CN105179028A - Turbine back-bearing-force casing and gate-leaf integrated structure - Google Patents

Abstract

An integrated structure of a turbine rear bearing casing and a rectifying blade cascade, characterized in that, on the basis of not changing the original casing structure, the part between the inner and outer rings of the casing is divided into flow channels and Non-runner part. The part of the support plate and rectifying cascade vane in the flow channel is designed as a blade shape, and the part in the non-flow channel is designed as a regular rectangular parallelepiped for easy processing. Therefore, the whole structure is divided into two major components: 1) The rectifying blade blade-shaped part with the upper edge plate of the blade is welded to the non-blade part with the lower edge plate of the blade through the whole ring flow channel plate to form a rectifying cascade structure component; 2) The original load-bearing receiver frame structure components. The invention realizes the integration of the turbine rear bearing casing and the rectifying blade cascade without greatly changing the structure of the turbine rear bearing casing, the strength of the rear bearing casing, the coordination of deformation and the support rigidity. It has good practical value and broad application prospect in the field of aviation propulsion technology.

Description

Integrated structure of turbine rear bearing casing and rectifying blade cascade

technical field

The invention relates to an integrated structure of a turbine rear bearing casing and a rectifying blade cascade, belonging to the technical field of aviation propulsion.

Background technique

In the current advanced aviation gas turbine engine, an afterburner is usually installed between the turbine and the exhaust nozzle to perform afterburning and afterburning, and continue to increase the thrust after the engine reaches the maximum thrust state. However, the airflow at the outlet of the low-pressure turbine usually cannot meet the requirements of the afterburner for the airflow angle at the outlet of the low-pressure turbine. Therefore, it is necessary to install rectifying blades between the rotor of the low-pressure turbine and the afterburner to rectify the airflow.

The above-mentioned design will cause the rear bearing casing to be moved backward to install additional outlet rectifying vanes, thereby increasing the axial length of the rotor and increasing the bearing support span. Correspondingly, the number of turbine components will be increased, resulting in an increase in engine weight, which is not conducive to improving the thrust-to-weight ratio of the engine.

The integrated design of the rear bearing casing and the rectifying vane cascade is a new structure integrating the turbine rear bearing casing and the final stage rectifying guide vane of the turbine, which not only meets the requirements of the afterburner for the outlet airflow angle of the low pressure turbine, but also It can also achieve the purpose of shortening the axial length of the low-pressure rotor, reducing weight and reducing the number of parts, thereby increasing the thrust-to-weight ratio of the engine.

Contents of the invention

1. Purpose: In view of the above problems, the purpose of this invention is to provide an integrated structural form of the turbine rear bearing casing and the rectifying blade cascade, which can be used without significantly changing the stress, deformation and support stiffness of the turbine rear bearing casing. Under certain circumstances, the integrated structure of the casing and the rectifying blade cascade after the turbine can be realized.

2. Technical solution: The technical solution adopted in the present invention is: adding rectifying cascades on the basis of the traditional turbine rear load-bearing frame, and designing the part of the load-bearing support plate in the flow channel to rectify together with the rectifying cascades in the shape of an airfoil. The whole ring runner plate ensures the shape of the runner and airtightness. In order to avoid the requirement that the rectifying cascade structure has an excessive impact on the strength and radial rigidity of the rear bearing casing, a special "cantilever" blade structure is adopted in which the upper edge of the blade is fixed and the lower edge is fixed axially and circumferentially.

The present invention is an integrated structural form of the turbine rear bearing casing and the rectifying blade cascade. The section between the rings is divided into runner and non-runner sections. The part of the support plate and rectifying cascade vane in the flow channel is designed in the shape of a blade, and the part in the non-flow channel is designed in a regular rectangular parallelepiped shape for easy processing. Therefore, the whole structure is divided into two major components: 1) The rectifying blade blade-shaped part with the upper edge plate of the blade is welded to the non-blade part of the rectifying cascade with the lower edge plate of the blade through the rectifying runner plate to form a rectifying cascade structure Components; 2) a load-bearing casing frame structure assembly composed of casing outer ring and support plate leaf section, non-blade part and casing inner ring welded together. The full-ring channel plate is fixed radially and circumferentially by bolts, and is axially fixed on the non-blade part of the blade of the casing support plate by axial screws. The rectifying cascade assembly is radially fixed by radial screws and circumferentially and axially fixed by special radial bolts on the load-bearing casing assembly. An airflow channel is formed among the full-ring channel plate, the upper edge plate of the blade, the airfoil portion of the rectifying blade, and the airfoil portion of the blade of the support plate.

3. Advantages and effects: The beneficial effects of the present invention are: the number of turbine parts is greatly reduced, the structure can meet the requirements of support plate bearing force and blade rectification at the same time, greatly reduce the weight of turbine components, and help reduce the axial length.

Description of drawings

Figure 1 is a schematic diagram of the overall structure of the integration;

Figure 2 is an overall schematic diagram of the rectifying cascade assembly;

Fig. 3 is a schematic diagram of flow channel plate components;

Figure 4 is a schematic diagram of the connection and positioning of the rectifying cascade;

Figure 5 is a schematic diagram of the structure of the integrated part.

Detailed ways

The present invention provides an integrated structure of the turbine rear bearing casing and the rectifying blade cascade. The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

As shown in Figure 1, the structure of the load-bearing outer ring and the load-bearing inner ring of the original turbine rear load-bearing casing is retained. The invention is a structural form in which the turbine rear bearing casing and rectifying vane cascade structure are designed as one. The whole structure is divided into two components: 1) The rectifying blade airfoil part with the upper edge plate of the blade is welded to the non-blade part of the rectifying cascade with the lower edge plate of the blade through the whole ring flow channel plate to form the rectifying cascade structure assembly ; 2) A load-bearing casing frame structure assembly composed of casing outer ring and support plate blade portion, non-blade portion and casing inner ring welded together.

As shown in Figure 2, this is the rectifying cascade structure assembly, which consists of the rectifying cascade blade blade part (1), the rectifying cascade non-blade part (2), the upper edge plate (3) and the lower edge plate (4) composition. The airfoil portion of the rectifying cascade blade is also welded together with the upper edge plate of the blade, and the non-blade portion of the rectifying cascade blade is welded together with the lower edge plate of the blade.

As shown in Figure 3, since the flow channel plate is relatively thin, if the rectifier cascade blades are welded to the flow channel plate, the flow channel plate will be greatly deformed, thereby destroying the shape of the flow channel. Therefore, holes are opened on the flow channel plate, so that the airfoil portion of the rectifying cascade blade passes through the flow channel plate and the non-blade portion of the rectifying cascade blade is welded together, so that the deformation of the flow channel plate can be avoided. The front baffle and the non-blade part of the support plate attached to the full-ring runner plate are axially fixed with axial screws.

As shown in Figure 4, screw holes are opened on the outer ring of the casing (1), the upper edge plate of the rectifying cascade blades (2) and the rectifying cascade blades (3), and they are radially fixed by radial screws (4). The lower edge plate (5) of the cascade blade and the inner ring (6) of the load-bearing casing are fixed by special radial bolts (7), which are used for axial and circumferential fixation.

As shown in Figure 5, the bearing casing assembly is composed of the outer ring of the bearing casing, the inner ring of the bearing casing, the airfoil part of the support plate blade and the non-blade part of the support plate blade, wherein the airfoil part of the support plate blade It is welded together with the non-blade part of the support plate blade, and then welded together with the inner and outer rings of the load-bearing casing to form the load-bearing casing structural assembly.

In the strength calculation of the rear bearing casing, the strength and deformation of the rear bearing casing under the high temperature gas heat load behind the turbine are mainly calculated. The original calculation of the strength of the rear load-bearing casing shows that because the temperature at the load-bearing support plate is significantly higher than that of the inner and outer rings, the thermal deformation caused by the difference in thermal expansion is the main cause of stress. In this structure, the cantilever design is adopted for the rectifying cascade, which can minimize the thermal deformation incongruity caused by the fact that the thermal expansion coefficient of the cascade material is different from that of the rear bearing casing material at the same temperature , so that the stress will not increase further. The strength calculation shows that with this integrated connection and positioning method, the maximum radial stress of the integrated structure is reduced compared to the rear bearing casing.

In the calculation of the support stiffness of the rear load-bearing casing, the integrated structure of the present invention is adopted, since only the outer ring of the load-bearing casing and the upper edge plate of the blade are radially fixed, while the inner ring of the load-bearing casing The axial and circumferential displacements are only limited at the lower edge plate of the blade, so after adding the rectifying cascade, the supporting radial stiffness of the overall structure is basically unchanged.

The structure has the following advantages: (1) the flow channel plate is made into a full ring form, reducing the number of parts; (2) the airfoil part and the non-blade part of the rectifying cascade blade are welded together instead of being welded to the flow channel plate Together, the deformation of the runner plate can be avoided; (3) The runner plate is fixed on the non-blade part of the support plate blade, and the fixing method is simple and reliable; (3) Adding the rectifying cascade structure does not require a large modification of the original rear bearing case structure (4) reduce the weight of turbine components, shorten the axial length of the turbine rotor, improve the thrust-to-weight ratio, and improve the performance of the whole aero-engine.

Claims (2)

1. support case and rectification leaf grating integral structure after a turbine, after its turbine, support case portion profile is roughly the same with support case after conventional turbine, is namely made up of support case outer shroud (2), support case inner ring (9) and load support plate.It is characterized in that: its rear load support plate is band blade profile, and identical with the blade profile of rectification leaf grating, support plate blade is divided into blade profile part (11) and non-blade profile part (12); Straightener(stator) blade structure and domain flow passage plate structure (5) is with the addition of, with the connection set be used for and support plate non-leaf structure circumference is fixing on domain runner plate between load support plate.Wherein, straightener(stator) blade structure comprises: be with the blade supramarginal plate (3) of flange, rectification Cascade Blade Profile part (4), blade inframarginal (6) and the non-blade profile part (10) of rectification leaf grating; Blade supramarginal plate (3) is fixed on support case outer shroud (2) by flange and radial screw (1); Rectification Cascade Blade Profile part (4) and rectification leaf grating non-blade profile part (10) welded together through the hole on domain runner plate; Domain runner plate is fixed on the non-blade profile part (12) of load support plate by bolt (13) and screw (14); Blade inframarginal (6) rear end to be positioned after support case inner ring on end boss (8) by special radial bolts (7) axial and circumferential; Domain runner plate (5), blade (4), between blade supramarginal plate (3) and load support plate blade profile part (11), form air-flow path.

2. support case and rectification leaf grating integral structure after a kind of turbine according to claim 1, is characterized in that: between rear support case support plate, add rectification cascade structure, by support case after turbine and the integration of rectification leaf grating; The part be in by support plate in runner makes leaf structure; Runner plate is made domain form; Runner plate is fixed in the non-blade profile part of load support plate by bolt and screw; That support plate or straightener(stator) blade are all designed to blade profile part and non-blade profile part two-part; Blade supramarginal plate (3) is fixed on support case outer shroud (2) by flange and radial screw (1) by cascade structure; By special radial bolts (7) blade inframarginal (6) part direction is positioned the integrated linkage structure form of end boss (8) after support case inner ring; Special radial bolt (7) only positions the structural type of axial and circumferential.