A special fixture for measuring air flow of fir-tree turbine blade

Abstract

A special fixture for measuring the airflow of fir tree-shaped turbine blades belongs to the technical field of tooling structures for measuring the airflow of fir tree-shaped turbine blades. It includes a pressure cap for connecting to an airflow testing device, a transition section installed in the central hole of the pressure cap, a sealing block installed in the central hole of the transition section, a cover plate for clamping the turbine blade on the top of the transition section, and a plug installed at the tenon cavity end of the turbine blade. This airflow fixture can accurately obtain the mass flow rate of the air in the internal cooling channels of the turbine blade without leakage, allowing for the inspection of the casting condition of the blade's internal cavity and the drilling condition of the film cooling holes, providing a basis for selecting blades for installation.

Description

Technical Field

[0001] This invention belongs to the technical field of tooling structure for measuring airflow of fir tree-shaped turbine blades, specifically relating to a special fixture for measuring airflow of fir tree-shaped turbine blades. Background Technology

[0002] Turbine blades have complex internal structures and are covered with film cooling pores, making them susceptible to various influences. Water flow rate testing is typically used to inspect the casting quality of the blade's internal structure and the drilling of the film cooling pores. However, after the blades are installed, the testing medium is air, and water flow rate readings cannot accurately reflect the blade's condition after installation. Therefore, air flow rate testing technology has become a crucial step in verifying blade quality. This invention designs a specialized fixture to meet the air flow rate testing requirements for turbine blades. Summary of the Invention

[0003] The purpose of this invention is to provide a special fixture for measuring the airflow of fir tree-shaped turbine blades. The airflow fixture with this structure can accurately obtain the air mass flow rate of the internal cooling channel of the turbine blade without leakage, so as to inspect the casting condition of the blade cavity and the drilling condition of the film cooling hole, and provide a basis for selecting the blades to be installed.

[0004] A special fixture for measuring the airflow of a fir-shaped turbine blade includes a gland for connecting to an airflow tester, an adapter section installed in the center hole of the gland, a sealing block installed in the center hole of the adapter section, a cover plate for pressing the turbine blade on the top of the adapter section, and a plug installed at the tenon cavity end of the turbine blade.

[0005] The cover is a disc-shaped structure with a boss at one end. The upper surface edge of the base of the cover is machined with a slope to prevent air leakage when entering the cover. The center of the cover is machined with a mounting hole for installing the adapter section.

[0006] The upper surface of the gland boss is machined with an annular groove located outside the central hole, and an O-ring for sealing the connection between the gland and the transition section is installed in the groove.

[0007] The transition section is a cylindrical structure with a central groove. The top outer circular surface of the cylindrical structure is provided with an edge, and the edge is provided with connecting holes at equal intervals along the circumference. An elongated groove is machined at the bottom of the groove.

[0008] The cover plate has a circular shape, with waist-shaped holes machined at equal intervals along the circumference of the edge of the cover plate. One end face of the cover plate is machined with a groove for mating with the sealing block, and the other end face of the cover plate is machined with a profile for mating with the contact part of the blade edge plate.

[0009] The sealing block is provided with a draft angle along its outer shape so that it can be installed into the transition section and completely seal off the air. The center of the sealing block is machined with a profile that matches the tenon profile of the turbine blade.

[0010] The technical effects of this invention are as follows:

[0011] This tooling structure can be used for airflow testing of various turbine blades. The disc base is adapted to various airflow testers. The oil-resistant rubber sealing block can effectively seal the surfaces of the blade teeth, and the cover plate can press the blade edge plate according to its shape.

[0012] This invention designs a special fixture for measuring the airflow of turbine blades. Through a reasonable tooling structure and a complete sealing system, it accurately measures the air mass flow rate of the blades. Compared with water flow measurement data, it can better meet the testing requirements after the blades are installed and satisfy the design department's requirements for selecting blades for installation. Attached Figure Description

[0013] Figure 1 Three-dimensional diagram of a special fixture for measuring airflow from fir tree-shaped turbine blades;

[0014] Figure 2 A schematic cross-sectional view of the special fixture for measuring airflow from fir tree-shaped turbine blades according to the present invention;

[0015] Figure 3 Top view of the pressure cap of the special fixture for measuring airflow of fir tree-shaped turbine blades according to the present invention;

[0016] Figure 4 The present invention Figure 3 A schematic diagram of direction AA;

[0017] Figure 5 A top view of the adapter section of the special fixture for measuring airflow from fir tree-shaped turbine blades according to the present invention;

[0018] Figure 6 The present invention Figure 5 BB-direction diagram;

[0019] Figure 7 A schematic diagram of the cover plate of the special fixture for measuring airflow of fir tree-shaped turbine blades according to the present invention;

[0020] Figure 8 The present invention Figure 7 CC-direction schematic diagram;

[0021] Figure 9 The present invention Figure 7 DD-direction schematic diagram;

[0022] Figure 10 A schematic diagram of the sealing block of the special fixture for measuring airflow of fir tree-shaped turbine blades according to the present invention;

[0023] Figure 11 The present invention Figure 10 EE direction diagram;

[0024] Figure 12 A blocked top view of the special fixture for measuring airflow from fir tree-shaped turbine blades according to the present invention;

[0025] Figure 13 A blocked front view of the special fixture for measuring airflow from fir tree-shaped turbine blades according to the present invention;

[0026] Figure 14 A schematic diagram of the tenon-tooth cavity of the fir-shaped turbine blade of the present invention;

[0027] 1-Gland, 2-Adapter section, 3-Cover plate, 4-O-ring, 5-Washer, 6-Shouldered hexagonal nut, 7-Equal length double-ended stud, 8-Sealing block, 9-Plug, 10-Bevel, 11-Edge, 12-Elongated groove, 13-Oval hole. Detailed Implementation

[0028] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0029] like Figures 1 to 14 As shown, a special fixture for measuring the airflow of a fir-shaped turbine blade includes a pressure cap 1 for connecting to an airflow testing device. The pressure cap 1 is made of 1Cr18Ni9Ti material and is a disc-shaped structure with a boss at one end. The upper surface edge of the base of the pressure cap 1 is machined with a slope 10 to prevent air leakage when entering the pressure cap 1, and the slope 10 is 22°. The center of the pressure cap 1 is machined with a mounting hole for installing a transition section 2. Equal-length double-ended studs 7 are screwed to the top of the boss of the pressure cap 1 at equal intervals. In this embodiment, the airflow testing device used is a Swiss airflow testing device, and the flow testing interface of this airflow testing device is equipped with an inner diameter of... The clamping ring, therefore, in this embodiment, the outer diameter of the base of the pressure cap 1 is [missing information]. The inner diameter of the disc and the cover 1 is determined based on the size of the tenon teeth of the turbine blade, the outer diameter of the tenon sealing block 8, and the outer diameter of the transition section 2; the special clamp for air flow is installed by fitting the cover 1 with the tight ring of the air flow tester. An adapter section 2 is installed in the central hole of the pressure cap 1. In this embodiment, the adapter section 2 is specifically: the adapter section 2 is a cylindrical structure with a central groove. The cylindrical structure is machined by straight cutting to facilitate clamping. The outer circular surface of the top of the cylindrical structure is provided with an edge 11. Four threaded holes are equally spaced along the circumference of the edge 11 for connecting with the cover plate 3. The upper surface of the protrusion of the pressure cap 1 is machined with an annular groove located outside the central hole. An O-ring 4 for sealing the connection between the pressure cap 1 and the adapter section 2 is installed in the groove. An elongated groove 12 is machined at the bottom of the groove. The cylindrical part of the adapter section 2 is inserted into the mounting hole of the pressure cap 1. The elongated groove 12 is opened in the adapter section 2 to facilitate air circulation. The material of the adapter section 2 is 45#. A sealing block 8 is installed in the center hole of the transition section 2. In this embodiment, the sealing block 8 is specifically designed with a 5° draft angle along its outer shape to allow it to be inserted into the transition section 2 and completely seal off the air. The sealing block 8 is used to seal the turbine blade tenons, ensuring that all surfaces of the tenons are completely sealed and that there is no leakage during airflow testing. In this embodiment, the sealing block 8 is made of oil-resistant rubber with a Shore hardness of 40-45. A turbine blade with a suitable tenon size is selected as the mold. After casting and cooling the blade tenon, the sealing block 8 of the fixture is obtained. The sealing block 8 made of this material has a certain degree of toughness, which facilitates the clamping of the tenons and prevents deformation during use. The top of the transition section 2 is equipped with a cover plate 3 for pressing the turbine blades, and a gasket 5 is provided between the cover plate 3 and the sealing block 8. In this embodiment, the cover plate 3 is specifically: the cover plate 3 has a circular shape, and the edge of the cover plate 3 is machined with waist-shaped holes 13 at equal intervals along the circumference so that the bolts have a certain amount of movement on the cover plate 3 when pressing. One end face of the cover plate 3 is machined with a groove for cooperating with the sealing block 8, and the other end face of the cover plate 3 is machined with a profile for cooperating with the contact part of the blade edge plate. Since the blade edge plate is a curved structure, the present invention uses a profile digital modeling method to manufacture the contact part between the cover plate 3 and the blade edge plate. After using this method, the curved contact part can be completely fitted to prevent air leakage during the pressing process. The material of the cover plate 3 is 1Cr18Ni9Ti. A plug 9 is installed at the end of the tenon cavity of the turbine blade. When the turbine blade is tested for air flow, in order to prevent air from entering the sealed cavity, the plug 9 is directly installed on the cavity that does not require flow testing. The plug 9 is made with a 3° draft angle so that it can completely seal the air when installed in the blade cavity. The material is oil-resistant rubber with a Shore hardness of 40-45.

[0030] A method for using a special fixture for measuring airflow from fir tree-shaped turbine blades includes the following steps:

[0031] Install the plug 9 onto the turbine blade cavity where flow testing is not required; install the turbine blade with the plug 9 into the sealing block 8 located at the transition point, at which point the tenon of the turbine blade is wrapped inside the sealing block 8; insert the cover plate 3 so that the profile of the cover plate 3 matches the blade edge plate; finally, screw the shouldered hexagonal nut 6 onto the equal-length double-ended stud 7 so that the cover plate 3 presses against the turbine blade edge plate.

Claims

1. A special fixture for measuring the airflow of fir tree-shaped turbine blades, characterized in that, The device includes a gland for connection with an air flow tester. The gland is a disc-shaped structure with a boss at one end. The center of the gland is machined with a mounting hole for installing an adapter section. The adapter section is a cylindrical structure with a groove in the center. An elongated groove is machined at the bottom of the groove. A sealing block is installed in the groove of the adapter section. The center of the sealing block is machined with a profile that matches the tenon profile of the turbine blade, so that the tenon of the turbine blade is wrapped inside the sealing block. The top of the transition section is fitted with a cover plate for pressing the turbine blades, and a plug is installed at the tenon cavity end of the turbine blade.

2. The special fixture for measuring airflow of fir tree-shaped turbine blades according to claim 1, characterized in that: The upper surface edge of the base of the gland is machined with a slope to prevent air leakage when it enters the gland.

3. A special fixture for measuring airflow of fir tree-shaped turbine blades according to claim 1, characterized in that: The upper surface of the gland boss is machined with an annular groove located outside the central hole, and an O-ring for sealing the connection between the gland and the transition section is installed in the groove.

4. A special fixture for measuring airflow of fir tree-shaped turbine blades according to claim 1, characterized in that: The top outer circular surface of the transition section cylindrical structure is provided with an edge, and connecting holes are opened at equal intervals along the circumference of the edge.

5. A special fixture for measuring airflow of fir tree-shaped turbine blades according to claim 1, characterized in that: The cover plate has a circular shape, with waist-shaped holes machined at equal intervals along the circumference of the edge of the cover plate. One end face of the cover plate is machined with a groove for mating with the sealing block, and the other end face of the cover plate is machined with a profile for mating with the contact part of the blade edge plate.

6. A special fixture for measuring airflow of fir tree-shaped turbine blades according to claim 1, characterized in that: The sealing block is provided with a draft angle along its outer shape so that it can be inserted into the transition section and completely seal off the air.

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