Turbofan engine and airflow guiding method for turbofan engine

Abstract

The present invention relates to a turbofan engine and an airflow guiding method for a turbofan engine. The turbofan engine includes an inner duct and an outer duct, the fan boost stage is located in the inner duct, and the inner duct includes: a fan boost stage flow path, including a boost stage casing, the boost stage casing provides a flow path space; also includes a boost stage rotor and a boost stage stator arranged alternately from upstream to downstream; a load-bearing casing flow path, including a support plate and a load-bearing casing; wherein the fan boost stage flow path and the load-bearing casing flow path are adjacently arranged upstream and downstream in the axial direction, the downstream end of the fan boost stage flow path is the boost stage rotor, the support plate has a flow guide streamline, and is adjacent to the boost stage rotor at the downstream end in the axial direction.

Description

Technical Field

[0001] The present invention belongs to the technical field of turbofan engines, and in particular relates to a turbofan engine and an airflow guiding method for the turbofan engine. Background Art

[0002] Turbofan engine, also known as turbofan engine for short, includes fan, fan boost stage, high-pressure compressor, combustion chamber and turbine. Air enters the engine from the fan. Part of the airflow sucked by the fan enters the inner duct, passes through the boost stage, high-pressure compressor and then enters the combustion chamber. In the combustion chamber, it is mixed with the fuel sprayed from the fuel nozzle and burns to form high-temperature, high-pressure combustion gas, which drives the turbine to output power. The other part of the airflow sucked by the fan is directly discharged from the outer duct.

[0003] The current turbofan engine is usually composed of five independent functional units: fan booster stage, high-pressure compressor, combustion chamber, high-pressure turbine and low-pressure turbine. A load-bearing casing structure is set between the fan booster stage and the high-pressure compressor, and between the high-pressure turbine and the low-pressure turbine to transfer the radial load of the engine and transmit it to the engine installation system through a specific force transmission path. Usually, the fan booster stage, high-pressure compressor, high-pressure turbine and low-pressure turbine are composed of rotors and stators, and the process of airflow rectification-airflow boosting or airflow work is realized through rotors and stators.

[0004] In the prior art, in order to ensure that the airflow is stable after passing through a unit body with independent functions, a stator is provided at the downstream end of the unit body, that is, at the outlet, to achieve the rectification function, which is usually called an outlet guide vane. At the same time, there is a support plate structure that transmits radial loads in the load-bearing casing structure. As mentioned above, the load-bearing casing structure is usually located at the connection of two independent functional units, that is, located at or adjacent to the outlet of a unit body, so the outlet guide vane and the support plate are usually arranged in front and behind. Summary of the invention

[0005] An object of the present invention is to provide a turbofan engine.

[0006] An object of the present invention is to provide an airflow guiding method.

[0007] A turbofan engine according to one aspect of the present invention comprises an inner duct and an outer duct, wherein the fan boost stage is located in the inner duct, and the inner duct comprises: a fan boost stage flow path, comprising a boost stage casing, wherein the boost stage casing provides a flow path space; further comprising a boost stage rotor and a boost stage stator arranged alternately from upstream to downstream; a load-bearing casing flow path, comprising a support plate and a load-bearing casing; wherein the fan boost stage flow path and the load-bearing casing flow path are adjacently arranged upstream and downstream in the axial direction, the downstream end of the fan boost stage flow path is the boost stage rotor, and the support plate has a guide streamline, which is adjacent to the boost stage rotor at the downstream end in the axial direction.

[0008] In one or more embodiments of the turbofan engine, the aerodynamic blade shape of the support plate includes a guide section front portion, a guide section tail portion, and a blade back portion, wherein the guide section front portion matches the outlet airflow vector direction of the boost stage rotor at the downstream end of the boost stage flow path, the guide section tail portion matches the airflow vector direction at the downstream high-pressure compressor inlet, and the blade back portion is arched toward the annular component of the outlet airflow vector direction of the boost stage rotor at the downstream end.

[0009] In one or more embodiments of the turbofan engine, the interior of the support plate is a hollow structure, and the hollow structure provides installation space for lubricating oil pipelines and air pipelines.

[0010] In one or more embodiments of the turbofan engine, the load-bearing casing has an upstream extension section, which is connected to the downstream end of the boost stage casing, and the downstream end of the boost stage casing surrounds the boost stage stator, which is adjacent to the boost stage rotor at the downstream end of the fan boost stage flow path, and the upstream extension section surrounds the boost stage rotor.

[0011] In one or more embodiments of the turbofan engine, the inner wall of the upstream extension section of the load-bearing casing has a wear-resistant coating.

[0012] In one or more embodiments of the turbofan engine, the upstream end of the upstream extension section has a first flange, and the downstream end of the boost stage casing has a second flange, the first flange and the second flange have corresponding matching first inner stoppers and second inner stoppers, and the upstream end of the upstream extension section and the downstream end of the boost stage casing are connected through the first flange and the second flange.

[0013] In one or more embodiments of the turbofan engine, a sealed air bleed port is further included, wherein the sealed air bleed port is located in the axial gap between the last stage booster stage rotor and the support plate.

[0014] According to an airflow guiding method for a turbofan engine according to one aspect of the present invention, the airflow is arranged to flow through the fan: a part enters the outer duct; the other part enters the inner duct, and flows out of the rotor at the downstream end of the fan boost stage of the inner duct to form an internal airflow, and the internal airflow is arranged to flow into the high-pressure compressor after being rectified by the support plate of the load-bearing casing.

[0015] In one or more embodiments of the airflow guiding method, the aerodynamic blade shape of the support plate of the load-bearing casing is configured to have a front portion of a guide section that matches the airflow vector direction of the internal airflow, a rear portion of the guide section that matches the airflow vector direction at the inlet of the high-pressure compressor, and a blade back that is arched toward the annular component of the airflow vector direction of the internal airflow.

[0016] In one or more embodiments of the airflow guiding method, the load-bearing casing is configured to have an upstream extension section, which is connected to the downstream end of the casing of the fan boost stage, and the downstream end of the casing of the fan boost stage surrounds the boost stage stator adjacent to the rotor upstream of the downstream end of the fan boost stage, and the upstream extension section is configured to surround the rotor at the downstream end of the fan boost stage.

[0017] In summary, the improved effects of the present invention include but are not limited to one or a combination of the following:

[0018] (1) The support plate of the load-bearing casing of the inner channel guides and rectifies the flow, so that the downstream end of the inner channel fan booster stage flow path does not need to be provided with a stator, thereby reducing the overall size of the core engine located in the inner channel and also reducing the overall axial size of the engine;

[0019] (2) The connection position between the load-bearing casing and the booster stage casing does not require a complex supporting and fixing structure. Only a simple connecting structure is required to connect the two, thereby reducing the structural weight and the number of parts, facilitating maintenance, and reducing manufacturing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above and other features, properties and advantages of the present invention will become more apparent through the following description in conjunction with the accompanying drawings and embodiments. It should be noted that the drawings are only examples and are not drawn to scale, and should not be used as a limitation on the actual scope of protection required by the present invention, wherein:

[0021] Figure 1 It is a schematic structural diagram of a turbofan engine according to an embodiment.

[0022] Figure 2 It is a schematic diagram of the junction of a fan boost stage flow path and a load-bearing casing flow path of a turbofan engine according to one embodiment.

[0023] Figure 3It is a schematic diagram of the junction of the fan boost stage flow path and the load-bearing casing flow path of a turbofan engine in the prior art.

[0024] Figure 4 The present invention is a schematic diagram of the connection structure between the booster stage casing and the load-bearing casing of a turbofan engine according to one embodiment.

[0025] Figure 5 The present invention is a schematic diagram of the connection structure between the booster stage casing and the load-bearing casing of a turbofan engine in the prior art.

[0026] Figure 6 It is a schematic diagram of flow guide streamlines of a support plate of a load-bearing casing flow path of a turbofan engine according to one embodiment. DETAILED DESCRIPTION

[0027] The following discloses various different implementation methods or embodiments of the subject technical solution. To simplify the disclosure, specific examples of various elements and arrangements are described below. Of course, these are only examples and are not intended to limit the scope of protection of the present invention.

[0028] In addition, it should be understood that the use of words such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above words have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that "an embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more in different locations in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures or characteristics in one or more embodiments of the present application may be appropriately combined.

[0029] like Figure 1 As shown, in one embodiment, a turbofan engine 100 includes a fan 10. After the airflow enters from the fan 10, a portion enters the outer duct 20 and a portion enters the inner duct 30. After being pressurized by the fan boost stage 1, the airflow enters the high-pressure compressor 2 for further compression to be delivered to the combustion chamber for combustion with the fuel.

[0030] The inner channel 30 includes a fan booster flow path 31 and a load-bearing casing flow path 32 located downstream of the fan booster flow path 31. The fan booster flow path 31 includes a booster casing 310, which provides a booster flow path space S1, and the booster casing 310 contains a booster rotor 311 and a booster stator 312 which are arranged alternately from upstream to downstream. Figure 1In the structure shown, the upstream end of the fan boosting stage flow path 31 is the boosting stage rotor 311, but it is not limited thereto, and the upstream end may also be the boosting stage stator 312. The bearing casing flow path 32 includes a support plate 321 and a bearing casing 320, and the bearing casing 320 provides a bearing casing flow path space S2.

[0031] refer to Figure 1 As shown, the downstream end of the fan booster flow path 31 is the booster rotor 311, combined with Figure 2 as well as Figure 3 As shown, Figure 3 Different from the prior art solution shown in the figure, the downstream end of the boost stage flow path 31' of the prior art is the boost stage stator 312', which is adjacent to the support plate 321', that is, the structure of the outlet guide vane also mentioned in the background technology. In the embodiment, the downstream end of the fan boost stage flow path 31 is the boost stage rotor 311, that is, the boost stage stator 312' (outlet guide vane) at the downstream end is cancelled, and only the support plate 321 plays a rectifying role. The support plate 321 realizes the rectifying function through the guide streamline 3210, and the gas output from the boost stage flow path 31 flows into the high-pressure compressor 2 after being rectified by the support plate 321 and is further compressed. The beneficial effect of such a setting is that the downstream end of the fan boost stage flow path 31 of the inner channel 30 does not need to be provided with a stator, and the axial space occupied by the stator is directly saved, so that the overall size of the core engine located in the inner channel is reduced, and the overall axial size of the engine is reduced.

[0032] refer to Figure 6 As shown, in some embodiments, the booster stage stator 312' (outlet guide vane) at the downstream end is removed, and the specific structure of the rectifying effect by only the support plate 321 can be that the aerodynamic blade shape of the support plate 321 has a guide section front part 322, a guide section tail part 323 and a blade back 324, such as Figure 6As shown in the schematic diagram of the guide streamline, the structural design of the support plate 321 includes matching the leading edge of the support plate 321 with the outlet airflow velocity vector at the downstream end of the supercharged stage flow path, and matching the aerodynamic blade shape of the support plate 321 according to the inlet airflow vector of the support plate 321 and the outlet airflow vector of the support plate 321 (usually the engine axis direction), that is, the front part 322 of the guide section matches the outlet airflow vector direction of the supercharged stage rotor 311 at the downstream end of the supercharged stage flow path, and the tail part 323 of the guide section matches the airflow vector direction at the inlet of the downstream high-pressure compressor 2, so that the structure of the blade back 324 is arched toward the annular component of the outlet airflow vector direction of the supercharged stage rotor 311 at the downstream end, thereby rectifying the airflow. The outlet airflow vector direction of the supercharged stage rotor 311 and the airflow vector direction at the inlet of the high-pressure compressor 2 can be obtained by aerodynamic simulation, experiment, etc. The beneficial effect of this is to simplify the structure of the support plate 321, reduce the design difficulty and processing difficulty of the support plate 321, and make its structure easy to implement.

[0033] In addition, combined Figure 1 , Figure 4 as well as Figure 6 In some embodiments, the interior of the support plate 321 may be a hollow structure, and lubricating oil pipelines, such as oil inlet and oil return pipelines for lubricating bearings, and installation space for air pipelines are provided in the hollow structure, that is, the above pipelines may pass through the hollow structure of the support plate 321. This saves installation space for pipelines in the engine, making the engine structure more compact.

[0034] In addition, combined Figure 4 as well as Figure 5 As shown, Figure 5 In the prior art shown in the figure, since the downstream end of the booster stage flow path 31' is the booster stage stator 312', the connection part between the load-bearing casing 320' and the booster stage casing 310' needs to be provided with a complex supporting and fixing structure 33' because the casing needs to support the booster stage stator 312', while the present embodiment Figure 4 As shown, only a simple connection structure is needed to connect the two, which reduces the structural weight and the number of parts, facilitates maintenance, and reduces manufacturing costs.

[0035] Continue to refer Figure 4As shown, in some embodiments, the connection transition structure between the load-bearing casing 320 and the supercharging stage casing 310 can be that the load-bearing casing 320 has an upstream extension section 3201, and the upstream extension section 3201 is connected to the downstream end 3101 of the supercharging stage casing 310, and the downstream end 3101 of the supercharging stage casing 310 surrounds the supercharging stage stator 312, and the supercharging stage stator 312 is adjacent to the supercharging stage rotor 311 at the downstream end of the fan supercharging stage flow path 31, and the upstream extension section 3201 of the load-bearing casing 320 surrounds the supercharging stage rotor 311. Such beneficial effects, combined with Figure 4 as well as Figure 5 It can be seen that Figure 5 As shown, in the prior art, a separate casing 330' is required for the last stage booster stator 312' and the adjacent booster rotor 311'. Figure 4 As shown, in the above embodiment, the casing 330' is equivalent to being an upstream extension section 3201 fused to the load-bearing casing 320, thus simplifying the casing structure and assembly process. Figure 5 The booster stage stator 312' of the prior art is shown. Figure 4 The embodiment shown in the embodiment also omits the sealing structure of the honeycomb 3121' and the comb teeth 3122' corresponding to the boost stage stator 312'.

[0036] Continue to refer Figure 4 As shown, the specific connection structure between the load-bearing casing 320 and the supercharged stage frame 310 can be that the upstream end of the upstream extension section 3201 has a first flange 3211, and the downstream end 3101 of the supercharged stage casing 310 has a second flange 3102. The first flange 3211 and the second flange 3102 have corresponding matching first inner stoppers 3103 and second inner stoppers 3212, so that the upstream end of the upstream extension section 3201 and the downstream end 3101 of the supercharged stage casing 310 are tightened and fixed by the first flange 3102, the second flange 3211 and the bolts connecting the two. The beneficial effect of this is that the structure is simple and easy to assemble, and no need is required. Figure 5 The prior art shown in the figure has a complicated supporting and fixing structure 33'. Figure 4 In some embodiments, the inner wall of the upstream extension section 3201 has a wear-resistant coating 3204, which can prevent the upstream extension section 3201 from colliding and rubbing with the boost stage rotor 311 it contains, thereby affecting the service life of the load-bearing casing 320.

[0037] In some embodiments, Figure 4 As shown, the boost stage flow path 31 may also include a bearing cavity sealing air inlet 313. The air inlet 313 is located between the boost stage rotor 311 and the support plate 321 at the downstream end of the boost stage flow path 31, and can lead air to the outside of the front bearing cavity to ensure the sealing of the front end of the front bearing cavity.

[0038] Based on the above, the airflow guiding method for a turbofan engine may be that after the airflow is set to flow through the fan 1:

[0039] A part of it enters the outer duct 20;

[0040] The other part enters the inner duct 30 and flows out of the rotor 312 at the downstream end of the fan boost stage 31 of the inner duct 30 to form an internal airflow 300, which is arranged to flow into the high-pressure compressor 2 after being rectified by the support plate 321 of the load-bearing casing 320.

[0041] Furthermore, the straightening by the support plate 321 may specifically include: the aerodynamic blade shape of the support plate 321 is set to have a guide section front portion 322 matching the airflow vector direction of the internal airflow 300, a guide section tail portion 323 matching the airflow vector direction of the inlet of the high-pressure compressor 2 (such as the inlet guide vane), and a blade back 324 arched toward the annular component of the airflow vector direction of the internal airflow 300, so as to achieve a straightening effect.

[0042] In addition, as mentioned above, Figure 4 As shown, in some embodiments, the load-bearing casing 320 is configured to have an upstream extension section 3201, and the upstream extension section 3201 is connected to the downstream end 3101 of the boost stage casing 310. The downstream end 3101 of the boost stage casing 310 surrounds the boost stage stator 312 adjacent upstream of the rotor 311 located at the downstream end of the fan boost stage. The upstream extension section 3201 is configured to surround the rotor 311 at the downstream end of the fan boost stage, which can simplify the casing structure and assembly process.

[0043] In summary, the beneficial effects of the turbofan engine and the airflow guiding method of the above embodiments include at least:

[0044] (1) The support plate of the load-bearing casing of the inner channel guides the aerodynamics, so that the downstream end of the inner channel fan booster stage flow path does not need to be provided with a stator, thereby reducing the overall size of the core engine located in the inner channel and also reducing the overall axial size of the engine;

[0045] (2) The connection position between the load-bearing casing and the booster-stage casing does not require a complex supporting and fixing structure. Only a simple connecting structure is required to connect the two, thereby reducing the structural weight and the number of parts, thereby lowering the manufacturing cost.

[0046] Although the present invention is disclosed as above with the above embodiments, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, any modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope defined by the claims of the present invention.

Claims

1. A turbofan engine, comprising an inner duct and an outer duct, It is characterized in that The fan boost stage is located in the inner channel, and the inner channel includes: The fan booster stage flow path includes a booster stage casing, which provides a flow path space; and also includes a booster stage rotor and a booster stage stator which are arranged alternately from upstream to downstream; A load-bearing casing flow path, including a support plate and a load-bearing casing; The fan booster flow path and the bearing casing flow path are adjacently arranged upstream and downstream in the axial direction, the downstream end of the fan booster flow path is the booster rotor, and the support plate has a flow guide streamline, which is adjacent to the booster rotor at the downstream end in the axial direction; The load-bearing casing has an upstream extension section, which is connected to the downstream end of the boost stage casing. The downstream end of the boost stage casing surrounds the boost stage stator, and the boost stage stator is adjacent to the boost stage rotor at the downstream end of the fan boost stage flow path. The upstream extension section surrounds the boost stage rotor.

2. The turbofan engine according to claim 1, It is characterized in that The aerodynamic blade shape of the support plate includes a guide section front portion, a guide section tail portion and a blade back portion, wherein the guide section front portion matches the outlet airflow vector direction of the boost stage rotor at the downstream end of the boost stage flow path, the guide section tail portion matches the airflow vector direction at the downstream high-pressure compressor inlet, and the blade back portion is arched toward the annular component of the outlet airflow vector direction of the boost stage rotor at the downstream end.

3. The turbofan engine according to claim 2, It is characterized in that The interior of the support plate is a hollow structure, and the hollow structure provides installation space for lubricating oil pipelines and air pipelines.

4. The turbofan engine according to claim 1, It is characterized in that The inner wall of the upstream extension section of the load-bearing casing has a wear-resistant coating.

5. The turbofan engine according to claim 1, It is characterized in that The upstream end of the upstream extension section has a first flange, and the downstream end of the supercharged stage casing has a second flange. The first flange and the second flange have corresponding matching first inner stoppers and second inner stoppers. The upstream end of the upstream extension section is connected to the downstream end of the supercharged stage casing via the first flange and the second flange.

6. The turbofan engine according to claim 1, It is characterized in that It also includes a sealed air inlet, which is located in the axial gap between the last-stage supercharging stage rotor and the support plate.

7. A method for directing airflow for a turbofan engine, It is characterized in that The airflow is set to flow through the fan: A part of it enters the outer duct; Another part enters the inner duct and flows out of the rotor at the downstream end of the fan booster stage of the inner duct to form an internal airflow, which is arranged to flow into the high-pressure compressor after being rectified by the support plate of the load-bearing casing; The load-bearing casing is configured to have an upstream extension section, which is connected to the downstream end of the casing of the fan boost stage. The downstream end of the casing of the fan boost stage surrounds the boost stage stator adjacent to the rotor upstream of the downstream end of the fan boost stage, and the upstream extension section is configured to surround the rotor at the downstream end of the fan boost stage.

8. The airflow guiding method according to claim 7, It is characterized in that The aerodynamic blade shape of the support plate of the load-bearing casing is configured to have a front portion of a guide section that matches the airflow vector direction of the internal airflow, a rear portion of the guide section that matches the airflow vector direction at the inlet of the high-pressure compressor, and a blade back that is arched toward the annular component of the airflow vector direction of the internal airflow.

Images