Turbine blade mid-chord cooling channel flow resistance and heat exchange test piece

Abstract

The invention discloses a turbine blade mid-chord cooling channel flow resistance and heat exchange test piece, and relates to the technical field of gas turbines. Comprising a first mid-chord channel assembly and a second mid-chord channel assembly which are spliced in a sealed mode in the thickness direction of the blade, each of the first mid-chord channel assembly and the second mid-chord channel assembly comprises a blade body, a tenon and a bottom plate which are sequentially and oppositely arranged from top to bottom, a cooling channel is formed between the blade bodies, and an air inlet channel is formed between the tenons; and the cooling channel is communicated with the air inlet channel. And a plurality of sealing splicing structures are arranged between the first middle chord channel assembly and the second middle chord channel assembly, so that the stability and the sealing performance of the test piece are ensured. The test piece can simulate the actual working state of the blade mid-chord cooling channel, the flow characteristic and the heat exchange effect of cooling gas in the mid-chord cooling channel can be more accurately researched by using the test piece in a test system, and reliable test data is provided for design and optimization of a gas turbine blade cooling channel structure.

Description

Technical Field

[0001] This invention relates to the field of gas turbine technology, specifically to a test specimen for the flow resistance and heat transfer of the cooling channel in the middle chord of a turbine blade. Background Technology

[0002] Turbine blades are among the most critical high-temperature components in heavy-duty gas turbines. During operation, the inlet gas temperature typically exceeds 1400℃, far surpassing the tolerance temperature of the blade materials. To ensure the safe and reliable operation of the turbine blades, they are designed as hollow structures with complex internal cooling channels. Cooling air flows within these channels, carrying away the heat absorbed by the blades through convection, thus maintaining the temperature within the range of 600℃ to 900℃, thereby ensuring material performance and service life.

[0003] During the product development phase, verifying the flow and heat transfer characteristics of the internal cooling channels of turbine blades is a core aspect of experimental technology. Accurately obtaining the flow resistance characteristics is particularly crucial, as it directly affects the flow rate and pressure distribution of cooling air, thus determining heat transfer efficiency. Only through precise experimental testing to obtain the flow resistance and heat transfer characteristics of the cooling channels can the blade temperature field distribution be accurately calculated. The accuracy of the temperature field distribution is fundamental to predicting blade life and ensuring the safe and reliable operation of turbine components. However, existing technologies have limited experimental research on the flow resistance and heat transfer characteristics of blade cooling channels.

[0004] Existing patent CN116519311A discloses the design and testing method of a gas turbine blade test piece with multiple replaceable channels, which is assembled from substructures such as the blade body, baffles, spoilers, and cover plates. However, this patent only focuses on the replaceability of the blade structure and does not involve testing methods for the flow resistance and heat transfer characteristics of the cooling channels, thus failing to meet the needs of flow resistance characteristic analysis.

[0005] Existing patent CN118670819A discloses a heat transfer test piece and heat transfer test method for simulating the impact diaphragm of the blade cavity. It uses copper plates, heating plates and other materials to simulate impact cooling. However, its test piece only targets the local heat transfer of the impact diaphragm, does not consider the flow resistance characteristics of the complete cooling channel, and cannot reflect the comprehensive influence of the complex flow field inside the real blade.

[0006] In summary, none of the existing patents provide a test specimen suitable for the flow resistance and heat transfer characteristics of turbine blade cooling channels. Therefore, there is an urgent need to develop a test specimen that can accurately test the flow resistance and heat transfer characteristics of turbine blade cooling channels. Summary of the Invention

[0007] Based on the current state of technology, this invention proposes a test specimen for the flow resistance and heat transfer of the cooling channel in the mid-chord of a turbine blade. By simulating the structure of the cooling channel in the mid-chord of a turbine blade, the flow and heat transfer characteristics of cooling air in an actual blade can be better studied. The test specimen has a robust structure, is easy to assemble, and has good sealing performance.

[0008] To achieve the above objectives, this invention proposes a test specimen for the flow resistance and heat transfer of the mid-chord cooling channel in a turbine blade, the specific technical solution of which is as follows:

[0009] A heat exchange test specimen for a turbine blade's mid-chord cooling channel includes a first mid-chord channel assembly and a second mid-chord channel assembly sealed and spliced ​​along the blade's thickness direction. The splicing surface of the first mid-chord channel assembly is convex, and the splicing surface of the second mid-chord channel assembly is concave. The first and second mid-chord channel assemblies include a blade body, a tenon, and a base plate arranged opposite each other from top to bottom. The splicing surface of the blade body is provided with a cooling channel, and the splicing surface of the tenon is provided with an air intake channel.

[0010] Furthermore, multiple sealed splicing structures are provided between the first middle chord channel assembly and the second middle chord channel assembly.

[0011] Furthermore, the sealing splicing structure includes flanges disposed on the edge of the blade and the edge of the tenon, and a plurality of through threaded holes disposed on the flanges.

[0012] Furthermore, the connection between the blade and the tenon is provided with a plurality of threaded holes in the horizontal direction, which penetrate the first middle chord channel assembly and the second middle chord channel assembly.

[0013] Furthermore, flanges are provided at the top and sides of the blade. The flange at the top of the blade near the cooling channel has a horizontally penetrating boss and groove mating structure, and the flanges on both sides of the blade near the cooling channel have a vertically penetrating boss and groove mating structure.

[0014] Furthermore, flanges are provided on both sides of the tenon, and the flanges on both sides of the tenon near the air intake channel are provided with a vertically penetrating boss and groove matching structure.

[0015] Furthermore, the cooling channel includes three parallel vertical cooling channels connected by a U-shaped bend, and the sealing splicing structure also includes a boss and groove matching structure on the partition plate between adjacent cooling channels.

[0016] Furthermore, the air intake channel includes two channels, and the sealing splicing structure also includes a boss and groove matching structure disposed on the partition plate between the two air intake channels.

[0017] Furthermore, the boss or groove on the blade splicing surface is connected to the boss or groove on the tenon splicing surface.

[0018] Furthermore, the circumferential edge of the base plate is provided with a plurality of threaded holes penetrating the base plate.

[0019] Furthermore, the heat exchange test specimen is made of transparent organic glass, and the inner surface of the cooling channel of the test specimen is uniformly coated with a hot-color liquid crystal coating.

[0020] The present invention also provides a flow resistance test piece for a turbine blade mid-chord cooling channel, used for flow resistance testing. The flow resistance test piece has the same structure as the above-mentioned turbine blade mid-chord cooling channel heat exchange test piece. The blade body of the second mid-chord channel assembly of the flow resistance test piece is provided with a plurality of equally spaced static pressure test holes in the vertical direction corresponding to the position of the cooling channel. The static pressure test holes penetrate the blade body and are used to install static pressure probes.

[0021] The present invention also provides a test specimen for flow resistance and heat transfer of the mid-chord cooling channel of a turbine blade. The test specimen has the same structure as the above-mentioned test specimen for heat transfer of the mid-chord cooling channel of a turbine blade. The blade body of the second mid-chord channel assembly of the flow resistance test specimen is provided with a plurality of equally spaced static pressure measuring holes in the vertical direction corresponding to the position of the cooling channel. The static pressure measuring holes penetrate the blade body and are used to install static pressure probes.

[0022] Based on the above technical solution, the present invention has at least the following beneficial effects:

[0023] 1. The present invention proposes a test specimen for the flow resistance and heat transfer of the cooling channel in the middle chord of a turbine blade. By decoupling the complex cooling channel inside the blade into an independent test unit, the test accuracy of the flow resistance and heat transfer performance is significantly improved. At the same time, the test specimen is made of transparent material and the inner surface of the cooling channel is coated with thermochromic liquid crystal. The heat transfer coefficient of the cooling channel inside the blade can be accurately tested using transient thermochromic liquid crystal testing technology, and the flow resistance characteristic parameters can be obtained simultaneously.

[0024] 2. This invention proposes a test specimen for the flow resistance and heat transfer of the cooling channel in the middle chord of a turbine blade, which consists of two relatively sealed spliced ​​components. This design enhances the overall structural stability. At the same time, the multiple sealed spliced ​​structures can not only effectively fill the sealing between the edges of the components to prevent cooling gas leakage, but also improve the sealing between the cooling channels to ensure that the cooling gas flows completely according to the designed cooling channels.

[0025] 3. This invention proposes a test piece for the flow resistance and heat transfer of the cooling channel in the middle chord of a turbine blade. The design of the blade body, tenon and base plate being integrally formed eliminates the need for welding, riveting and other connection points between the parts, reducing the assembly steps between components and thus avoiding the impact of assembly errors on the dimensional and shape accuracy of the cooling channel.

[0026] 4. This invention proposes a test specimen for the flow resistance and heat transfer of the mid-chord cooling channel of a turbine blade, which can realistically simulate the actual working state of the mid-chord cooling channel of a turbine blade. It can more accurately study the flow characteristics and heat transfer effect of cooling gas in the mid-chord cooling channel, and provide reliable test data for the design and optimization of the cooling structure of gas turbine blades. Attached Figure Description

[0027] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0028] Figure 1 This is a schematic diagram of the structure of a heat exchange test piece for a turbine blade mid-chord cooling channel proposed in this invention;

[0029] Figure 2 This is a schematic diagram of the first mid-chord channel assembly structure of a heat exchange test piece for a turbine blade mid-chord cooling channel proposed in this invention;

[0030] Figure 3 This is a schematic diagram of the second middle chord channel assembly structure of a heat exchange test piece for a turbine blade middle chord cooling channel proposed in this invention;

[0031] Figure 4 This is a partial structural schematic diagram of the first mid-chord channel assembly of a heat exchange test specimen for a turbine blade mid-chord cooling channel proposed in this invention;

[0032] Figure 5 This is a schematic diagram of the structure of a heat exchange test piece for a turbine blade mid-chord cooling channel proposed in this invention;

[0033] Figure 6 This is a schematic diagram of the flow resistance test piece for the mid-chord cooling channel of a turbine blade proposed in this invention;

[0034] Figure 7 This is a schematic diagram of the turbine blade cooling channel in an embodiment of the present invention.

[0035] Reference numerals: 10-First middle chord channel assembly, 20-Second middle chord channel assembly, 11-First blade, 12-First tenon, 13-First base plate, 21-Second blade, 22-Second tenon, 23-Second base plate, 31-Static pressure measuring hole. Detailed Implementation

[0036] The present invention will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed by the present invention.

[0037] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0038] To ensure the safe and reliable operation of turbine blades, a complex cooling channel structure is designed inside the blades. The cooling channels inside the turbine blades employ three different channel structures. (See reference...) Figure 7 As shown in the diagram, the black areas represent the cooling channels, including the leading-edge cooling channel, the mid-edge cooling channel, and the trailing-edge cooling channel. The mid-edge cooling channel comprises the cooling channel for the blade body (above the dotted line) and the intake channel for the tenon section (below the dotted line). The mid-edge cooling channel is serpentine, consisting of three vertical channels. The bottom of one cooling channel connects to the intake channel, and its top connects to the top of the middle cooling channel. The bottom of the middle cooling channel and the bottom of the other cooling channel are connected by a U-shaped bend. The top of the other cooling channel is an open end. The intake channel consists of two channels. Cooling air enters through the intake channel, flows sequentially through the three cooling channels, and exits from the open end at the top.

[0039] The present invention proposes a test specimen for the flow resistance and heat transfer of the mid-chord cooling channel of a turbine blade, which can be used in the test system to simulate the actual operating conditions of the mid-chord cooling channel of a turbine blade in order to test the flow resistance and heat transfer characteristics of the mid-chord cooling channel of the turbine blade.

[0040] Example 1

[0041] See Figure 1-5 As shown, this embodiment provides a heat transfer test specimen for the mid-chord cooling channel of a turbine blade. (See reference...) Figure 1 As shown, the blade portion and tenon portion of the heat transfer test specimen can be configured as an integral structure. The heat transfer test specimen includes a first mid-chord channel assembly 10 and a second mid-chord channel assembly 20, wherein the first mid-chord channel assembly is... Figure 1 The first half of the component, the second middle chord channel component is Figure 1 The rear half of the assembly, the first middle chord channel assembly 10 and the second middle chord channel assembly 20 are spliced ​​and installed relative to each other along the blade thickness direction, and the splicing surface of the first middle chord channel assembly 10 and the second middle chord channel assembly 20 is a curved surface.

[0042] See Figure 2 and Figure 3The figures show schematic diagrams of the splicing surfaces of the first mid-chord channel assembly 10 and the second mid-chord channel assembly 20, respectively. The first mid-chord channel assembly 10 includes a first blade 11 at the upper end, a first tenon 12 in the middle, and a first base plate 13 at the bottom. The first blade 11, the first tenon 12, and the first base plate 13 are integrally formed, and the bottom surface of the first base plate 13 is flush with the bottom surface of the first tenon 12. The second mid-chord channel assembly 20 includes a second blade 21 at the upper end, a second tenon 22 in the middle, and a second base plate 23 at the bottom. The second blade 21, the second tenon 22, and the second base plate 23 are integrally formed, and the bottom surface of the second base plate 23 is flush with the bottom surface of the second tenon 22. A mid-chord cooling channel structure is provided at the splicing surface of the first blade 11 and the second blade 21, and a tenon air intake channel is provided at the splicing surface of the first tenon 12 and the second tenon 22. The air intake channel and the cooling channel are connected. After the first mid-chord channel assembly 10 and the second mid-chord channel assembly 20 are spliced ​​together, a complete turbine blade mid-chord cooling channel and air intake channel are formed.

[0043] Specifically, since the turbine blades have a radial inclination that shifts from the pressure surface to the suction surface, in order to ensure that the cooling channel of the test piece is consistent with the actual design, the splicing surfaces of the first blade 11 and the first tenon 12 are convex, while the splicing surfaces of the second blade 21 and the second tenon 2 are concave.

[0044] For details, please refer to Figure 2 As shown, a horizontal flange is provided at the top of the first blade 11, and vertical flanges are provided on both sides of the first blade 11 and the first tenon 12. Each flange has a threaded hole that penetrates the flange. A through threaded hole is also provided at the connection between the first blade 11 and the first tenon 12. The flanges on both sides of the first blade 11 have a vertically penetrating boss on the side near the cooling channel, and the flange at the top of the first blade 11 has a horizontally penetrating boss on the side near the cooling channel. One end of this boss extends to the opening at the top of the central cooling channel, and the other end connects to the vertically penetrating boss. Vertically penetrating bosses are provided on the partitions between adjacent channels in the serpentine cooling channel of the first blade 11. All bosses serve to seal the cooling channel during assembly.

[0045] See Figure 4 As shown, the partition between the two air intake channels of the first tenon 12 and both sides of the air intake channel are provided with protrusions that run vertically through the partition. The protrusions on the first tenon 12 are integrally connected with the protrusions on the first blade 11, which are used to seal the air intake channel during splicing and installation.

[0046] See Figure 3As shown, the difference between the second middle chord channel assembly 20 and the first middle chord channel assembly 10 is that the second middle chord channel assembly 20 has grooves at positions corresponding to all the bosses of the first middle chord channel assembly 10. The bosses and grooves can engage with each other. After the first middle chord channel assembly 10 and the second middle chord channel assembly 20 are spliced ​​and installed, they can be further pre-tightened through the threaded holes to achieve stable installation and sealing of the turbine blade middle chord cooling channel.

[0047] Optionally, rubber or sealant may be provided in the groove to further improve the sealing of the cooling channel in the turbine blade.

[0048] See Figure 5 As shown, the first base plate 13 and the second base plate 23 are spliced ​​together to form a rectangle. Multiple threaded holes are opened on the edge of the rectangular base plate to seal the test piece with the air supply chamber interface in the test system.

[0049] The aforementioned turbine blade cooling channel heat transfer test specimen was made of transparent plexiglass, with a thermochromic liquid crystal coating uniformly sprayed onto the inner surface of the cooling channel. During the experiment, multiple high-precision temperature sensors were placed at key locations inside the cooling channel. When compressed air entered the cooling channel, the temperature sensors monitored the temperature change of the thermochromic liquid crystal coating in real time. Simultaneously, an external high-resolution CCD camera continuously captured and recorded transient temperature field distribution images of the cooling channel inside the test specimen at different times. Based on the transient temperature field image data, a complete curve of the surface temperature change of the cooling channel over time can be accurately obtained. Furthermore, by combining the measured transient temperature change data with the gas temperature parameters and flow characteristic parameters, and using relevant heat transfer theories and calculation formulas, the detailed distribution of the heat transfer coefficient within the cooling channel of the test specimen can be derived.

[0050] Example 2

[0051] See Figure 6 As shown, this embodiment provides a flow resistance test piece for the cooling channel of a turbine blade. The flow resistance test piece has a structure that is basically the same as the heat exchange test piece in Embodiment 1. The difference is that the flow resistance test piece does not need to use a transparent organic glass material and the inner surface of the cooling channel does not need to be coated with a thermochromic liquid crystal coating. Metal materials can be used. Multiple static pressure test holes 31 are set at equal intervals in the vertical direction on the blade body of the second middle chord channel assembly (rear half assembly) of the flow resistance test piece, corresponding to the position of the cooling channel. The static pressure test holes 31 penetrate the second middle chord channel assembly, and the static pressure probe of the test system is inserted and installed through the static pressure test holes 31.

[0052] Example 3

[0053] This embodiment provides a test specimen for the flow resistance and heat transfer of the cooling channel in the middle chord of a turbine blade. Its structure is the same as the flow resistance test specimen in Embodiment 2, but it is made of transparent acrylic glass and has a thermochromic liquid crystal coating uniformly sprayed onto the inner surface of the cooling channel. This test specimen can be used simultaneously for flow resistance and heat transfer tests without requiring replacement of the test specimen, significantly improving testing efficiency and ensuring data consistency.

[0054] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0055] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0056] It should be noted that, in the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

Claims

1. A heat transfer test specimen for a mid-chord cooling channel in a turbine blade, characterized in that: The device includes a first center chord channel assembly and a second center chord channel assembly that are sealed and spliced ​​along the thickness direction of the blade. The splicing surface of the first center chord channel assembly is convex, and the splicing surface of the second center chord channel assembly is concave. The first center chord channel assembly and the second center chord channel assembly include a blade body, a tenon, and a base plate arranged opposite each other from top to bottom. The splicing surface of the blade body is provided with a cooling channel, and the splicing surface of the tenon is provided with an air intake channel.

2. The heat transfer test specimen for the chordal cooling channel of a turbine blade according to claim 1, characterized in that: Multiple sealed splicing structures are provided between the first middle chord channel assembly and the second middle chord channel assembly.

3. The heat transfer test specimen for the chordal cooling channel of a turbine blade according to claim 2, characterized in that: The sealing splicing structure includes flanges disposed on the edge of the blade and the edge of the tenon, and multiple through threaded holes disposed on the flanges.

4. The heat transfer test specimen for the chordal cooling channel of a turbine blade according to claim 3, characterized in that: The connection between the blade and the tenon is provided with multiple threaded holes in the horizontal direction, penetrating the first middle chord channel assembly and the second middle chord channel assembly.

5. The heat transfer test specimen for the chordal cooling channel of a turbine blade according to claim 4, characterized in that: Flanges are provided at the top and both sides of the blade. The flange at the top of the blade has a horizontally penetrating boss and groove matching structure on the side near the cooling channel. The flanges on both sides of the blade have a vertically penetrating boss and groove matching structure on the side near the cooling channel.

6. The heat transfer test specimen for the chordal cooling channel of a turbine blade according to claim 5, characterized in that: Flanges are provided on both sides of the tenon, and the flanges on both sides of the tenon near the air intake channel have a vertically penetrating boss and groove matching structure.

7. The heat transfer test specimen for the chordal cooling channel of a turbine blade according to claim 6, characterized in that: The cooling channel includes three parallel vertical cooling channels connected by a U-shaped bend. The sealing splicing structure also includes a boss and groove matching structure on the partition between adjacent cooling channels.

8. The heat transfer test specimen for the chordal cooling channel of a turbine blade according to claim 7, characterized in that: The air intake channel includes two channels, and the sealing splicing structure also includes a boss and groove matching structure disposed on the partition plate between the two air intake channels.

9. The heat transfer test specimen for the chordal cooling channel of a turbine blade according to claim 8, characterized in that: The boss or groove on the blade splicing surface is connected to the boss or groove on the tenon splicing surface.

10. The heat transfer test specimen for the chordal cooling channel of a turbine blade according to any one of claims 1-9, characterized in that: The base plate has multiple threaded holes through it along its circumferential edge.

11. The heat transfer test specimen for the chordal cooling channel of a turbine blade according to claim 10, characterized in that: The heat exchange test specimen is made of transparent organic glass, and the inner surface of the cooling channel of the test specimen is uniformly sprayed with a hot-color liquid crystal coating.

12. A flow resistance test specimen for a turbine blade mid-chord cooling channel, used for flow resistance testing, wherein the flow resistance test specimen has the same structure as the heat transfer test specimen for a turbine blade mid-chord cooling channel according to any one of claims 1-10, characterized in that: The blade of the second chord channel assembly of the flow resistance test piece has multiple equally spaced static pressure test holes arranged vertically in the direction corresponding to the cooling channel. The static pressure test holes penetrate the blade and are used to install static pressure probes.

13. A test specimen for flow resistance and heat transfer in the mid-chord cooling channel of a turbine blade, wherein the test specimen has the same structure as the test specimen for heat transfer in the mid-chord cooling channel of a turbine blade according to any one of claims 1-11, characterized in that: The blade of the second chord channel assembly of the flow resistance test piece has multiple equally spaced static pressure test holes arranged vertically in the direction corresponding to the cooling channel. The static pressure test holes penetrate the blade and are used to install static pressure probes.

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