boundary layer of the heat exchange target surface, intensifying the convective heat transfer between the cold gas and the target surface, reducing the influence of crossflow phenomenon, and improving the cooling effect of the gas turbine blades. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1a This is a schematic diagram of the structure of the present invention; Figure 1b This is a cross-sectional view of the present invention; Figure 2a This is a front view of the oscillation impact hole 2 in this invention; Figure 2b This is a rear view of the oscillation impact hole 2 in this invention; Figure 3a Distribution contour plot of Nusselt number (Nu) at the leading edge of an oscillating impact-cooled turbine blade; Figure 3b A cloud map showing the distribution of Nusselt number (Nu) at the leading edge of a conventionally impact-cooled turbine blade; Figure 4a Streamline diagram of the impact jet cooled by oscillating impact; Figure 4b This is a streamline diagram of the impact jet in traditional impact cooling.

[0018] Among them, 1 is the cold air chamber, 2 is the oscillation impact hole, 3 is the impact chamber, 4 is the turbulence structure, and 5 is the support structure. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] In the description of this invention, it should be understood that the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0021] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0022] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes such combinations. For example, A and / or B can represent three cases: A alone, A and B simultaneously, and B alone. Additionally, the character " / " in this invention generally indicates that the preceding and following objects have an "or" relationship.

[0023] It should be understood that although terms such as first, second, third, etc., may be used in the embodiments of the present invention to describe the preset range, these preset ranges should not be limited to these terms. These terms are only used to distinguish the preset ranges from one another. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0024] Depending on the context, the word "if" as used here can be interpreted as "when," "when," "in response to determination," or "in response to detection." Similarly, depending on the context, the phrase "if determination" or "if detection (of the stated condition or event)" can be interpreted as "when determination," "in response to determination," "when detection (of the stated condition or event)," or "in response to detection (of the stated condition or event)."

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0026] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0027] refer to Figure 1a , Figure 1b , Figure 2a and Figure 2b The gas turbine blade oscillation impact cooling structure of the present invention includes a plurality of cold air chambers 1 and a plurality of impact chambers 3 disposed in the gas turbine blade, wherein one cold air chamber 1 corresponds to a plurality of impact chambers 3, the inner wall surface of each impact chamber 3 is a heat exchange target surface, and each impact chamber 3 is connected to the corresponding cold air chamber 1 through a plurality of oscillation impact holes 2.

[0028] It should be noted that the present invention provides a gas supply space for the oscillating impact cooling medium through the cold air chamber 1. The cooling working medium first enters the cold air chamber 1, and then forms an oscillating impact jet after passing through the oscillating impact hole 2. The heat exchange target surface is then cooled by the impact jet.

[0029] In this embodiment, a support structure 5 is provided inside the oscillation impact hole 2, and a turbulence structure 4 is provided on the support structure 5. The turbulence structure 4 is an annular structure, and the cross-section of the turbulence structure 4 is a triangular structure or a cross-sectional shape that can induce forced oscillation.

[0030] The cooling chamber 1 is arranged inside the turbine blade of the gas turbine. Its shape and size can be adjusted according to the blade profile. The cooling working fluid enters the cooling chamber 1, and then enters the impact chamber 3 after forming a high-speed oscillating impact jet through the oscillating impact hole 2. The inner wall of the impact chamber 3 is the heat exchange target surface, which is also the inner wall of the leading edge of the turbine blade. Therefore, the oscillating impact jet has a cooling effect on the leading edge of the turbine blade.

[0031] It should be noted that the present invention has the following characteristics: This invention is compatible with existing gas turbine blade structures and significantly increases the cooling intensity at the blade leading edge, allowing for further increases in the initial gas temperature. This invention does not limit the type of cooling medium; air, steam, and aerosol cooling are all acceptable. This invention requires no external auxiliary equipment and can directly replace the existing impact cooling structure of gas turbine blades.

[0032] When the cooling medium enters the oscillating impact hole 2 and flows through the turbulence structure 4, the velocity increases and the pressure decreases on both sides of the turbulence structure 4. Downstream of the turbulence structure 4, the decreased velocity generates an adverse pressure gradient. Since the kinetic energy of the cooling medium is insufficient to overcome this gradient, the boundary layer adhering to the surface of the turbulence structure 4 separates, forming a shear layer. This shear layer separation creates vortices. Once the Reynolds number reaches a certain value, the vortex stability is disrupted, and the vortices on both sides of the turbulence structure 4 alternately detach, thus forming a forced oscillating impact jet with vortices. Compared to a steady-state impact jet, the oscillating impact jet provides continuous lateral momentum after impacting the heat exchange target surface, delaying the decay of the heat exchange core region and expanding the high heat transfer coefficient area on the heat exchange target surface. Furthermore, the oscillating impact jet also increases the periodic high-frequency shear force that disrupts the thermal boundary layer. The vortices it carries further generate secondary flow on the heat exchange target surface, increasing the contact area and convection intensity between the cooling medium and the heat exchange target surface. In addition, the radial and circumferential mixing between the vortices is very strong, which enhances the heat exchange between the cold gas micro-clusters, reduces the overall temperature of the cooling medium, and thus maintains a larger temperature difference between the heat exchange target surface and the cooling medium.

[0033] The combined effect of the above factors results in a significant improvement in the cooling effect of oscillating shock compared to traditional steady-state shock cooling. Computational fluid dynamics numerical calculations show that ( Figure 3a and Figure 3bUnder the boundary conditions of a main inlet total temperature of 709 K, a main inlet pressure of 344.74 kPa, an outlet pressure of 211.497 kPa, a total cooling medium temperature of 309 K, and a cooling medium flow rate of 0.0044 kg / s, the average Nusselt number at the leading edge of the turbine blades using this invention is 97.2, while that of the traditional impingement cooling blades is 88.2, representing a 10.2% increase in the Nusselt number. The average leading edge temperature of the turbine blades using this invention is 544 K, while that of the traditional impingement cooling blades is 557 K, representing a 13 K decrease in the blade leading edge temperature. The overall heat transfer coefficient is defined as a dimensionless number representing the ratio of the Nusselt number to the flow resistance, used to evaluate the energy efficiency of the cooling structure. The ratio of the overall heat transfer coefficient of this invention to that of the traditional impingement cooling structure is 1.08, representing an 8% improvement.

[0034] This invention demonstrates superior resistance to crossflow effects compared to traditional impact cooling structures. Computational fluid dynamics numerical calculations show that ( Figure 4a and Figure 4b The oscillating impact jet of this invention is closer to being parallel to the axis of the impact hole, while the traditional impact cooling jet exhibits significant crossflow. Furthermore, the velocity dispersion of each impact jet in this invention is lower, resulting in a more uniform cooling effect on the heat exchange target surface.

[0035] Furthermore, the turbulence structure 4 in the oscillating impact hole 2 increases the velocity component of the cooling medium perpendicular to the heat exchange target surface, making the oscillating impact jet closer to being parallel to the axis of the impact hole, thus reducing the influence of crossflow. The heat exchange target surface directly opposite the oscillating impact hole 2 is a high heat transfer intensity region, resulting in more uniform heat transfer across the turbine blade. The generation of the oscillating impact jet in this invention does not require external auxiliary equipment, has a simple and compact structure, and is not limited to any type of cooling medium. This invention can be applied to the leading edge cooling of turbine blades, allowing for further increases in the initial inlet temperature of gas turbines.

[0036] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and disclosure of the invention. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the following claims.

[0037] It should be understood that the present invention is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

[0038] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any simple modifications, alterations, or equivalent structural changes made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A gas turbine turbine blade oscillating impingement cooling structure, characterized by, The application relates to a cooling device for a gas turbine, comprising a plurality of cold gas cavities (1) and a plurality of impact cavities (3) arranged in a gas turbine turbine blade, wherein one cold gas cavity (1) corresponds to a plurality of impact cavities (3), the inner wall surface of each impact cavity (3) is a heat exchange target surface, and each impact cavity (3) is connected with the corresponding cold gas cavity (1) through a plurality of oscillating impact holes (2).

2. The gas turbine turbine blade oscillating impingement cooling structure according to claim 1, characterized in that A support structure (5) is arranged in the oscillating impact hole (2), and a spoiler structure (4) is arranged on the support structure (5).

3. The gas turbine turbine blade oscillating impingement cooling structure according to claim 2, characterized in that The spoiler structure (4) is an annular structure.

4. The gas turbine turbine blade oscillating impingement cooling structure according to claim 3, characterized in that The cross section of the spoiler structure (4) is a triangular structure or a cross section shape capable of exciting forced oscillation.

5. The gas turbine turbine blade oscillating impingement cooling structure according to claim 1, wherein, The shape and size of the cold gas cavity (1) are adjusted according to the blade type of the gas turbine turbine blade.

6. The gas turbine turbine blade oscillating impingement cooling structure according to claim 2, wherein, The cooling medium enters the cold gas cavity (1), and then enters the impact cavity (3) after forming a high-speed oscillating impact jet through the oscillating impact hole (2).

7. The gas turbine turbine blade oscillating impingement cooling structure according to claim 6, characterized in that The cooling medium is air, steam or gas mist.

8. The gas turbine turbine blade oscillating impingement cooling structure according to claim 7, characterized in that When the cooling medium flows through the spoiler structure (4) in the oscillating impact hole (2), the flow velocity increases and the pressure decreases on both sides of the spoiler structure (4); in the immediate downstream of the spoiler structure (4), the flow velocity decreases to generate an adverse pressure gradient, and since the kinetic energy of the cooling medium is insufficient to overcome the adverse pressure gradient, the boundary layer close to the surface of the spoiler structure (4) separates to form a shear layer, the vortex is formed by the separated shear layer, the vortex stability is destroyed when the Reynolds number reaches a certain value, and the vortex on both sides of the spoiler structure (4) is alternately shed, so that the forced oscillating impact jet with vortex is formed.

9. The gas turbine turbine blade oscillating impingement cooling structure according to claim 1, wherein, Each cold gas cavity (1) is arranged in the gas turbine turbine blade in sequence.

10. The gas turbine turbine blade oscillating impingement cooling structure of claim 1, wherein, Each impact cavity (3) is arranged in the gas turbine turbine blade in sequence.

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