RU219757U1 - INTERBLADED PLATFORM FOR FAN DISC - Google Patents

Abstract

The utility model relates to aircraft engine building, namely to interblade pads for supporting disks of turbomachine fan blades. The technical result of the presented design of the platform is to increase the efficiency of the platform by reducing the deformation of the platform when foreign objects get into adjacent blades without increasing the mass of the platform itself. This is achieved due to the fact that deformation of the central part of the platform is excluded due to its execution in the form of an inclined surface expanding along the movement of the air flow, as well as due to the implementation of the first and second side hangers with a thickness which allows to reduce the load on the fan disk, and due to the presence of a radial rib, which works as an additional stiffener, preventing the central part of the platform from deformation under the influence of centrifugal forces, and working as a fastening element of the platform, capable of holding the platform in the fan disk when foreign objects get in. 3 ill.

Description

The utility model relates to aircraft engine building, namely to interblade pads for supporting disks of turbomachine fan blades.

A turbomachine fan interblade platform is known, containing a plate and two side ribs extending from one face of the specified plate (US Patent US 20140003949 dated 06/25/2013, IPC F01D 11/008, publ. 01/02/2014).

The disadvantage of this platform is the low reliability of the fastening of the platform between adjacent blades due to the fastening of the platform only due to three radial flanges.

Known interscapular platform containing a wall of elongated shape, made with the ability to pass between two fan blades, and this wall contains an aerodynamic outer surface and an inner surface on which is located a locking bracket, made with the possibility of attachment to the fan disk (French Patent FR 3107923 dated 03.03. 2020, IPC F01D 5/30, published 09/10/2021).

The disadvantage of this platform design is the low structural strength of the platform itself, associated with the presence of mounting holes on the aerodynamic surface for mounting the bracket using fasteners. In this case, under the influence of aerodynamic forces, deformation of the holes and the formation of cracks in zones with a weak cross section are possible.

The closest is the interblade platform for the fan disk, containing the first and second side hangers, the central part, on the inside of which stiffeners are made, passing in the direction along the air flow, and fastening elements that serve to place the platform between adjacent blades (RF Patent No. 2299992 dated July 30, 2004. IPC F01D 5/22, published May 27, 2007 Bull. No. 15).

The disadvantage of this design is the increased load on the fan disk when installing the platform, associated with a significant thickness of the central part and side shoulders, which increases the risk of destruction of the fan disk.

The technical result of the presented design of the platform is to increase the efficiency of the platform by reducing the deformation of the platform when foreign objects get into adjacent blades without increasing the mass of the platform itself. This is achieved due to the fact that deformation of the central part of the platform is excluded due to its execution in the form of an inclined surface expanding along the movement of the air flow, as well as due to the implementation of the first and second side hangers with a thickness which allows to reduce the load on the fan disk, and due to the presence of a radial rib, which works as an additional stiffener, preventing the central part of the platform from deformation under the influence of centrifugal forces, and working as a fastening element of the platform, capable of holding the platform in the fan disk when foreign objects get in.

The technical result is achieved by the fact that the interblade platform for the fan disk, containing the first and second side hangers, the central part, on the inside of which stiffening ribs are made, passing in the direction along the air flow, and fastening elements that serve to place the platform between adjacent blades, in In contrast to the known, the central part is made in the form of an inclined surface expanding along the movement of the air flow, and the central part additionally contains a radial protrusion directed towards the fan disk and coupled with stiffeners, the radial protrusion is provided with an axial rib directed along the axis of the disk towards the air inlet. flow, and the above-mentioned rib has a wedge-shaped shape in longitudinal section, expanding along the air flow towards the radial protrusion, and the thickness of the first and second side shoulders is

where h _n12 - the thickness of the first and second side hangers;

h _cp - thickness of the central part of the platform.

Fig. 1 - interscapular platform;

fig. 2 - section A-A of Fig. 1;

fig. 3 is a top view of the interscapular platform.

In the figures, positions are shown:

1 - interscapular platform;

2 - fan disk;

3 - blades;

4 - the first side shoulder;

5 - second side shoulder;

6 - the central part of the platform;

7 - stiffeners;

8 - platform fastening elements;

9 - radial protrusion;

10 - axial edge of the radial protrusion;

11 - inner surface of the rib of the radial protrusion;

h _cp - thickness of the central part of the platform;

h _p12 - the thickness of the first and second side hangers.

Interblade platform 1 for the fan disc 2 is installed between adjacent fan blades 3 (Fig. 1).

The platform 1 contains the first 4 and the second 5 side hangers, the central part 6. On the inner part of the central part 6 stiffening ribs 7 are made, passing in the direction along the air flow (Fig. 2). Also, the housing contains fastening elements 8, which serve to place the platform between adjacent blades 3.

The stiffeners 7 are directed perpendicular to the axis of rotation of the disc.

Fasteners 8, stiffeners 7, first 4 and second 5 side hangers of the platform 1 are made in one piece with the central part 6.

The central part 6 is made in the form of an inclined surface, expanding with the movement of the air flow (Fig. 3). The central part 6 additionally contains a radial protrusion 9 directed towards the fan disc. Radial protrusion 9 is associated with stiffeners 7.

The radial protrusion 9 is provided with an axial rib 10 directed along the disk axis towards the airflow inlet. Moreover, the above-mentioned rib 10 has a wedge-shaped shape in the longitudinal section, expanding along the air flow towards the radial protrusion 9. The central part 6 and the radial protrusion 9 with the axial rib 10 are made monolithic.

The implementation of the rib 10 wedge-shaped increases the rigidity of the rib 10 at the junction with the radial protrusion 9, which eliminates the deformation of the rib 10 protrusion 9 under the action of centrifugal forces R _CB . In this case, the inner surface 11 of the rib 10 is located at an angle to the radial protrusion 9.

The presence in the design of the platform 1 of the radial protrusion 9 with the axial rib 10 helps to prevent deformation of the platform under the action of centrifugal forces F _CB , as well as to keep the platform in the fan disk in case of ingress of foreign objects.

The thickness of the first 4 and second 5 side hangers is:

where h _n12 - the thickness of the first and second side hangers;

h _cp - thickness of the central part of the platform.

If the thickness of the first 4 and second 5 hangers is less than 0.6 ⋅ h _cp , then the hangers 4, 5 may be destroyed during fan operation due to impact when foreign objects enter, which leads to a decrease in the resistance to centrifugal forces F _{of the CB} and reduces the performance of platform 1 because of the possibility of their deformation.

If the thickness of the first 4 and second 5 side hangers is more than 1.4 ⋅ h _cp , then this increases the mass of the interblade platform 1, thereby increasing the load on the fan disk 2, which can lead to additional load on the disk 2 and reduce the platform's performance and resource .

The radial protrusion 9 with the rib 10 form an additional fastening element of the platform on the fan disk 2.

The proposed design of the platform 1 makes it possible to securely fasten the platform 1 to the fan disk 2, and also makes it possible to exclude deformation and/or destruction of the platform 1 when foreign objects get in.

The interblade platform forms the contours of the gas-air path between the fan blades 3.

The interblade platform 1 is mounted by fasteners 8 on the fan disc 2 between adjacent blades 3 using axial pins (not shown). In this case, the radial protrusion 9 with the axial rib 10 for mounting the platform 1 enters the annular shoulder of the retaining ring (not shown), which is installed on the fan disk 2. Such fastening of the platform ensures its retention in case of ingress of foreign objects.

Improving platform performance by reducing platform deformation when foreign objects get into adjacent blades without increasing the mass of the platform itself is achieved due to the fact that the interblade platform for the fan disk, containing the first and second side hangers, the central part, on the inside of which stiffening ribs are made, passing in the direction of the air flow, and fastening elements that serve to place the platform between adjacent blades, in contrast to the well-known central part is made in the form of an inclined surface expanding along the air flow, and the central part additionally contains a radial protrusion directed towards the fan disk and coupled with the stiffening ribs, the radial protrusion is provided with a rib directed along the axis of the disk towards the air flow inlet, and the aforementioned rib has a wedge-shaped shape in the longitudinal section, expanding along the air flow towards the radial protrusion, and the thickness of the first and second side shoulders is

where h _nl2 - the thickness of the first and second side hangers;

h _cp - thickness of the central part of the platform.

Claims (4)

An interblade platform for a fan disk, comprising the first and second side hangers, a central part, on the inside of which stiffening ribs are made, passing in the direction along the air flow, and fastening elements used to place the platform between adjacent blades, characterized in that the central part is made in the form of an inclined surface expanding along the air flow, the central part additionally contains a radial protrusion directed towards the fan disk and coupled with stiffeners, the radial protrusion is provided with an axial rib directed along the axis of the disk towards the air flow inlet, and the above-mentioned rib has wedge-shaped in longitudinal section, expanding along the air flow towards the radial protrusion, and the thickness of the first and second side shoulders is where h _p12 - the thickness of the first and second side hangers; h _cf - thickness of the central part of the platform.

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