An exhaust diffuser with adjustable cross-sectional area

Abstract

The present invention relates to an exhaust diffuser with adjustable cross-sectional area, which comprises a diffuser body and an adjustable device inserted into the throat position of the diffuser body. The adjustable device further includes: at least two porous plate assemblies, at least two guide frame assemblies, at least two guide rail assemblies, a hydraulic cylinder assembly and two support plates; under the hydraulic power action of the hydraulic cylinder assembly, the guide frames slide axially on their respective corresponding guide rails, driving the porous plates connected to the guide frames to move, and adjusting the cross-sectional area within the throat position of the diffuser body by adjusting the distance between two corresponding porous plates. The exhaust diffuser of the present invention realizes flexible adjustment of the cross-sectional area of the exhaust diffuser by arranging an adjustable device at the throat position of the diffuser body, and has the characteristics of reasonable structural design, strong flexibility, convenient operation and wide application range. The exhaust diffuser of the present invention is mainly applied to the high-altitude simulation test of aeroengines.

Description

Technical Field

[0001] The present invention belongs to the technical field of aeroengines, and particularly relates to an exhaust diffuser with an adjustable cross-sectional area. Background Art

[0002] The exhaust diffuser is one of the key pneumatic components in high-altitude simulation test equipment. Its function is to convert part of the kinetic energy of the gas discharged from the engine into pressure energy. The working principle of the exhaust diffuser is that the supersonic airflow discharged from the engine tail nozzle flows into the exhaust diffuser. Through various shock wave systems in the pipe, the pressure is increased and the speed is reduced. Then it enters the cone section of the exhaust diffuser for further pressure increase, and finally the kinetic energy of the high-temperature and high-speed airflow discharged from the engine is converted into the pressure energy of the airflow. When the pumping capacity meets the requirements, the success of the design of the exhaust diffuser is directly related to the flight altitude to be simulated in the high-altitude test and the realization of the test chamber pressure.

[0003] Currently, in the high-altitude simulation test of engines, basically each model or series of engines requires an exhaust diffuser with a fixed size. For a fixed-size exhaust diffuser, at a certain flow ratio, its critical expansion ratio is certain. When the expansion ratio exceeds this value, the diffuser is in a critical working state. In this case, the working efficiency of the exhaust diffuser is very low, and the high-altitude simulation test equipment is huge, which increases the test cost. Therefore, based on the above problems, it is of great significance to improve the structure of the exhaust diffuser for improving the aerodynamic performance and reducing the test cost.

[0004] In order to solve the technical problems existing in the existing exhaust diffuser, such as the non-adjustable cross-sectional area, insufficient expansion ratio, and inability to meet the requirements of different test conditions, the present invention provides an exhaust diffuser with an adjustable cross-sectional area, which is mainly applied to the high-altitude simulation test of aeroengines. Summary of the Invention

[0005] In view of the deficiencies in the related art, the present invention provides an exhaust diffuser with an adjustable cross-sectional area that can be applied to the high-altitude simulation test of aeroengines. By setting an adjustable device at the throat position of the diffuser body, the flexible adjustment of the cross-sectional area of the exhaust diffuser is realized. It has the characteristics of reasonable structural design, strong flexibility, convenient operation, wide application range, etc. According to the differences in the exhaust gas flow rate of the upstream engine and the altitude in the simulation test, the pressure in the test chamber can be adjusted by changing the cross-sectional area of the exhaust diffuser, so as to better adapt to different test conditions and expand the stable working range.

[0006] The present invention provides an exhaust diffuser with an adjustable cross-sectional area, comprising:

[0007] A diffuser body, with two corresponding vertical grooves provided at the throat position of the diffuser body, and a horizontal sliding groove provided at the inner bottom of the throat position of the diffuser body;

[0008] At least two porous plate assemblies, each porous plate assembly includes two vertical porous plates, the two porous plates are respectively inserted into the diffuser body through the two corresponding vertical grooves, the bottom of each porous plate is in sliding fit with the sliding groove, and the porous plate can move relatively along the sliding groove;

[0009] At least two guide frame assemblies, the guide frame assemblies are integrally arranged outside the diffuser body, each guide frame assembly includes two guide frames respectively arranged on the outer sides of the two porous plates and guide sliders installed at the bottom of each guide frame, the sides of the two guide frames are respectively fixedly connected to the side surfaces of the two porous plates, and a hydraulic cylinder assembly is connected to the other side of each guide frame;

[0010] At least two guide rail assemblies, the guide rail assemblies are integrally arranged at the bottom of the guide frame assemblies, each guide rail assembly includes two guide rails respectively arranged below the two guide frames, each guide frame is in sliding fit with the guide rail through the guide slider at its bottom, and each guide frame can slide axially along its corresponding guide rail;

[0011] Two support plates, the two support plates are respectively arranged outside the hydraulic cylinder assemblies connected to the two guide frames and are fixedly connected to their respective corresponding hydraulic cylinder assemblies;

[0012] Wherein, under the hydraulic power of the hydraulic cylinder assembly, the guide frame slides axially on its corresponding guide rail, driving the porous plate connected to the guide frame to move, and adjusting the cross-sectional area inside the throat position of the diffuser body by adjusting the distance between the two corresponding porous plates.

[0013] In some embodiments, a plurality of support frames are arranged at different positions below the diffuser body for supporting the diffuser body. The cross-section of the diffuser body is quadrilateral or circular, the shape of the porous plate is correspondingly set as quadrilateral or circular, and the size when the two porous plates in each porous plate assembly are completely closed is the same as the cross-sectional size inside the throat position of the diffuser body to ensure that the inside of the throat position of the diffuser body is in a completely closed state; the adjustable device composed of the porous plate assembly, the guide frame assembly, the guide rail assembly, the hydraulic cylinder assembly and the support plate is assembled to the throat position of the diffuser body.

[0014] In some embodiments, evenly distributed through holes are opened on each porous plate, and the through holes on the adjacent front and rear porous plates are concentric to ensure the gas flowability.

[0015] In some of these embodiments, the guiding frame is a quadrilateral structure formed by welding multiple steel plates, and reinforcing plates are also welded around the quadrilateral structure. The quadrilateral structure includes a left vertical bar portion, a right vertical bar portion, an upper horizontal bar portion, and a lower horizontal bar portion. The heights of the left vertical bar portion and the right vertical bar portion are consistent with the height of the perforated plate, and the left vertical bar portion or the right vertical bar portion is fixedly connected to the side surface of the perforated plate.

[0016] In some of these embodiments, two guiding sliders are arranged on the lower horizontal bar portion of the guiding frame, and the two guiding sliders are arranged front and back.

[0017] In some of these embodiments, the hydraulic cylinder assembly includes two hydraulic cylinders hinged to the left vertical bar portion or the right vertical bar portion of the same guiding frame. The two hydraulic cylinders are arranged up and down, and the left vertical bar portion or the right vertical bar portion of each guiding frame is connected to the piston rod end of the hydraulic cylinder by means of hinge.

[0018] In some of these embodiments, the support plate is fixedly connected to the hydraulic cylinder away from the piston rod end to ensure the stability of the movement of the perforated plate.

[0019] In some of these embodiments, at least two perforated plate assemblies are provided. The number of guiding frame assemblies and rail assemblies is consistent with the number of perforated plate assemblies, and the number of hydraulic cylinder assemblies is twice the number of perforated plate assemblies.

[0020] In some of these embodiments, the two hydraulic cylinder assemblies connected to each perforated plate assembly move in unison to ensure the smooth closing of the two perforated plates within the same perforated plate assembly. The movement of the hydraulic cylinder assemblies between different perforated plate assemblies can be controlled independently, and the perforated plates that need to be closed can be arbitrarily selected to adjust the cross-sectional area of the exhaust diffuser.

[0021] In some of these embodiments, the exhaust diffuser with adjustable cross-sectional area is applied to the high-altitude simulation test of an aeroengine.

[0022] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows:

[0023] 1. For the exhaust diffuser with adjustable cross-sectional area proposed by the present invention, by arranging an adjustable device at the throat position of the diffuser body (that is, an adjustable device composed of a perforated plate assembly, a guiding frame assembly, a rail assembly, a hydraulic cylinder assembly, and a support plate is assembled to the throat position of the diffuser body), the flexible adjustment of the cross-sectional area of the exhaust diffuser is finally realized, solving the technical problems of the existing exhaust diffuser, such as non-adjustable cross-sectional area, insufficient expansion ratio, and inability to meet the requirements of different test conditions.

[0024] 2. The exhaust diffuser with adjustable cross-sectional area proposed by the present invention can adjust the pressure in the test chamber by changing the cross-sectional area of the exhaust diffuser according to the different exhaust gas flow rates and altitudes of the upstream engine in the simulation test, so as to better adapt to different test conditions and expand the stable working range.

[0025] 3. The exhaust diffuser with adjustable cross-sectional area proposed by the present invention has the characteristics of reasonable structural design, strong flexibility, convenient operation, wide application range, etc., and can be applied to the high-altitude simulation test of aero-engines. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings described herein are used to provide a further understanding of the present invention, and constitute a part of this application. The schematic embodiments of the present invention and their descriptions are used to explain the present invention, and do not constitute an improper limitation to the present invention. In the drawings:

[0027] Figure 1 It is a schematic diagram of the overall structure (three-dimensional view) of an embodiment of the exhaust diffuser with adjustable cross-sectional area of the present invention;

[0028] Figure 2 It is a schematic diagram of the overall structure (top view) of an embodiment of the exhaust diffuser with adjustable cross-sectional area of the present invention;

[0029] Figure 3 It is a schematic diagram of the overall structure (excluding the diffuser body) of an embodiment of the exhaust diffuser with adjustable cross-sectional area of the present invention when it is completely closed;

[0030] Figure 4 It is a schematic diagram of the overall structure (excluding the diffuser body) of an embodiment of the exhaust diffuser with adjustable cross-sectional area of the present invention when it is not completely closed;

[0031] Figure 5 It is a schematic diagram of the overall structure (excluding the diffuser body) of an embodiment of the exhaust diffuser with adjustable cross-sectional area of the present invention when it is not completely closed;

[0032] Figure 6 It is a top view (excluding the diffuser body) of an embodiment of the exhaust diffuser with adjustable cross-sectional area of the present invention when it is not completely closed;

[0033] Figure 7 It is a schematic installation diagram I of an embodiment of the exhaust diffuser with adjustable cross-sectional area of the present invention;

[0034] Figure 8 It is a schematic installation diagram II of an embodiment of the exhaust diffuser with adjustable cross-sectional area of the present invention;

[0035] Figure 9 It is a schematic diagram of the structure of the guide frame in an embodiment of the exhaust diffuser with adjustable cross-sectional area of the present invention;

[0036] Figure 10 Schematic diagram of the structure of the circular perforated plate in one embodiment of the exhaust diffuser with adjustable cross-sectional area according to the present invention;

[0037] Figure 11 Schematic diagram of the structure of the circular perforated plate in different closed states in one embodiment of the exhaust diffuser with adjustable cross-sectional area according to the present invention;

[0038] Figure 12 Schematic diagram of the structure of the circular perforated plate with different through-hole diameters in one embodiment of the exhaust diffuser with adjustable cross-sectional area according to the present invention.

[0039] In the above figures:

[0040] 1. Diffuser body; 2. Perforated plate; 3. Guide frame; 4. Guide slider; 5. Guide rail; 6. Hydraulic cylinder; 7. Piston rod; 8. Support plate; 9. Test chamber; 10. Adjustable device; 11. Air extractor; 12. Aeroengine; 13. Support frame;

[0041] 21. Through hole;

[0042] 31. Left vertical strip portion; 32. Right vertical strip portion; 33. Upper horizontal strip portion; 34. Lower horizontal strip portion. Detailed implementation manners

[0043] Next, the technical solutions in the embodiments will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0044] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "transverse", "longitudinal", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and 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 therefore should not be construed as limiting the present invention.

[0045] The terms "first", "second", and "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first", "second", and "third" may explicitly or implicitly include one or more of such features.

[0046] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0047] As shown in the attached Figure 1 figure, in a schematic embodiment of an exhaust diffuser with adjustable cross-sectional area according to the present invention, the exhaust diffuser with adjustable cross-sectional area mainly includes a diffuser body 1 and an insertable adjustable device 10 disposed at the throat position of the diffuser body 1. The following will expand on these two main parts:

[0048] The attached Figure 1 figure shows the overall structural schematic diagram of an exhaust diffuser with adjustable cross-sectional area according to the present invention. The component at the center of the figure is the diffuser body 1. In order to ensure that the adjustable device 10 can be smoothly inserted into the throat position of the diffuser body 1, thereby realizing the closing and opening of the cross-section at the throat position, two corresponding vertical grooves (not shown in the figure) are provided at the throat position of the diffuser body 1 for inserting the perforated plate 2, and a horizontal sliding groove (not shown in the figure) is provided at the inner bottom of the throat position of the diffuser body.

[0049] The insertable adjustable device 10 further includes several major components such as a perforated plate assembly, a guide frame assembly, a guide rail assembly, a hydraulic cylinder assembly, and a support plate 8. Specifically, at least two perforated plate assemblies are provided in the adjustable device 10. Each perforated plate assembly includes two vertically arranged perforated plates 2. The two perforated plates 3 are respectively inserted into the interior of the diffuser body 1 through the two vertical grooves on the diffuser body 1 correspondingly. The bottom of each perforated plate 2 is in sliding fit with the horizontal sliding groove inside the diffuser body 1, enabling the perforated plate 2 to move relatively along the sliding groove. In addition, considering that the cross-sectional shape of the diffuser body 1 is mostly circular, quadrilateral, or other various shapes, the shape of the perforated plate 2 in the present invention can also be flexibly set according to the cross-sectional shape of the diffuser body 1, and the size when the two perforated plates in each perforated plate assembly are completely closed is the same as the cross-sectional size inside the throat position of the diffuser body to ensure that the inside of the throat position of the diffuser body is in a completely closed state. For example, the shape of the perforated plate 2 in the present invention can be adaptively set to be circular or quadrilateral, and its structural schematic diagram is as shown in the attached Figures 10 - 12As shown, and it can be seen from the drawings that each porous plate 2 is provided with uniformly distributed through holes, and the through holes on the adjacent porous plates 2 before and after are concentric to ensure the fluidity of the gas. If they are not concentric, the fluidity of the gas will be affected. In addition, the material of the porous plate 2 is the same as that of the exhaust diffuser, generally S31608 stainless steel. At different positions below the diffuser body 1, a plurality of support frames 13 are also provided to support the diffuser body 1.

[0050] In the adjustable device, at least two guide frame assemblies are provided. The guide frame assemblies are integrally arranged outside the diffuser body 1 (i.e., outside the throat position). Each guide frame assembly specifically includes two guide frames 3 respectively arranged on the outer sides of the two porous plates 2 and guide sliders 4 installed at the bottom of each guide frame 3. The side edges of the two guide frames 3 are fixedly connected to the side surfaces of the two porous plates 2 respectively. On the other side edge of each guide frame 3, a hydraulic cylinder assembly is also connected. Among them, regarding the specific structure of the guide frame 3, the present invention attaches Figure 9 provides a structural schematic diagram of the guide frame. It can be seen from the figure that the guide frame 3 is a quadrilateral structure welded by multiple steel plates. In order to strengthen the stability of the overall structure, reinforcing plates (not shown in the figure) can also be welded around the quadrilateral structure. The quadrilateral structure specifically includes a left vertical strip portion 31, a right vertical strip portion 32, an upper horizontal strip portion 33, and a lower horizontal strip portion 34. When designing the structure, in order to ensure the stability of the connection between the guide frame 3 and the porous plate 2, and thus improve the structural stability of the entire exhaust diffuser, it is required that the heights of the left vertical strip portion 31 and the right vertical strip portion 31 in the guide frame 3 should be the same as the height of the porous plate 2. The left vertical strip portion 31 or the right vertical strip portion 32 is fixedly connected to the side surface of the porous plate 2. On the lower horizontal strip portion 34 of the guide frame 3, two guide sliders 4 arranged front and back are also provided.

[0051] Next, in combination with the attached Figure 3 As can be seen, on the other side (i.e., the left vertical strip portion 31 or the right vertical strip portion 32) of each guide frame 3, a hydraulic cylinder assembly is connected. Each hydraulic cylinder assembly includes two hydraulic cylinders 6 hinged to the left vertical strip portion 31 or the right vertical strip portion 32 of the same guide frame 3. These two hydraulic cylinders 6 are arranged up and down, which can better drive the movement of the guide frame 3 and is more conducive to improving the flexibility and operability of the entire device. The left vertical strip portion or the right vertical strip portion of each guide frame 3 is specifically connected to the piston rod 7 end of the hydraulic cylinder 6 by a hinged manner.

[0052] At least two guide rail assemblies and two support plates 8 are provided in the adjustable device. Among them, the guide rail assemblies are integrally arranged at the bottom of the guide frame assembly. Each guide rail assembly includes two guide rails 5 respectively arranged below the two guide frames. Each guide frame 3 is slidably matched with the guide rail 5 through the guide slider 4 at its bottom, so that each guide frame 3 can slide axially along its corresponding guide rail 5. The two support plates 8 are respectively arranged outside the hydraulic cylinder assemblies connected to the two guide frames and are fixedly connected to their respective corresponding hydraulic cylinder assemblies. Moreover, the support plate 8 is fixedly connected to the hydraulic cylinder 6 away from the piston rod end. The purpose of setting the support plate is to ensure the stability of the movement of the perforated plate 2.

[0053] It should also be supplemented that in an exhaust diffuser with adjustable cross-sectional area according to the present invention, at least two perforated plate assemblies are provided. The number of guide frame assemblies and guide rail assemblies needs to be consistent with the number of perforated plate assemblies. Two support plates are provided in total, and the number of hydraulic cylinder assemblies is twice the number of perforated plate assemblies. When facing different test scenarios or working conditions, the number of perforated plates 2 is related to the aperture size of the through holes 21 on the perforated plates 2. If the aperture of the through holes 21 on each perforated plate 2 remains unchanged, then setting four perforated plate assemblies as shown in the appendix Figure 4 can meet the environmental simulation requirements at a flight altitude of 10 km and a flight speed of 1 Ma (the form of four perforated plate assemblies as shown in the appendix Figure 4 can meet the requirements of the vast majority of working conditions). Setting six perforated plate assemblies can meet the environmental simulation requirements at a flight altitude of 15 km and a flight speed of 1.5 Ma. For example, the appendix Figures 4 - 6 provides a schematic diagram of the closing conditions of the perforated plate 2 under different working conditions. Those skilled in the art need to calculate in advance the actual required number of perforated plates 2, the aperture size of the through holes 21 on the perforated plates 2, and the pre-design of other components, etc., considering various factors according to the actual needs when facing different working conditions. After obtaining a complete preset plan, the installation process of the adjustable device can be carried out. It should also be supplemented that in the exhaust diffuser with adjustable cross-sectional area according to the present invention, the two hydraulic cylinder assemblies connected to each perforated plate assembly move in unison to ensure that the two perforated plates 2 within the same perforated plate assembly can be smoothly closed. The movement of the hydraulic cylinder assemblies between different perforated plate assemblies can be controlled separately. This design method can arbitrarily select the perforated plates 2 that need to be closed to flexibly adjust the cross-sectional area of the exhaust diffuser.

[0054] Based on the above, according to different test scenario requirements or different working condition requirements, the number of perforated plate assemblies and the aperture of the through holes 21 on the perforated plate 2, etc. are pre-designed to obtain the final adjustable device 10. Then, the adjustable device 10 is installed at the throat position of the diffuser body 1. Under the hydraulic power provided by the hydraulic cylinder assembly, the guide frames 3 are driven to slide axially on their respective corresponding guide rails 5, thereby driving the perforated plate 2 connected to the guide frames 3 to move. By adjusting the distance between two corresponding perforated plates 2, the perforated plate 2 is closed according to the pre-designed scheme, and finally the purpose of adjusting the cross-sectional area inside the throat position of the diffuser body is achieved. The exhaust diffuser with adjustable cross-sectional area of the present invention can be applied to the high-altitude simulation test of aero-engines.

[0055] In addition, in combination with the attached Figure 8 An explanation is given for the reason why the adjustable device of the present invention is arranged at the throat position of the diffuser body 1: As can be seen from the attached Figure 8 figure, this figure is a schematic diagram of installing the exhaust diffuser of the present invention on the tail nozzle of an aero-engine. In the figure, A is the collection section of the diffuser, which is mainly used for ejecting air flow. The specific installation position can be moved back and forth according to the size of the aero-engine to adjust the best ejection effect. If the adjustable device is installed in this position, then the adjustable device also has to move accordingly, which is difficult to ensure airtightness, and the collection section is located inside the test chamber, and the space of the test chamber is narrow and the adjustment device cannot be installed; B is the square-to-round section of the diffuser. The overall length of this square-to-round section is short, and it belongs to a structural change connection section, which is not suitable for installation; C is the expansion section of the diffuser. The cross-sectional area of this expansion section gradually increases to reduce the air flow velocity. Adding an adjustable device on the gradually changing cross-section will make the size of the adjustable device larger and larger, and the cost is higher; D is the throat of the diffuser. The throat position belongs to the stable cross-sectional area section of the diffuser, and the cross-sectional area at the throat position is smaller than that of other positions. In this way, the size of the adjustable device can be reduced, which is convenient for installation. At the same time, considering that the air flow temperature discharged from the aero-engine is relatively high, and there is a spray device in the exhaust diffuser to discharge after cooling, so considering the structural strength, the adjustable device should also be placed as far back as possible.

[0056] Through the description of multiple embodiments of an exhaust diffuser with adjustable cross-sectional area of the present invention, it can be seen that the embodiments of the exhaust diffuser with adjustable cross-sectional area of the present invention have at least one or more of the following advantages:

[0057] 1. Strong flexibility. The exhaust diffuser with adjustable cross-sectional area proposed in the present invention realizes the flexible adjustment of the cross-sectional area of the exhaust diffuser by setting an adjustable device at the throat position of the diffuser body (that is, an adjustable device composed of a perforated plate assembly, a guide frame assembly, a guide rail assembly, a hydraulic cylinder assembly and a support plate is assembled to the throat position of the diffuser body), and solves the technical problems of the existing exhaust diffuser, such as the non-adjustable cross-sectional area, insufficient expansion ratio and inability to meet the requirements of different test conditions.

[0058] 2. Wide application range. The exhaust diffuser with adjustable cross-sectional area proposed in the present invention can adjust the pressure in the test chamber by changing the cross-sectional area of the exhaust diffuser according to the different exhaust gas flow rates and altitudes of the upstream engine in the simulation test, so as to better adapt to different test conditions and expand the stable working range.

[0059] Finally, it should be noted that the embodiments in this specification are described in a progressive manner, and the key point of each embodiment is to illustrate the differences from other embodiments. For the same or similar parts among the embodiments, reference can be made to each other.

[0060] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that: the specific implementation manners of the present invention can still be modified or some technical features can be equivalently replaced; without departing from the spirit of the technical solutions of the present invention, they should all be covered by the scope of the technical solutions claimed in the present invention.

Claims

1. An exhaust diffuser with adjustable cross-sectional area, characterized in that Comprising: A diffuser body, at the throat position of the diffuser body, there are two corresponding vertical grooves, and at the inner bottom of the throat position of the diffuser body, there is a horizontal sliding groove; At least two porous plate assemblies, each porous plate assembly includes two vertical porous plates, the two porous plates are respectively inserted into the inside of the diffuser body through the two corresponding vertical grooves, the bottom of each porous plate is in sliding fit with the sliding groove, and the porous plate can move relative to the sliding groove; At least two guide frame assemblies, the guide frame assemblies are integrally arranged outside the diffuser body, each guide frame assembly includes two guide frames respectively arranged on the outer sides of the two porous plates and guide sliders installed at the bottom of each guide frame, the sides of the two guide frames are respectively fixedly connected to the side surfaces of the two porous plates, and a hydraulic cylinder assembly is connected to the other side of each guide frame; At least two guide rail assemblies, the guide rail assemblies are integrally arranged at the bottom of the guide frame assemblies, each guide rail assembly includes two guide rails respectively arranged below the two guide frames, each guide frame is in sliding fit with the guide rail through the guide slider at its bottom, and each guide frame can slide axially along its corresponding guide rail; Two support plates, the two support plates are respectively arranged outside the hydraulic cylinder assemblies connected to the two guide frames and are fixedly connected to their respective corresponding hydraulic cylinder assemblies; Wherein, under the hydraulic power of the hydraulic cylinder assembly, the guide frame slides axially on its corresponding guide rail, driving the porous plate connected to the guide frame to move, and adjusting the cross-sectional area inside the throat position of the diffuser body by adjusting the distance between two corresponding porous plates.

2. The exhaust diffuser with adjustable cross-sectional area according to claim 1, wherein A plurality of support frames are arranged at different positions below the diffuser body for supporting the diffuser body, the cross-section of the diffuser body is quadrilateral or circular, the shape of the porous plate is correspondingly set as quadrilateral or circular, and the size when the two porous plates in each porous plate assembly are completely closed is the same as the cross-sectional size inside the throat position of the diffuser body to ensure that the inside of the throat position of the diffuser body is in a completely closed state; the adjustable device composed of the porous plate assembly, the guide frame assembly, the guide rail assembly, the hydraulic cylinder assembly and the support plate is assembled to the throat position of the diffuser body.

3. The exhaust diffuser with adjustable cross-sectional area according to claim 1, characterized in that, Uniform through holes are formed in each porous plate, and the through holes on the front and rear adjacent porous plates are concentric to ensure the gas flowability.

4. The exhaust diffuser with adjustable cross-sectional area according to claim 1, wherein The guide frame is a quadrilateral structure welded by multiple steel plates, and reinforcing plates are also welded around the quadrilateral structure. The quadrilateral structure includes a left vertical strip part, a right vertical strip part, an upper horizontal strip part and a lower horizontal strip part. The heights of the left vertical strip part and the right vertical strip part are the same as the height of the porous plate, and the left vertical strip part or the right vertical strip part is fixedly connected to the side surface of the porous plate.

5. The exhaust diffuser with adjustable cross-sectional area according to claim 4, wherein Two guide sliders are arranged on the lower horizontal strip part of the guide frame, and the two guide sliders are arranged front and back.

6. The exhaust diffuser with adjustable cross-sectional area according to claim 4, wherein The hydraulic cylinder assembly includes two hydraulic cylinders hinged to the left vertical bar portion or the right vertical bar portion of the same guide frame. The two hydraulic cylinders are arranged vertically. The left vertical bar portion or the right vertical bar portion of each guide frame is connected to the piston rod end of the hydraulic cylinder by means of hinge.

7. The exhaust diffuser with adjustable cross-sectional area according to claim 4, wherein The support plate is fixedly connected to the hydraulic cylinder away from the piston rod end to ensure the stability of the movement of the perforated plate.

8. An exhaust diffuser with adjustable cross-sectional area according to claim 6, characterized in that, At least two perforated plate assemblies are provided. The number of the guide frame assemblies and the rail assemblies is the same as that of the perforated plate assemblies. The number of the hydraulic cylinder assemblies is twice that of the perforated plate assemblies.

9. The exhaust diffuser with adjustable cross-sectional area according to claim 8, characterized in that, The two hydraulic cylinder assemblies connected to each perforated plate assembly move in unison to ensure the smooth closing of the two perforated plates within the same perforated plate assembly. The movement of the hydraulic cylinder assemblies between different perforated plate assemblies can be controlled independently, and the perforated plates to be closed can be arbitrarily selected to adjust the cross-sectional area of the exhaust diffuser.

10. An exhaust diffuser with adjustable cross-sectional area according to any one of claims 1-9, characterized in that, The exhaust diffuser with adjustable cross-sectional area is applied to the high-altitude simulation test of an aeroengine.

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