A flow guiding device for suppressing the internal secondary flow of an S-shaped inlet duct

Abstract

The present invention discloses a flow guiding device for suppressing the internal secondary flow of an S-shaped air intake, which relates to the technical field related to aircraft air intakes. The flow guiding device includes flow guiding vanes located in the mainstream area of the transition section of the S-shaped air intake, and the arrangement direction of the flow guiding vanes is parallel to the center line of the S-shaped air intake. The flow guiding device for suppressing the internal secondary flow of the S-shaped air intake provided by the present invention suppresses the internal secondary flow of the S-shaped air intake, thereby improving the flow field quality inside the S-shaped air intake and enhancing the performance of the engine.

Description

Technical Field

[0001] The present invention relates to the technical field related to aircraft inlets, and particularly to a flow guiding device for suppressing secondary flow inside an S-shaped inlet. Background Art

[0002] Due to its compact structure and good stealth performance, S-shaped inlets are widely used in fighter jets to provide a continuous stream of air for their engines. The main function of the inlet is to decelerate and pressurize the air flow. Therefore, the cross-sectional area of the S-shaped inlet gradually increases along the flow direction. At the same time, due to the compact structure of the S-shaped inlet, its centerline is a curve in the shape of an S. The gradually increasing cross-sectional area in the S-shaped inlet causes the longitudinal air flow to overcome the adverse pressure gradient and flow separation occurs. At the same time, the curved centerline causes secondary flow inside it. Therefore, the internal flow of the S-shaped inlet is a typical flow in a curved and expanding duct. The longitudinal flow separation and transverse secondary flow inside the S-shaped inlet will cause total pressure loss and uneven total pressure distribution of the air flow. The total pressure loss of the inlet will cause a loss of engine thrust. Some studies have shown that a one percent total pressure loss will result in a loss of about two percent of the engine thrust. The uneven total pressure distribution of the air flow across the cross-section of the inlet will affect the service life of the engine. For the above reasons, it is very necessary to adopt effective flow control means to improve the internal air flow quality of the S-shaped inlet for improving the engine performance.

[0003] In the past, people basically improved the internal flow field quality of the S-shaped inlet from the perspective of suppressing flow separation, such as vortex generators and blowing / suction control measures. There has been no flow control measure to improve the internal flow field quality of the S-shaped inlet from the perspective of suppressing secondary flow inside the inlet. Summary of the Invention

[0004] The purpose of the present invention is to provide a flow guiding device for suppressing secondary flow inside an S-shaped inlet to solve the problems existing in the above-mentioned prior art, so that the secondary flow inside the S-shaped inlet can be suppressed, thereby improving the internal flow field quality of the S-shaped inlet and enhancing the engine performance.

[0005] To achieve the above purpose, the present invention provides the following solution:

[0006] The present invention provides a flow guiding device for suppressing secondary flow inside an S-shaped inlet, including flow guiding vanes located in the mainstream area of the transition section of the S-shaped inlet. The arrangement direction of the flow guiding vanes is parallel to the centerline of the S-shaped inlet. The flow guiding vanes of the present invention are designed from the perspective of suppressing secondary flow, and improve the internal flow field quality of the S-shaped inlet and enhance the engine performance by adjusting the mainstream direction of the transition section of the S-shaped inlet to meet the requirements of turning of the curved wall surface.

[0007] Optionally, connection parts are symmetrically arranged at both ends of the flow guiding vane, and the connection parts are fixedly connected to the inner wall of the S-shaped air inlet passage.

[0008] Optionally, rectangular grooves are symmetrically formed on both sides of the flow guiding vane, and the connection parts are the side edges of the rectangular grooves.

[0009] Optionally, the number of the flow guiding vanes can be increased or decreased according to the curvature of the center line of the S-shaped air inlet passage.

[0010] Optionally, the connection parts are welded to the inner wall of the S-shaped air inlet passage.

[0011] The present invention has achieved the following technical effects compared with the prior art:

[0012] The flow in the S-shaped air inlet passage is actually a problem that the mainstream changes direction in a diffused elbow with a longitudinal adverse pressure gradient. The mainstream is affected by the adverse pressure gradient, centrifugal force and viscous force. The present invention improves the flow field quality in the S-shaped air inlet passage and suppresses the secondary flow in the S-shaped air inlet passage by introducing flow guiding vanes in the transition section of the air inlet passage to adjust the mainstream direction, and reduces the flow separation area; the flow guiding vanes are not completely connected to the inner wall of the air inlet passage, thereby avoiding the corner vortices at the connection between the flow guiding vanes and the inner wall of the S-shaped air inlet passage. Description of the Drawings

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0014] Figure 1 It is the front view of the flow guiding vane for suppressing the secondary flow inside the S-shaped air inlet passage of the present invention;

[0015] Figure 2 It is the axonometric view of the flow guiding vane for suppressing the secondary flow inside the S-shaped air inlet passage of the present invention;

[0016] In the figure, 1 is the S-shaped air inlet passage; 2 is the flow guiding vane. Detailed Embodiments

[0017] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0018] The object of the present invention is to provide a flow guiding device for suppressing the secondary flow inside an S-shaped intake duct, so as to solve the problems existing in the above-mentioned prior art, suppress the secondary flow inside the S-shaped intake duct, thereby improving the flow field quality inside the S-shaped intake duct and enhancing the performance of the engine.

[0019] In order to make the above objects, features and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0020] The present invention provides a flow guiding device for suppressing the secondary flow inside an S-shaped intake duct, as Figure 1 and Figure 2 shown, which includes two flow guiding vanes 2 located inside the S-shaped intake duct 1. In order to determine the arrangement mode and geometric dimensions of the flow guiding vanes 2, while not increasing the total pressure loss, the total pressure distortion is reduced; the arrangement direction of the flow guiding vanes 2 is parallel to the center line of the S-shaped intake duct 1. The flow guiding vanes 2 of the present invention are designed from the perspective of suppressing the secondary flow. Since the flow guiding vanes 2 are used to adjust the direction of the main flow, the two flow guiding vanes 2 are arranged in the main flow region of the transition section of the S-shaped intake duct 1. By adjusting the main flow direction of the transition section of the S-shaped intake duct 1 to meet the requirements of the curved wall turning, the flow field quality inside the S-shaped intake duct 1 is improved and the performance of the engine is enhanced.

[0021] A part of each side of the flow guiding vane 2 is respectively cut off, thus forming two rectangular grooves. After a part is cut off, both ends of the flow guiding vane 2 form four protrusions located on both sides, which serve as connecting parts. These connecting parts are welded to the wall surface of the S-shaped intake duct 1 through the contact points at their respective ends, so that the flow guiding vane 2 is not completely connected to the wall surface of the S-shaped intake duct 1, avoiding the corner vortices at the connection between the flow guiding vane 2 and the wall surface of the S-shaped intake duct 1; in order to adjust the main flow direction to a greater extent, there is a certain distance between the flow guiding vane 2 and the upper and lower wall surfaces of the S-shaped intake duct 1. The distance between the two flow guiding vanes 2 is taken as 0.4 times the cross-sectional diameter of the S-shaped intake duct 1. The number of the flow guiding vanes 2 can be increased according to the curvature of the center line of the S-shaped intake duct 1.

[0022] When the present invention works, the uniform air flow enters the inside of the S-shaped intake duct 1. The flow guiding vanes 2 located in the transition section of the S-shaped intake duct 1 adjust the main flow direction to make the air flow meet the requirements of the curved wall turning, so that the secondary flow inside the S-shaped intake duct 1 can be suppressed. At the same time, the flow separation region inside the S-shaped intake duct 1 will also be reduced. The flow guiding vanes 2 introduced into the main flow region of the transition section of the S-shaped intake duct 1 have an obvious effect on adjusting the main flow direction inside the S-shaped intake duct 1. The flow guiding vanes 2 can not only effectively suppress the non-uniformity generated by the secondary flow inside the S-shaped intake duct 1, but also play a role in controlling the flow separation on the wall surface of the S-shaped intake duct 1, thus significantly improving the air flow quality at the AIP section and the performance of the engine.

[0023] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "top", "bottom", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0024] Specific examples are used in the present invention to illustrate the principles and implementation manners of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A flow guiding device for suppressing the secondary flow inside an S-shaped intake duct, characterized in that: It includes guide vanes located in the mainstream area of the transition section of the S-shaped inlet duct. The arrangement direction of the guide vanes is parallel to the center line of the S-shaped inlet duct; connection parts are symmetrically arranged at both ends of the guide vanes, and the connection parts are fixedly connected to the inner wall of the S-shaped inlet duct; rectangular grooves are symmetrically formed on both sides of the guide vanes, and the connection parts are the side edges of the rectangular grooves.

2. The flow guiding device for suppressing the secondary flow inside the S-shaped intake duct according to claim 1, wherein: The number of the guide vanes can be increased or decreased according to the curvature of the center line of the S-shaped inlet duct.

3. The flow guiding device for suppressing the secondary flow inside the S-shaped inlet passage according to claim 1, wherein: The connection parts are welded to the inner wall of the S-shaped inlet duct.

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