A total pressure measurement test method suitable for small size blade inner flow passage

Abstract

The application discloses a total pressure measurement test method suitable for small-size blade inner flow channel, which comprises the following steps: step S1: preparing a total pressure probe and selecting an experimental object, and dividing the selected turbine blade into two parts; step S2: processing a turbine blade leading edge part; step S3: connecting the total pressure probe with the turbine blade leading edge part, so that the total pressure probe is communicated with the inner flow channel through a measuring hole; step S4: processing the rest part of the turbine blade, opening a cavity at a section position, and arranging the other end of the total pressure probe into the cavity; step S5: bonding the turbine blade leading edge part and the rest part of the turbine blade, and restoring to a complete blade state; and step S6: connecting a measuring device to the part of the turbine blade leading out the total pressure probe, and performing the total pressure measurement test of the inner flow channel. The application has small size, small influence on the original flow field of the turbine blade inner flow channel, discrete arrangement of the measuring device, simultaneous measurement of multiple points, reliable measurement result and good accuracy.

Description

Technical Field

[0001] This invention belongs to the field of pressure testing technology, and in particular relates to a total pressure measurement test method suitable for the internal flow channel of small-sized blades. Background Technology

[0002] High-temperature turbines are a crucial component of gas turbine engines. Increasing the turbine inlet temperature is an effective way to increase engine thrust and power. However, raising the turbine inlet temperature deteriorates the working environment of high-temperature turbine components, leading to poor reliability and short service life. Therefore, turbine blades require more efficient cooling technologies. Film cooling, a widely used and efficient cooling technology for high-temperature components, involves creating discrete holes on the turbine blade surface to jet the cooling medium from inside the blade. Under the action of the high-temperature mainstream, the cooling medium is pressed onto the blade surface, forming a film that not only separates the blade wall from the high-temperature mainstream combustion gas but also removes heat from the blade wall.

[0003] The flow coefficient, as a crucial parameter in the design phase of film cooling structures, is primarily used to regulate the actual distribution of cooled air and assess the pressure loss of fluid flowing through the film orifices. Measuring and calculating the flow coefficient of film orifices typically requires obtaining the total pressure of the cooled air at the orifice inlet. During experiments, instruments are often used to extract the total pressure value at the internal flow channel where the film orifices are located. However, real aero-engine turbine blades are relatively small, and their surfaces often have densely distributed rows of film orifices, especially at the leading edge. Taking the turbine blade shown in the manual as an example, the internal flow channel has rows of film orifices distributed on both the suction and pressure surfaces of the blade.

[0004] Given the small size of real turbine blades, traditional total pressure measurement methods typically employ "scaled-up model" experiments. However, for models with intricate structures and complex flow fields, scaled-up models fail to accurately represent the actual operating environment of turbine blades. Furthermore, the dense array of film gas holes at the leading edge of real turbine blades makes it difficult to install and deploy measurement equipment using traditional total pressure measurement methods, which also significantly interfere with the original flow field within the turbine blade's internal channels.

[0005] Therefore, there is an urgent need for a test method for measuring total pressure in the internal flow channels of small-sized blades to solve the above-mentioned technical problems. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention proposes a total pressure measurement test method suitable for the internal flow channels of small-sized blades.

[0007] To achieve the above objectives, the present invention provides a total pressure measurement test method suitable for the internal flow channel of small-sized blades, comprising the following steps:

[0008] Step S1: Prepare the total pressure probe and select the experimental object. Divide the selected turbine blade into two parts, namely the leading edge part of the turbine blade and the rest of the turbine blade.

[0009] Step S2: For the leading edge of the turbine blade, along the flow channel direction inside the turbine blade, make a measurement hole on the wall that matches the total pressure probe according to the blade height.

[0010] Step S3: Connect the total pressure probe to the leading edge of the turbine blade, so that the total pressure probe passes through the measuring hole and connects with the inner flow channel;

[0011] Step S4: Process the remaining part of the turbine blade, open a cavity at the cross-section, extend the other end of the total pressure probe into the cavity and arrange it along the cavity, and lead the total pressure probe out of the turbine blade.

[0012] Step S5: Bond the leading edge of the turbine blade to the rest of the turbine blade to restore it to a complete blade state;

[0013] Step S6: Connect the measuring equipment to the part of the total pressure probe that extends out of the turbine blade to conduct a total pressure measurement test in the internal flow channel.

[0014] Preferably, in step S1, the total pressure probe includes an L-shaped probe, one end of which extends into the inner flow channel through the measuring hole, and the other end of which extends out of the measuring hole and is inserted and fixed on the connecting block. The connecting block is adapted to the measuring hole and embedded and fixed in the measuring hole. The end of the connecting block away from the probe is connected to a pressure-sensing hose.

[0015] Preferably, the first end face of the connecting block extends into the measuring hole and has a connecting hole adapted to the probe; the second end face of the connecting block away from the probe is fixed with a cylindrical boss, and the pressure-sensing hose is inserted and fixed in the boss; the first end face is flush with the interface between the measuring hole and the inner flow channel, and the second end face is flush with the interface between the leading edge of the turbine blade and the rest of the turbine blade.

[0016] Preferably, in step S4, the cavity is adapted to the inner flow channel, and a narrow groove adapted to the pressure hose is provided through one end of the cavity facing the bottom of the turbine blade tenon. The pressure hose is arranged along the cavity and extends out of the turbine blade from the narrow groove.

[0017] Preferably, in step S2, the measuring holes are arranged at positions of 25%, 50%, and 75% of the leaf height, respectively.

[0018] Preferably, step S3 includes the following steps:

[0019] Step S3.1: Insert the probe into the connection hole and adhere it.

[0020] Step S3.2: Embed the connecting block into the measuring hole and bond it together;

[0021] Step S3.3: Grind the second end face until it is flush with the wall surface;

[0022] Step S3.4: Insert one end of the pressure-sensing hose into the boss and bond it.

[0023] Step S3.5: Arrange the other end of the pressure hose along the cavity and lead out the turbine blade to connect with the measuring equipment.

[0024] Preferably, the end of the probe furthest from the connecting block is machined with a pressure sensing hole.

[0025] Compared with the prior art, the present invention has the following advantages and technical effects: The main purpose of the present invention is to provide a method for measuring the total pressure of the internal flow channel of a small turbine blade, which is suitable for the leading edge of the blade and solves the problem that the prior art is difficult to measure the total pressure of the internal flow channel of a real turbine blade in the laboratory. When using the method, a real turbine blade is used instead of a magnified model, making the measurement results more realistic and reliable. At the same time, the present invention cuts the turbine blade to be tested, embeds a small-volume total pressure probe between the two cut parts, and then re-bonds them to restore the original shape. This makes the total pressure probe firmly arranged, without affecting the performance of the turbine blade surface or interfering with the original flow field of the internal flow channel.

[0026] Compared with existing total pressure measurement devices, this invention can cut the blade in two at an appropriate distance from the wall of the internal flow channel without film vents, according to specific experimental requirements. Total pressure measurement devices are discretely arranged at the cut surfaces of some blades to achieve simultaneous measurement at multiple points. Moreover, the measurement method has little impact on the original flow field of the film vents on the turbine blade, and the measurement results are accurate and reliable. Attached Figure Description

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

[0028] Figure 1 This is a schematic diagram of the measurement method of the present invention;

[0029] Figure 2 A schematic diagram of turbine blade segmentation for the measurement method of the present invention;

[0030] Figure 3 This is a schematic diagram of the cavity structure of the present invention;

[0031] Figure 4 This is a schematic diagram of the total pressure probe of the present invention;

[0032] Figure 5 This is a schematic diagram of the probe structure of the present invention;

[0033] Figure 6 This is a schematic diagram of the connecting block of the present invention;

[0034] Figure 7 This is a schematic diagram of the pressure-sensing hose of the present invention;

[0035] Figure 8 This is a graph showing the actual measurement data of the present invention;

[0036] In the diagram: 1. Probe; 2. Connecting block; 3. Pressure hose; 4. Turbine blade leading edge; 5. Remaining part of turbine blade; 11. Pressure sensing hole; 21. Connecting hole; 22. Boss; 23. First end face; 24. Second end face; 41. Inner flow channel; 42. Wall; 51. Cavity; 52. Narrow groove. Detailed Implementation

[0037] 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 embodiments of the present invention, and not all embodiments. 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.

[0038] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0039] Reference Figure 1-8 As shown, this embodiment provides a total pressure measurement test method suitable for the internal flow channel of small-sized blades, including the following steps:

[0040] Step S1: Prepare the total pressure probe and select the experimental object. Divide the selected turbine blade into two parts, namely the leading edge part 4 of the turbine blade and the rest of the turbine blade 5.

[0041] Step S2: Process the leading edge portion 4 of the turbine blade, and along the direction of the inner flow channel 41 of the turbine blade, open a measurement hole on the wall 42 that matches the total pressure probe according to the blade height.

[0042] Step S3: Connect the total pressure probe to the leading edge of the turbine blade 4, so that the total pressure probe passes through the measuring hole and connects with the inner flow channel 41;

[0043] Step S4: Process the remaining part 5 of the turbine blade, open a cavity 51 at the cross-section position, extend the other end of the total pressure probe into the cavity 51 and arrange it along the cavity 51, and lead the total pressure probe out of the turbine blade.

[0044] Step S5: Bond the leading edge portion 4 of the turbine blade to the remaining portion 5 of the turbine blade, restoring it to a complete blade state;

[0045] Step S6: Connect the measuring equipment to the part of the total pressure probe that extends out of the turbine blade to conduct a total pressure measurement test of the inner flow channel 41.

[0046] The main objective of this invention is to provide a method for measuring the total pressure of the inner flow channel 41 of a small turbine blade leading edge portion 4, solving the problem that existing technologies make it difficult to measure the total pressure of the inner flow channel 41 of a real turbine blade in the laboratory. When using this method, a real turbine blade is used instead of a magnified model, making the measurement results more realistic and reliable. Furthermore, this invention involves cutting the turbine blade to be tested, embedding a small-volume total pressure probe between the two cut parts, and then re-bonding them to restore the original shape. This ensures the total pressure probe is firmly positioned, without affecting the performance of the turbine blade surface or interfering with the original flow field of the inner flow channel 41.

[0047] Compared with existing total pressure measurement devices, this invention can cut the blade into two at an appropriate position 42 away from the wall surface of the non-film perforated inner flow channel under test, according to specific test requirements. Total pressure measurement devices are discretely arranged at the cut surfaces of some blades to achieve simultaneous measurement at multiple points. Moreover, the measurement method has little impact on the original flow field of the film perforated array measured on the turbine blade, and the measurement results are accurate and reliable.

[0048] Furthermore, when dividing the turbine blade, select a position about 1.5 mm away from the wall surface 42 of the inner flow channel 41 without film gas flow, and divide the blade into two parts: the leading edge part 4 of the turbine blade and the remaining part 5 of the turbine blade.

[0049] Further optimizing the scheme, in step S1, the total pressure probe includes an L-shaped probe 1. One end of the probe 1 extends into the inner flow channel 41 through the measuring hole, and the other end of the probe 1 extends out of the measuring hole and is inserted and fixed on the connecting block 2. The connecting block 2 is adapted to the measuring hole and embedded and fixed in the measuring hole. The end of the connecting block 2 away from the probe 1 is connected to a pressure-sensing hose 3. The end of the probe 1 away from the connecting block 2 is machined with a pressure-sensing hole 11. The first end face 23 of the connecting block 2 extends into the measuring hole and has a connecting hole 21 adapted to the probe 1. The second end face 24 of the connecting block 2 away from the probe 1 is fixed with a cylindrical boss 22, and the pressure-sensing hose 3 is inserted and fixed in the boss 22. The first end face 23 is flush with the interface between the measuring hole and the inner flow channel 41, and the second end face 24 is flush with the interface between the leading edge of the turbine blade 4 and the rest of the turbine blade 5. A set of probes 1, connecting blocks 2, and a pressure-sensing hose 3 is fixed to the measuring hole position on the blade surface. When fixing the probe 1, it should be aligned with the connecting block 2, facing the expected flow direction, to measure the total pressure value of the inner flow channel 41. The diameter of the probe 1 can be selected according to the specific size of the inner flow channel 41 of the turbine blade being measured, but generally does not exceed 3mm. The inner chamfer of the pressure sensing hole 11 is 30°-90°, and the inner diameter is 0.2mm-1mm. The connecting block 2 is 3D printed in one piece, and its main body shape is generally a simple polygon. The first end face 23 on one side is machined for the connecting hole 21 for mounting the probe 1, and the second end face 24 on the other side is machined for connecting the pressure-sensing hose 3. The hollow cylindrical boss 22 of the pressure hose 3, the first end face 23 and the second end face 24 on both sides should be as smooth as possible to ensure a continuous transition with the inner and outer surfaces of the turbine after the connecting block 2 is installed. The connecting block 2 has two main functions: firstly, it serves as a transition connection between the probe 1 and the pressure hose 3; secondly, it serves to position and orient the total pressure probe. The first end face 23 of the connecting block 2 is 3D printed to the shape of the inner flow channel 41 at the measured position, and the second end face 24 is 3D printed to the shape of the blade surface at the measured position. The fixed installation orientation of the probe 1 needs to be matched with the connecting block 2 so that after the measuring device is installed, the probe 1 is directly facing the mainstream direction of the inner flow channel of the turbine blade.

[0050] In this embodiment, the main body of the connecting block 2 is a small square block of 2.5mm×2.5mm. The specific thickness is determined by the thickness of the turbine blade at the measured position. The boss 22 has a height of 2.5mm, an outer diameter of 2mm, a wall thickness of 0.25mm, an outer diameter of 1.5mm for the pressure hose 3, and a diameter of 0.8mm for the connecting hole 21.

[0051] Further optimizing the scheme, in step S4, the cavity 51 is adapted to the inner flow channel 41. A narrow groove 52 adapted to the pressure-sensing hose 3 is opened through one end of the cavity 51 facing the bottom of the turbine blade tenon. The pressure-sensing hose 3 is arranged along the cavity 51 and extends out of the turbine blade from the narrow groove 52. In this embodiment, the cavity 51 is used as a channel for the flow-sensing hose, with a depth of 5mm and a width and height similar to the inner flow channel 41 of the turbine blade being tested. At the bottom of the cavity 51, near the center side of the blade, a narrow groove 52 is machined with a depth of 5mm and a width that is 0.5mm wider than the outer diameter of the pressure-sensing hose 3. The length extends to the bottom of the turbine blade tenon. The pressure-sensing hose 3 is arranged and placed in the narrow groove 52 and leads out from the bottom of the turbine blade tenon.

[0052] To further optimize the scheme, in step S2, the measuring holes are arranged at positions of 25%, 50%, and 75% of the blade height, respectively. The shape and size of the measuring holes are adapted to the main body of the connecting block 2, and during measurement, the main body of the connecting block 2 is embedded in the connecting hole 21.

[0053] Further optimization of the solution, step S3 includes the following steps:

[0054] Step S3.1: Insert probe 1 into the connecting hole 21 and glue it in place; insert probe 1 into the through hole connecting hole 21 of connecting block 2 and glue it firmly with a small amount of silicone. Probe 1 should be facing the main flow direction of the internal flow channel. The main body of connecting block 2 is square, so probe 1 and connecting block 2 need to be adjusted in the correct direction before they are joined together.

[0055] Step S3.2: Embed the connecting block 2 into the measuring hole and bond it; after the silicone bonding part in the previous step has dried and become firm, insert the probe 1 into the inner flow channel 41, and embed the main body of the connecting block 2 into the measuring hole and bond it with a small amount of silicone.

[0056] Step S3.3: Grind the second end face 24 to be flush with the wall surface 42; use fine sandpaper to grind the main side of the connecting block 2, that is, the part that fits with the turbine blade opening wall surface 42, to reduce the protrusion inside the impeller and reduce the impact on the blade performance.

[0057] Step S3.4: Insert one end of the pressure-sensing hose 3 into the boss 22 and bond it; after the silicone bonding part in the previous step has dried and become firm, insert the pressure-sensing hose 3 into the hollow cylindrical boss 22 of the connecting block 2, bond it with a small amount of silicone, and ensure that the pressure-sensing hose 3 is connected to the probe 1.

[0058] Step S3.5: Arrange the other end of the pressure-applying hose 3 along the cavity 51, leading out the turbine blade and connecting it to the measuring equipment. After the silicone adhesive in the previous step has dried and become firmly bonded, the pressure-applying hose 3 can be arranged in sequence within the cavity 51 of the remaining part 5 of the turbine blade, and then led out of the blade through the narrow groove 52.

[0059] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0060] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A test method for measuring total pressure in the internal flow channel of small-sized blades, characterized in that... Includes the following steps: Step S1: Prepare the total pressure probe and select the experimental object. Divide the selected turbine blade into two parts, namely the leading edge part of the turbine blade (4) and the rest of the turbine blade (5). Step S2: Process the leading edge portion (4) of the turbine blade, and along the direction of the inner flow channel (41) of the turbine blade, open a measurement hole on the wall (42) that matches the total pressure probe according to the blade height; Step S3: Connect the total pressure probe to the leading edge of the turbine blade (4), so that the total pressure probe passes through the measuring hole and connects with the inner flow channel (41); Step S4: Process the remaining part of the turbine blade (5), open a cavity (51) at the cross-section position, extend the other end of the total pressure probe into the cavity (51) and arrange it along the cavity (51), and lead the total pressure probe out of the turbine blade; Step S5: Bond the leading edge portion (4) of the turbine blade to the remaining portion (5) of the turbine blade to restore it to a complete blade state; Step S6: Connect the measuring device to the part of the total pressure probe that leads out of the turbine blade to conduct a total pressure measurement test of the inner flow channel (41); In step S1, the total pressure probe includes an L-shaped probe (1). One end of the probe (1) extends into the inner flow channel (41) through the measuring hole, and the other end of the probe (1) extends out of the measuring hole and is inserted and fixed on the connecting block (2). The connecting block (2) is adapted to the measuring hole and embedded and fixed in the measuring hole. The end of the connecting block (2) away from the probe (1) is connected to a pressure-sensing hose (3). The first end face (23) of the connecting block (2) extends into the measuring hole and has a connecting hole (21) that is compatible with the probe (1). A cylindrical boss (22) is fixed to the second end face (24) of the connecting block (2) away from the probe (1). The pressure hose (3) is inserted and fixed in the boss (22). The first end face (23) is flush with the interface between the measuring hole and the inner flow channel (41). The second end face (24) is flush with the interface between the leading edge portion (4) of the turbine blade and the remaining portion (5) of the turbine blade.

2. The total pressure measurement test method for the internal flow channel of small-sized blades according to claim 1, characterized in that: In step S4, the cavity (51) is adapted to the inner flow channel (41), and a narrow groove (52) adapted to the pressure hose (3) is opened through one end of the cavity (51) facing the bottom of the turbine blade tenon. The pressure hose (3) is arranged along the cavity (51) and extends out of the turbine blade from the narrow groove (52).

3. The total pressure measurement test method for the internal flow channel of small-sized blades according to claim 1, characterized in that: In step S2, the measuring holes are respectively arranged at positions of 25%, 50% and 75% of the blade height.

4. The total pressure measurement test method for the internal flow channel of small-sized blades according to claim 1, characterized in that: Step S3 includes the following steps: Step S3.1: Insert the probe (1) into the connection hole (21) and adhere it; Step S3.2: Embed the connecting block (2) into the measuring hole and bond it; Step S3.3: Grind the second end face (24) to be flush with the wall surface (42); Step S3.4: Insert one end of the pressure-sensing hose (3) into the boss (22) and bond it; Step S3.5: Arrange the other end of the pressure hose (3) along the cavity (51) to lead out the turbine blade and connect it to the measuring equipment.

5. The total pressure measurement test method for the internal flow channel of small-sized blades according to claim 1, characterized in that: The probe (1) has a pressure sensing hole (11) at the end away from the connecting block (2).

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