An adjustable inlet total pressure-swirl coupling distortion simulation device and simulation method

Abstract

The application provides a design method of a new type of total pressure and swirl coupling distortion simulation device of an aero-engine inlet duct, which can not only simulate whole vortex or swirl flow distortion, but also simulate coupling distortion of total pressure distortion and the two kinds of swirl flow distortion, and can also be adjusted within a certain range according to the distortion size of the required AIP section in actual use. The design of the new type of adjustable swirl type total pressure and swirl coupling distortion generator mainly comprises a circular pipe, an insert plate and a plurality of swirl blades. The control of the total pressure distortion intensity can be realized by adjusting the height of the insert plate, and the type, direction and intensity of the swirl flow distortion can be realized by adjusting the installation angle of the swirl blades. The design idea of the application is simple, the design method is easy to realize, the function is complete, and the required inlet total pressure and swirl distortion flow field can be provided for the compressor inlet in the working scene of the aero-engine ground test.

Description

Technical fields:

[0001] This invention belongs to the field of aircraft air intakes and can simulate the total pressure and swirling coupling distortion on the AIP cross section of the air intake. Background technology:

[0002] With the development of aviation technology, the performance requirements for aero engines are becoming increasingly stringent, leading to more diverse intake configurations, such as S-curve intakes and recessed intakes. While these intakes improve certain engine performance aspects, the increased vortex distortion on the AIP (Air-Independent Propulsion) section after the incoming airflow passes through them directly affects the compressor's stability margin, posing new challenges to the matching of the intake and engine. For most mainstream aircraft currently in service, both overall vortex distortion and tandem vortex distortion occur in their intakes. These two types of vortex distortion are the most common and should therefore be given greater attention in intake distortion research.

[0003] To investigate the impact of distortion on inlet-engine compatibility and conduct ground engine tests, various distortion generator structures have been developed to simulate distortion on the AIP (Air Inlet Propulsion) cross-section. For simulating total pressure distortion, common methods include installing distortion screens, simulation plates, and inserts at the air supply duct inlet or inside the duct. For simulating inlet swirling distortion, methods include rotating blades, delta wing methods, swirling cavity methods, and distortion mesh methods. However, the aforementioned total pressure and swirling distortion simulators and existing distortion generators can only simulate either total pressure distortion or swirling distortion individually, or only the coupled distortion of total pressure and vortex distortion. In practical engineering, for the flow within the inlet, the total pressure distortion and... Swirl distortion often coexists. For different types of air intakes, the types of swirl distortion can be either opposite vortex swirl distortion or overall vortex swirl distortion. Moreover, the intensity of the distortion also varies depending on the incoming flow conditions. In engine wind tunnel experiments, we often need to test the working conditions under different conditions. Therefore, it is necessary to simulate the flow on the AIP section under different incoming flow conditions. Thus, a distortion simulation device is needed that can simulate coupled distortion, simulate overall vortex and opposite vortex swirl distortion, and adjust the distortion intensity. Summary of the Invention:

[0004] This invention addresses the shortcomings of existing distortion generator technologies mentioned in the background section. It can simulate not only the overall vortex or vortex-swirling distortion separately, but also the coupled distortion of total pressure distortion with these two types of swirling distortion. In experiments, the distortion intensity can be adjusted in real time according to the compressor's requirements for the total pressure-swirling distortion intensity, which is convenient for engineering implementation.

[0005] The present invention adopts the following technical solution:

[0006] An adjustable swirl-type total pressure and swirl coupling distortion generator includes a circular tube, an adjustable insert plate, and several swirl components.

[0007] The circular tube is hollow inside and equipped with a vertically movable insert plate and adjustable-angle swirl blades. The diameter of the circular tube is D. The insert plate is located at the inlet of the circular tube at a distance of one diameter. The leading edge of the swirl blades is at the same cross-section as the insert plate. The insert plate is a rectangular baffle with an adjustable insertion height and a length equal to the diameter D. At the same time, a groove is cut at a corresponding position on the pipe. The groove width matches the thickness of the baffle, and the height of the groove along the normal direction is equal to the maximum adjustable height of the baffle. The baffle moves up and down through a sliding groove under the control of a motor and does not contact the swirl blades.

[0008] As a bladed hydrocyclone, the swirl blades are arranged in a centripetal manner with the center of the circular tube cross-section as the axis, and are uniformly arranged along the inner diameter of the circular tube. A servo motor is used to achieve stepless adjustment and fixation of the swirl blades.

[0009] An AIP section is also provided at a distance of 3 times the diameter downstream of the insert channel.

[0010] Preferably, the swirl blades are 2N symmetrical fan-shaped blades, divided into two groups on the left and right sides along the central axis of the circular tube section. The installation positions are symmetrically distributed. The angle of each swirl blade is infinitely adjustable, with an adjustment range of -15° to +15°. By adjusting the swirl direction of the two groups of swirl blades, the conversion between the simulated overall vortex and the vortex can be achieved.

[0011] Preferably, the insertion height of the insert plate is adjustable from 0 to 0.25D, and the overall height is 1.1 to 1.2 times the maximum adjustable height. The total pressure distortion intensity at the AIP section is adjusted by adjusting the depth of the insert plate.

[0012] The present invention also discloses a simulation method for an adjustable inlet total pressure-swirl coupling distortion simulation device. Based on the above simulation device, total pressure distortion and swirl distortion develop and couple in the middle section of the circular tube at the front end of the insert plate and the AIP section, and finally obtain the required compressor inlet total pressure and swirl distortion coupled flow field on the AIP section.

[0013] The swirl blades are divided into two groups, left and right. The conversion between the simulated overall vortex and the vortex is achieved by adjusting the swirl direction of the two groups of swirl blades. The total pressure distortion intensity is changed by adjusting the insertion depth of the insert plate.

[0014] As a preferred option, the angles and directions of the swirling blades on both sides of the hydrocyclone are adjusted to be the same. Under the condition that the blades have the same direction of rotation, different installation angles are adopted to simulate the distortion of the biased overall vortex flow.

[0015] As a preferred option, the angles of the swirling blades on the left and right sides of the hydrocyclone are adjusted to be the same and the swirling directions are opposite. Under the condition that the blades swirl in opposite directions, different installation angles are adopted to simulate the distortion of the vortex flow caused by the offset.

[0016] Compared with existing distortion generators, the present invention has the following advantages:

[0017] 1. This invention, through the insert plate and adjustable swirl blades, can realize both separate simulation of total pressure and overall vortex, as well as simulation of vortex distortion, and coupled simulation of total pressure distortion, overall vortex, and vortex distortion.

[0018] 2. The total voltage distortion intensity can be adjusted by adjusting the height of the insert plate;

[0019] 3. Each swirl blade can be controlled individually. By adjusting the swirl angle, different intensities of swirl distortion can be obtained.

[0020] 4. The angles of the left and right sets of blades can be adjusted to simulate the distortion of offset overall vortex or offset vortex vortex. Attached image description:

[0021] Figure 1 This is a schematic diagram of the structure of the present invention;

[0022] Figure 2 Swirl distortion on AIP cross section for different blade installation angle models at different incoming Mach numbers;

[0023] Figure 3 This is a simulation device for total pressure-integrated vortex flow distortion.

[0024] Figure 4 The flow field on the AIP section is the total pressure-integral vortex distortion when the swirl blade angle is 10°.

[0025] Figure 5 A total pressure-to-vortex flow distortion simulation device;

[0026] Figure 6 The total pressure versus vortex distortion at the AIP section is the flow field when the blade angle is ±10°.

[0027] Figure label:

[0028] 1-Insert plate, 2-Swirl blade. Detailed implementation method:

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] This invention relates to an adjustable inlet total pressure-swirl coupling distortion simulation device and its design method. This distortion simulation device can simulate the distortion generated by airflow within the inlet, providing a near-realistic distortion simulation for the AIP (Air-Independent Propulsion) section in ground-based wind tunnel experiments. Figure 1 As shown, the casing is constructed as a straight circular tube, inside which is a vertically movable insert plate and adjustable-angle swirl blades 2. The diameter of the circular tube is D. The insert plate 1 is located at the inlet of the circular tube at a distance of 1 diameter, and its depth is adjustable from 0 to 0.25D. The leading edge of the swirl blades is at the same cross-section as the insert plate, and the AIP cross-section is located 3D behind the insert plate. The swirl blades are divided into left and right groups. By adjusting the swirl direction of the two groups of swirl blades, the simulation of a whole vortex and a counter-vortex can be achieved.

[0031] In this embodiment, the diameter D of the circular pipe is 0.778m. A rectangular baffle with a thickness of 10mm is inserted, its height being 1.1 to 1.2 times the maximum adjustable height, and its length being the diameter length, with a maximum adjustable height of 97.25mm. A groove is cut at a corresponding position on the pipe, the groove width slightly greater than the baffle thickness, and the height of the groove along the normal direction equal to the maximum adjustable height of the baffle. The baffle moves up and down within the groove under motor control, without contacting the swirling blades. The swirling blades, acting as blade-type swirling devices, are uniformly arranged radially along the inner diameter of the circular pipe, with the center of the circular pipe cross-section as the axis. There are 2N swirling blades, symmetrically shaped fan-shaped, divided into left and right groups along the central axis of the circular pipe cross-section, symmetrically distributed in installation positions. The angle of each swirling blade is infinitely adjustable, ranging from -15° to +15°. A servo motor is used to achieve infinitely adjustable and fixed blades. The swirling type and intensity are controlled by adjusting the angle of the swirling blades. An AIP section is also provided at a distance of 3 times the diameter downstream of the insert channel.

[0032] The incoming flow enters the distortion generator from the pressure inlet, first passing through the insert plate to generate total pressure distortion, and then passing through the subsequent bladed vortex generator to generate swirling distortion. The total pressure distortion and swirling distortion couple and develop in the subsequent circular tube. The coupled distortion on the AIP cross-section can simulate the distortion at the inlet outlet. The height of the insert plate is freely adjustable, thereby controlling the magnitude of the total pressure distortion; raising the insert plate increases the total pressure distortion. The swirling blades use the symmetrical blade design NACA0012, divided into two groups, each with five blades, symmetrically distributed. The blade installation angle can vary between 15° and -15°. Each blade is connected to a servo motor on the outside of the cylinder, controlling the rotation and fixation of each blade's angle, thus simulating the conversion from a whole vortex to a pair of vortices and adjusting the intensity of the swirling distortion. Figure 2The swirling distortion on the AIP section under different incoming Mach numbers for different blade installation angles is presented. Hollow shapes represent overall vortex distortion, while solid shapes represent paired vortex distortion. When simulating overall vortex distortion, the larger the blade installation angle, the greater the swirling distortion on the AIP section. When simulating paired vortex distortion, the two sets of blades rotate in opposite directions; the larger the installation angle, the greater the swirling distortion intensity, but the increase in swirling distortion intensity with increasing installation angle is not significant.

[0033] The structure of the total pressure-integrated vortex generator simulation device is as follows: Figure 3 As shown, the blades on both sides of the hydrocyclone rotate in the same direction at this time. To simulate the overall vortex flow distortion, adjust the blade angles on both sides to be the same; under the condition that the blade rotation direction is the same, different installation angles of the blades can simulate the biased overall vortex flow distortion. Figure 4 The flow field on the AIP section is given when the installation angle is 10°. The velocity vector diagram shows that the secondary flow on the section rotates counterclockwise, and the low total pressure zone is lifted from the bottom to the middle under the action of the swirling flow.

[0034] The structure of the total pressure-to-vortex generator simulation device is as follows: Figure 5 As shown, the blades on both sides of the hydrocyclone rotate at the same angle but in opposite directions. By using different installation angles for the blades, the distortion of the vortex flow due to offset can be simulated. Figure 6 The flow field on the AIP section is given when the installation angles of the two sets of blades are 10° and -10°. The velocity vector diagram shows that there are two symmetrical vortices at the top of the section, and the low-pressure area is reduced due to the influence of the vortices.

[0035] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An adjustable intake total pressure-swirl coupling distortion simulation device, characterized in that, The distortion simulation device has a hollow cylindrical shell, inside which there is a vertically movable insert plate and an adjustable swirl blade. The diameter of the circular tube is D. The insert plate is located at the inlet of the circular tube at a distance of 1 diameter. The leading edge of the swirl blade is at the same cross section as the insert plate. The insert plate is a rectangular baffle with an adjustable insertion height and a length equal to the diameter D. At the same time, a groove is cut at the corresponding position on the pipe. The groove width matches the thickness of the baffle. The height of the groove along the normal direction is equal to the maximum adjustable height of the baffle. The baffle moves up and down through the slide under the control of the motor and does not contact the swirl blade. The swirl blades are 2N symmetrical fan-shaped blades, symmetrically distributed in the installation position. The angle of each swirl blade is infinitely adjustable, with an adjustment range of -15° to +15°. The swirl intensity can be controlled by adjusting the angle of the swirl blades. The swirling blades, acting as a bladed hydrocyclone, are uniformly and concentrically arranged along the inner diameter of the circular tube, with the center of the tube's cross-section as the axis. The tube is divided into left and right groups along the central axis of its cross-section, and a servo motor is used to achieve stepless adjustment and fixation of the swirl blades. The conversion between the simulated overall vortex and the vortex is achieved by adjusting the swirl direction of the two sets of swirl blades; an AIP section is also provided at a distance of 3 times the diameter downstream of the insert plate channel.

2. The adjustable intake total pressure-swirl coupling distortion simulation device according to claim 1, characterized in that, The insertion height of the insert plate is adjustable from 0 to 0.25D, and the overall height is 1.1 to 1.2 times the maximum adjustable height. The total pressure distortion intensity at the AIP section can be adjusted by adjusting the depth of the insert plate.

3. A simulation method for an adjustable intake total pressure-swirl coupling distortion simulation device, characterized in that, The simulation method is based on the simulation device as described in claim 1. The total pressure distortion and swirling distortion develop and couple in the middle section of the circular tube at the front end of the insert plate and the AIP section, and finally obtain the required compressor inlet total pressure and swirling distortion coupled flow field on the AIP section. The swirling blades are divided into left and right groups, and the conversion between the simulated overall vortex and the vortex is achieved by adjusting the swirling direction of the two groups of swirling blades. The intensity of the total pressure distortion is changed by adjusting the insertion depth of the insert plate.

4. The simulation method of the adjustable intake total pressure-swirl coupling distortion simulation device according to claim 3, characterized in that, Adjust the swirling blades on both sides of the hydrocyclone to rotate in the same direction. Under the condition that the blades rotate in the same direction, adopt different installation angles to simulate the distortion of the biased overall vortex flow.

5. The simulation method of an adjustable intake total pressure-swirl coupling distortion simulation device according to claim 3 or 4, characterized in that, Adjust the swirling blades on the left and right sides of the hydrocyclone to rotate in opposite directions. Under the condition that the blades rotate in opposite directions, adopt different installation angles to simulate the distortion of the vortex flow caused by the offset.

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