Method of manufacturing turbine blade for turbine engine

Abstract

The invention relates to a method for manufacturing a turbine blade for a turbine engine, comprising the steps of machining a blade blank (10A) by casting, the blade blank (10A) having an outer surface (18) and an inner surface (20) defining a cooling cavity (22), and drilling ports (28) from the outer surface of the blade blank to the inner cavity thereof at predefined drilling regions (24). In the forming step, convex elements (26) are formed on the outer surface of the blade blank, each convex element being located in the drilling region. In the machining step, the protruding element is completely removed from the drilled port.

Description

Technical Field

[0001] This invention relates to the field of turbine blades for turbine engines, and more specifically, to the manufacture of blades.

[0002] More specifically, this invention relates to a method for manufacturing turbine blades for a turbine engine. Technical Background

[0003] Typically, turbine blades in a turbofan engine are equipped with internal cooling circuits, enabling the blades to withstand the extremely high temperatures they experience during turbofan engine operation. The blades have aerodynamic walls extending between the blade root and the blade tip.

[0004] The cooling circuit includes:

[0005] o A cooling cavity defined by the inner surface of the blade wall, and

[0006] The port that passes through the wall and connects the blade cavity to the airflow passage allows hot air from the turbine combustion chamber of the turbine engine to circulate within it.

[0007] Cooling blades are achieved by introducing cooling air into the blade cavity through its root, and then expelling the air from the cavity through ports on the wall into the airflow channel. These ports allow both the supply of cooling air into the cavity and the cooling of the blade wall as the air passes through.

[0008] Typically, turbine blades are manufactured using the following methods:

[0009] o The first step of forming the blade blank 10A by casting, and

[0010] The second step, as shown in Figure 1, involves drilling a port 28 through the wall 12 of the blade blank 10A to its inner cavity 22 using a drilling device 30. The drilling location is within a predetermined drilling area 24.

[0011] Determining the actual location of each drilled area 24 on the outer surface 18 of the blade blank 10A includes the following steps:

[0012] The theoretical location of each drilled region 24 was determined through thermal studies of the blades to achieve optimal cooling performance.

[0013] o Relative to the six-point reference system of the blade blank 10A, the theoretical position of each drilled area 24 is transferred to the outer surface 18 of the blade blank 10A.

[0014] However, the location of the reference points may change due to manufacturing tolerances of the blade blank wall or during rework on the outer surface of the blade blank. Therefore, modifying the location of at least one reference point will cause a deviation between the actual and theoretical positions of the drilled area on the outer surface of the blade blank, resulting in inaccurate port positioning on the outer surface of the blade. Inaccurate port positioning will impair the cooling effect of the cooling circuit on the blade. Furthermore, drilling in inaccurate areas may cause impact on the inner surface of the blade blank wall, thereby damaging the wall. Summary of the Invention

[0015] This invention provides a solution to the above-mentioned problems by providing a turbine blade manufacturing method that includes a novel casting and forming step.

[0016] The first aspect of the present invention relates to a method for manufacturing turbine blades for a turbine engine, comprising the following steps:

[0017] The blade blank is formed by casting, the blade blank having an outer surface and an inner surface defining a cooling cavity, and

[0018] o The blade blank is machined by drilling ports from the outer surface of the blade blank into its inner cavity in a predefined drilling area.

[0019] During the forming step, protruding elements are formed on the outer surface of the blade blank, each protruding element being located in a drilled area.

[0020] The manufacturing method according to a first aspect of the invention allows for marking of drilled areas by forming protruding elements on the outer surface of the blade blank. During the machining process, the protruding elements are subsequently inspected and completely removed by a machine tool. This method of manufacturing blade blanks eliminates any discrepancy between the actual and theoretical positions of each drilled area, thereby ensuring the correct positioning of the blade inlet and consequently guaranteeing the cooling effect of the turbine blade.

[0021] In the first alternative to the machining step, drilling is performed by electrical discharge machining.

[0022] According to the second alternative to the processing steps, the port is drilled out by laser during the processing steps.

[0023] Advantageously, the manufacturing method includes an additional step of applying at least one coating layer to the outer surface of the blade blank, said step of applying at least one coating layer being performed after the step of machining the blade blank. This feature avoids any damage to the coating during the machining step.

[0024] Advantageously, according to a second embodiment of the manufacturing method, the first coating is an anti-corrosion coating and the second coating is a thermal barrier coating.

[0025] A second aspect of the invention relates to a turbine blade blank for a turbine engine, comprising an outer surface and an inner surface defining a cooling cavity. The blade blank includes protruding elements distributed on its outer surface, each protruding element forming a drilled area of ​​the blade blank.

[0026] According to the second aspect of the invention, the blade blank has protruding elements on its outer surface, which enable the marking of the drilling area of ​​the blade blank.

[0027] According to the first embodiment of the blade blank, each protruding element has a hemispherical shape.

[0028] According to a second embodiment of the blade blank, each protruding element has a cylindrical rod shape. This geometrically shaped protruding element guides the drilling device by indicating the drilling direction during a machining step of the manufacturing method, in which the protruding element is completely removed.

[0029] A third aspect of the invention relates to a high-pressure turbine for a turbine engine, comprising blades obtained by a manufacturing method according to a first aspect of the invention.

[0030] A better understanding of the invention and its various applications will be gained by reading the following description and examining the accompanying drawings. Attached Figure Description

[0031] Further advantages and features of the invention will become apparent from the following description illustrated in the accompanying drawings:

[0032] Figure 1, as previously described, is a partial schematic cross-sectional view of a turbine blade blank during the processing steps of a turbine blade manufacturing method according to the prior art;

[0033] Figure 2 is a schematic cross-sectional view of a turbine blade blank according to the first embodiment of the blade blank;

[0034] Figure 3 is a partial schematic perspective view of the turbine blade blank shown in Figure 2;

[0035] Figure 4 is a schematic cross-sectional view of a turbine blade blank according to the second embodiment of the blade blank;

[0036] Figure 5 is a partial schematic cross-sectional view of a turbine blade blank according to the first embodiment of the blade blank during the processing steps of the turbine blade manufacturing method;

[0037] Figure 6 is a partial schematic cross-sectional view of a turbine blade blank according to the second embodiment of the blade blank during the processing steps of the turbine blade manufacturing method.

[0038] Figure 7 is a partial schematic perspective view of a turbine blade after the machining steps in the turbine blade manufacturing process. Detailed Implementation

[0039] An exemplary embodiment of the turbine blade manufacturing method according to the present invention will now be described in detail with reference to the accompanying drawings. This example illustrates the features and advantages of the present invention.

[0040] Unless otherwise stated, the same element appearing in different figures has a single reference numeral.

[0041] To understand this invention, the XYZ orthogonal reference frame shown in the figure will be used, where the X and Y axes extend in a horizontal plane, and the Z axis extends in a vertical plane, with directions as shown in the figure. The direction from the root to the tip of the turbine blade is oriented along the Z axis of the XYZ reference frame.

[0042] The manufacturing method of turbine blade 10B includes:

[0043] o The first step of forming the blade blank 10A by casting, and

[0044] o The second step of machining the blade blank 10A by drilling.

[0045] Figures 2, 3, and 4 illustrate the blade blank 10A obtained through the forming steps of the manufacturing method. The blade blank 10A corresponds to the as-cast component, which includes:

[0046] An aerodynamic wall 12 extends between the blade root 14 and the blade tip 16 of the blade blank 10A, the wall 12 being defined by an outer surface 18 and an inner surface 20.

[0047] o The cooling cavity 22 defined by the inner surface 20, and

[0048] The protruding elements 26 are distributed on the outer surface 18, each protruding element forming a drilled area 24 of the blade blank 10A.

[0049] The wall 12 and the protruding element 26 are formed simultaneously in a single step of forming the blade blank 10A.

[0050] The positioning of each drilled region 24 on the outer surface 18 of the blade blank 10A needs to be determined by thermal studies of the blade 10B to obtain the best cooling effect for the blade 10B.

[0051] The steps for forming the blade blank 10A by casting include the following sub-steps:

[0052] o To manufacture a wax model of the replica blade blank 10A (i.e., wall 12 with protruding element 26),

[0053] o Create a mold around the wax model, such as a ceramic mold, and

[0054] o Pour metal into the mold.

[0055] Each protruding element 26 is formed by locally adding extra material at one of the drilled regions 24 to mark the actual location of the drilled region 24.

[0056] According to a first embodiment of the blade blank 10A, as shown in Figures 2 and 3, each protruding element 26 has a hemispherical shape.

[0057] According to a second embodiment of the blade blank 10A, as shown in FIG. 4, each protruding element 26 has a cylindrical rod 262. Each cylindrical rod 262 forms an angle α1 in the YZ plane relative to the outer surface 18 of the blade blank 10A. The value of angle α1 varies depending on the row position of the protruding element 26 on the blade blank 10A. For example, for rows located in the upper region of the blade blank 10A, angle α1 is approximately equal to 90°, and for other rows, it is between 0° and 45°.

[0058] Furthermore, according to a variation of the second embodiment (not shown), each cylindrical rod 262 may form an angle α2 in the XY plane and / or an angle α3 in the XZ plane relative to the outer surface 18 of the blade blank 10A. For example, angle α2 is approximately equal to 45°.

[0059] Figures 5 and 6 illustrate the steps of machining the blade blank 10A by drilling a port 28 in the blade blank 10A using a drilling device 30. The drilling location is at the protruding element 26 forming the drilling area 24 and leads to the cavity 22 of the blade blank 10A. In the machining step, the drilling device 30 is directly arranged on one of the protruding elements 26 to completely remove the protruding element 26 and form a port 28 at the drilling area 24.

[0060] The drilling device 30 is, for example, a laser processing tool or an electrical discharge machining (EDM) tool. The processing steps include a sub-step of calibrating the drilling device 30 according to the protruding element 26 of the blade blank 10A before drilling out of the port 28.

[0061] During the step of processing the blade blank 10A according to its first embodiment, as shown in FIG5, when the drilling device 30 is arranged on the protruding element 26 of the hemispherical 260, it can be oriented at different angles relative to the outer surface 18 (the drilling device 30 is schematically represented by solid and dashed lines).

[0062] During the step of machining the blade blank 10A according to its second embodiment, as shown in FIG6, when the drilling device 30 is arranged on the protruding element 26 of the cylindrical rod 262, it is oriented relative to the outer surface 18 at angles α1, α2, and α3. This geometry of the protruding element 26 can guide the drilling device 30 by indicating the drilling direction of the wall 12 of the blade blank 10A.

[0063] Figure 7 shows a turbine blade 10B of a turbine engine, which, after the processing steps of the manufacturing method, includes a plurality of ports 28, each arranged on one of the drilled areas 24, replacing one of the protruding elements 26 of the blade blank 10A.

[0064] A turbine blade 10B for a turbine engine comprises at least one coating applied to its outer surface 18. According to a specific example of blade 10B, blade 10B comprises a first coating applied directly to its outer surface 18 and a second coating applied on top of the first coating. Advantageously, the first coating is an anti-corrosion coating, and the second coating is a thermal barrier coating. Therefore, the method of manufacturing blade 10B includes the additional step of applying the coating.

[0065] The coating process is performed after the step of machining the blade blank 10A.

[0066] According to the manufacturing method of the present invention, by forming a protruding element 26 on the outer surface 18 of the blade blank 10A during the forming step, the correct positioning of the port 28 during the machining step is ensured. Therefore, the position of each port 28 of the blade 10B obtained by this manufacturing method corresponds to the actual position of the drilling region 24, that is, the position where the optimal cooling effect of the blade 10B can be achieved.

Claims

1. A manufacturing method of a turbine blade (10B) for a turbine engine, comprising the steps of: forming a blade blank (10A) by casting, said blade blank (10A) having an outer surface (18) and an inner surface (20) defining a cooling cavity (22), and machining the blade blank (10A) using a drilling device to drill a port (28) from the outer surface of the blade blank into its inner cavity (22) in a predefined drilling area (24), characterized in that, during said forming step, the drilling of the port (28) completely removes a protruding element (26); said protruding element (26) is formed on the outer surface (18) of the blade blank (10A), each protruding element (26) being located within the drilling area.

2. The production method according to claim 1, characterized by, During said machining step, the drilling of the port (28) is performed by electrical discharge machining.

3. The production method according to claim 1, characterized by, During said machining step, the drilling of the port (28) is performed by laser.

4. The production method according to any one of claims 1 to 3, characterized by: it comprises an additional step of applying at least one coating to the outer surface (18) of the blade blank (10A), and said step of applying at least one coating is performed after the step of machining the blade blank (10A).

5. A turbine blade blank (10A) for a turbine engine comprising an outer surface (18) and an inner surface (20) defining a cooling cavity (22), characterized in that, it comprises protruding elements (26) distributed on its outer surface (18), each protruding element (26) forming a drilling area (24) of said blade blank (10A).

6. The turbine blade blank (10A) for a turbine engine of claim 5, characterized in that, Each protruding element (26) has a semi-spherical shape (260).

7. The turbine blade blank (10A) for a turbine engine of claim 5, characterized in that, Each protruding element (26) has a cylindrical stem (262).

8. A high-pressure turbine for a turbine engine comprising a blade (10B) obtained according to the manufacturing method of any one of claims 1 to 4.

Images