A passive flow field quality regulating device for a two-dimensional cascade wind tunnel

Abstract

The application belongs to the technical field of subsonic plane cascade wind tunnel test, and particularly relates to a passive regulation device for flow field quality of a plane cascade wind tunnel, which comprises blades, a front grid plate, a rear grid plate, an upper tail plate and a lower tail plate. The front grid plate and the rear grid plate are arranged side by side in the plane cascade wind tunnel, and the blades are arranged in multiple groups and are spaced apart from each other between the front grid plate and the rear grid plate. The upper tail plate and the lower tail plate are arranged in a vertical manner and are connected with the front grid plate and the rear grid plate. The upper tail plate is provided with an upper guide wall at a position corresponding to the uppermost blade, and the lower tail plate is provided with a lower guide wall at a position corresponding to the lowermost blade. The configuration of the lower side wall surface of the upper guide wall and the upper side wall surface of the lower guide wall is designed according to the pressure surface profile of the measured blade profile. Adjusting the installation angle of the upper and lower guide walls and the upper and lower tail plates coupled therewith can effectively improve the periodicity of the plane cascade flow field of a compressor with a large attack angle and a small bending degree or a large bending degree, and has the advantages of low experimental cost, low equipment complexity and small adjustment difficulty.

Description

Technical Field

[0001] This application belongs to the field of subsonic planar cascade wind tunnel testing technology, and specifically relates to a passive control device for flow field quality in a planar cascade wind tunnel. Background Technology

[0002] Planar blade cascade wind tunnel testing technology is a fundamental testing technique in the field of axial-flow turbomachinery. With the increasing demand for high-load airfoil design in modern aero-engines, the requirements for the reliability and accuracy of planar blade cascade wind tunnel testing technology are becoming increasingly stringent. The flow field quality in the planar blade cascade wind tunnel is a core factor determining the quality of planar blade cascade testing.

[0003] The structure of a conventional planar cascade wind tunnel test section is as follows: Figure 1 As shown, the movable upper wall plate 1 and lower wall plate 6 allow the upstream airflow to flow into the test section along the wind tunnel axis. The planar blade cascade test piece 4 is mounted on a rotatable disk 3. The angle of attack of the incoming flow into the cascade is continuously adjusted by rotating the rotatable disk 3. After adjusting to a certain angle of attack, the upper wall plate 1 is moved to connect with the top blade 2 of the planar blade cascade test piece 4, and the lower wall plate 6 is moved to connect with the bottom blade 5 of the planar blade cascade test piece 4 to close the rectangular flow channel. Planar blade cascade experiments based on the conventional test section structure revealed that for compressor blade cascades with large angles of attack or large camber, channel blockage is prone to occur in the cascade channels near the top blade 2 and the bottom blade 5, and this blockage is transmitted circumferentially. Under the action of this pressure difference in the cascade pitch direction, the flow in each channel of the planar blade cascade becomes different, the uniformity before the cascade and the periodicity after the cascade decrease, and the flow field quality of the tested blade channel cannot be guaranteed, which seriously affects the quality of the planar blade cascade test data.

[0004] Some researchers have attempted to improve flow field quality by drawing boundary layer between the upper wall plate 1 and the top blade 2, and between the lower wall plate 6 and the bottom blade 5 in a planar blade cascade wind tunnel. However, studies have shown that while active control methods based on drawing layer effectively improve the uniformity of the cascade inlet, they have very limited impact on the periodicity of the cascade outlet angle. Other researchers have found that passive control methods, such as optimizing the circumferential endwall shape of the test section and adding adjustable tailplates, significantly improve the flow field quality of the planar blade cascade wind tunnel, particularly effectively improving the periodicity of the cascade outlet angle. However, due to the complexity of the passive control process, implementing passive control in the limited space of a planar blade cascade wind tunnel test section presents certain challenges. Currently, there are very few cases of applying such passive control technologies to actual planar blade cascade wind tunnels.

[0005] Therefore, ensuring the quality of the flow field in a planar blade cascade wind tunnel is a problem that needs to be solved. Summary of the Invention

[0006] To address the aforementioned issues, this application provides a passive control device for the flow field quality of a planar blade cascade wind tunnel, which addresses the problem of effectively improving the flow field quality in a planar blade cascade wind tunnel, a problem that needs to be solved.

[0007] The technical solution of this application is: a passive control device for the flow field quality of a planar blade wind tunnel, comprising blades, a front cascade plate, a rear cascade plate, an upper tail plate, and a lower tail plate;

[0008] The front and rear gratings are arranged side by side in the blade grating wind tunnel, and the blades are arranged in multiple sets, spaced vertically between the front and rear gratings;

[0009] The upper tail plate and the lower tail plate are arranged above and below each other and are both connected to the front grid plate and the rear grid plate. The upper tail plate is provided with an upper guide wall at the position corresponding to the uppermost blade, and the lower tail plate is provided with a lower guide wall at the position corresponding to the lowermost blade.

[0010] The configuration of the lower side wall of the upper guide wall and the upper side wall of the lower guide wall is designed according to the pressure surface profile of the airfoil being tested.

[0011] Preferably, the front grid plate has a first circular mounting hole and a second circular mounting hole at both ends, the rear grid plate has a third circular mounting hole and a fourth circular mounting hole at both ends, the upper guide wall has both ends threadedly connected to the first circular mounting hole and the third circular mounting hole, and the lower guide wall has both ends threadedly connected to the second circular mounting hole and the fourth circular mounting hole.

[0012] There are gaps between the first and second circular mounting holes and the upper guide wall, and between the third and fourth circular mounting holes and the lower guide wall at their threaded connections.

[0013] Preferably, the upper guide wall includes a first guide plate, a first front end nut, a first rear end nut, and a first pointer;

[0014] The lower sidewall is provided on the first guide plate, the first front nut and the first rear nut are respectively provided on both sides of the first guide plate, and the first pointer is provided on the outside of the first front nut; the first guide plate, the first front nut, the first rear nut and the pointer are connected by bolts;

[0015] The direction indicated by the first pointer is always consistent with the chord length direction of the blade, and the installation angle of the upper guide wall can be continuously adjusted by rotating the first pointer.

[0016] Preferably, the lower guide wall includes a second guide plate, a second front end nut, a second rear end nut, and a second pointer;

[0017] The lower sidewall is provided on the second guide plate, the second front nut and the second rear nut are respectively provided on both sides of the second guide plate, and the second pointer is provided on the outside of the second front nut; the second guide plate, the second front nut, the second rear nut and the pointer are connected by bolts;

[0018] The second pointer always points in the same direction as the blade chord length, and the installation angle of the lower guide wall can be continuously adjusted by rotating the second pointer.

[0019] Preferably, the upper guide wall is vertically inserted into the first circular mounting hole and the third circular mounting hole at both its front and rear ends; the lower guide wall is vertically inserted into the second circular mounting hole and the fourth circular mounting hole at both its front and rear ends.

[0020] Preferably, the upper tail plate includes a first plate body, a first supporting rib, a second supporting rib, and a first clamping bolt;

[0021] The first plate is a cuboid structure. The first support rib and the second support rib are respectively connected to the two ends of the first plate. There are two sets of the first clamping bolts, which are threaded into the first support rib and the second support rib respectively.

[0022] Preferably, the lower tail plate includes a second plate, a third supporting rib, a fourth supporting rib, and a second clamping bolt;

[0023] The second plate is a cuboid structure. The third and fourth support ribs are respectively connected to the two ends of the second plate. There are two sets of the second clamping bolts, which are threaded into the third and fourth support ribs respectively.

[0024] Preferably, the lower inlet of the upper tail plate is connected to the lower inlet of the upper guide wall, and the upper inlet of the lower tail plate is connected to the upper outlet of the lower guide wall.

[0025] Preferably, the inlets of both the upper and lower tailplates are designed at an angle.

[0026] Preferably, the number of blades is 7, and the distance between the beginning and end of the upper guide wall and the lower guide wall is set as the blade chord length; the circumferential distance between the lower wall surface of the upper guide wall and the upper wall surface of the lower guide wall and the adjacent blade is the blade cascade pitch; the rotation axis of the upper guide wall and the lower guide wall passes through their beginning points; the upper end of the upper guide wall and the lower end of the lower guide wall are non-airflow surfaces.

[0027] Preferably, the mounting angles of the upper and lower guide walls, as well as the mounting angles of the upper and lower tail plates, are defined with the blade chord length direction as the reference; the thickness of both the upper and lower tail plates is set to 10 mm; the length of both the upper and lower tail plates is set to 6 times the blade chord length; the chamfering at the leading ends of the upper and lower tail plates is sufficient to ensure that the upper and lower tail plates can rotate around the ends of the upper and lower guide walls, respectively. 20°.

[0028] Preferably, the width of the upper tail plate and the lower tail plate is processed to be less than the blade height H by 0.5 mm; the distance between the supporting ribs of the upper tail plate and the front and rear sidewalls of the test section is 1 mm.

[0029] The passive control device for wind tunnel flow field quality of the planar blade cascade wind tunnel in this application has the following advantages:

[0030] When applied to conventional planar blade cascade wind tunnel experiments, adjusting the installation angles of the upper and lower guide walls and their coupled upper and lower tail plates can effectively improve the periodicity of the compressor planar blade cascade flow field with large angle of attack and small or large camber. It has the advantages of low experimental cost, low equipment complexity, and easy adjustment. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the wind tunnel test section of a compressor planar blade cascade in the background technology.

[0032] Figure 2 This is a structural diagram of the flow field quality control device with adjustable guide wall and tail plate of this application.

[0033] Figure 3 This is a diagram showing the assembly relationship between the blades of this application and the front and rear cascade plates;

[0034] Figure 4 This diagram shows the assembly and fixing relationship of the various components of the upper guide wall with adjustable installation angle in this application.

[0035] Figure 5 This diagram shows the assembly and fixing relationship of the various components of the adjustable mounting angle lower guide wall in this application.

[0036] Figure 6 This is a diagram showing the assembly and fixing relationship of the various components of the adjustable mounting angle upper tail plate of this application;

[0037] Figure 7 This is a diagram showing the assembly and fixing relationship of the various components of the adjustable mounting angle lower tail plate of this application.

[0038] 1. Upper wall plate; 2. Top blade; 3. Rotatable disk; 4. Planar blade cascade experimental piece; 5. Bottom blade; 6. Lower wall plate; 7. Blade; 8. Front cascade plate; 8-1. First circular mounting hole; 8-2. First airfoil groove; 8-3. Second circular mounting hole; 9. Rear cascade plate; 9-1. Third circular mounting hole; 9-2. Second airfoil groove; 9-3. Fourth circular mounting hole; 10. Upper guide wall; 10-1. First pointer; 10-2. First front end nut; 10-3, Lower side wall; 10-4, First rear end nut; 11, Lower guide wall; 11-1, Second pointer; 11-2, Second front end nut; 11-3, Upper side wall; 11-4, Second rear end nut; 12, Upper tail plate; 12-1, First support rib; 12-2, Second support rib; 12-3, First clamping bolt; 13, Lower tail plate; 13-1, Third support rib; 13-2, Fourth support rib; 13-3, Second clamping bolt. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are only some, not all, of the embodiments of this application. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0040] The first aspect of this application provides a passive control device for the flow field quality of a planar blade cascade wind tunnel, such as... Figures 2-3 It includes blades 7, front grid plate 8, rear grid plate 9, upper tail plate 12, and lower tail plate 13.

[0041] The front grid plate 8 and the rear grid plate 9 are arranged side by side in the blade wind tunnel, and there are multiple sets of blades 7 arranged vertically between the front grid plate 8 and the rear grid plate 9.

[0042] The upper tail plate 12 and the lower tail plate 13 are arranged vertically and are both connected to the front grid plate 8 and the rear grid plate 9. The upper tail plate 12 is provided with an upper guide wall 10 at the position corresponding to the uppermost blade 7, and the lower tail plate 13 is provided with a lower guide wall 11 at the position corresponding to the lowermost blade 7.

[0043] The configuration of the lower side wall 10-3 of the upper guide wall 10 and the upper side wall 11-3 of the lower guide wall 11 is designed according to the pressure surface profile of the airfoil being tested.

[0044] By setting up upper and lower guide walls 11 designed according to the pressure surface profile of the tested blade, the large-angle deflection of the airflow at the circumferential endwall can be reduced, flow separation can be suppressed, and the periodicity of the blade flow field can be improved. The whole structure adopts a passive structure, which does not require active control such as suction. The structure is simple and the test cost is low.

[0045] Preferably, the front grid plate 8 has a first circular mounting hole 8-1 and a second circular mounting hole 8-3 at both ends, the rear grid plate 9 has a third circular mounting hole 9-1 and a fourth circular mounting hole 9-3 at both ends, the upper guide wall 10 is threaded to the first circular mounting hole 8-1 and the third circular mounting hole 9-1 at both ends, and the lower guide wall 11 is threaded to the second circular mounting hole 8-3 and the fourth circular mounting hole 9-3 at both ends.

[0046] There are gaps between the first circular mounting hole 8-1 and the second circular mounting hole 8-3 and the threaded connection between the upper guide wall 10, the third circular mounting hole 9-1 and the fourth circular mounting hole 9-3 and the lower guide wall 11.

[0047] A pre-reserved gap is provided between the circular mounting hole and the threaded end of the guide wall, allowing the upper and lower guide walls 11 to rotate freely and achieve continuously adjustable mounting angles; the threaded connection facilitates assembly and locking, taking into account both adjustment flexibility and installation stability.

[0048] like Figure 4 Preferably, the upper guide wall 10 includes a first guide plate, a first front end nut 10-2, a first rear end nut 10-4, and a first pointer 10-1;

[0049] The lower sidewall 10-3 is provided on the first guide plate, the first front nut and the first rear nut 10-4 are respectively provided on both sides of the first guide plate, and the first pointer 10-1 is provided on the outside of the first front nut; the first guide plate, the first front nut 10-2, the first rear nut 10-4 and the pointer are connected by bolts;

[0050] The direction indicated by the first pointer 10-1 is always consistent with the chord length direction of the blade 7. By rotating the first pointer 10-1, the installation angle of the upper guide wall 10 can be continuously adjusted.

[0051] The first pointer 10-1 is aligned with the chord length of the blade 7, which can intuitively indicate the installation angle of the upper guide wall 10; with the front and rear nuts, the angle can be quickly locked and fixed after adjustment; the installation angle is continuously adjustable to adapt to the flow field control requirements of different angles of attack and different curvature blades.

[0052] like Figure 5 Preferably, the lower guide wall 11 includes a second guide plate, a second front end nut 11-2, a second rear end nut 11-4, and a second pointer 11-1;

[0053] The lower sidewall 10-3 is provided on the second guide plate, the second front nut and the second rear nut 11-4 are respectively provided on both sides of the second guide plate, and the second pointer 11-1 is provided on the outside of the second front nut; the second guide plate, the second front nut 11-2, the second rear nut 11-4 and the pointer are connected by bolts;

[0054] The direction indicated by the second pointer 11-1 is always consistent with the chord length direction of the blade 7. By rotating the second pointer 11-1, the installation angle of the lower guide wall 11 can be continuously adjusted.

[0055] The lower guide wall 11 adopts the same pointer and nut locking structure as the upper guide wall 10, ensuring symmetrical adjustment and unified operation. The installation angle of the lower guide wall 11 can be adjusted independently and precisely to further optimize the flow state of the lower end wall of the blade cascade and improve the uniformity of the flow field.

[0056] Preferably, the upper guide wall 10 is vertically inserted into the first circular mounting hole 8-1 and the third circular mounting hole 9-1 at both ends; the lower guide wall 11 is vertically inserted into the second circular mounting hole 8-3 and the fourth circular mounting hole 9-3 at both ends.

[0057] The guide wall is inserted vertically into the circular mounting holes at both ends to ensure assembly coaxiality and rotational stability; the installation accuracy is high to avoid jamming or skew during angle adjustment, ensuring stable and reliable flow field control.

[0058] like Figure 6 Preferably, the upper tail plate 12 includes a first plate body, a first support rib 12-1, a second support rib 12-2, and a first clamping bolt 12-3;

[0059] The first plate is a cuboid structure. The first support rib 12-1 and the second support rib 12-2 are respectively connected to the two ends of the first plate. There are two sets of first clamping bolts 12-3, which are respectively threaded into the first support rib 12-1 and the second support rib 12-2.

[0060] The upper tail plate 12 achieves quick installation and angle fixation through supporting ribs and clamping bolts, with a simple structure and high installation and adjustment efficiency; the cuboid plate provides a smooth airflow wall, reduces flow loss, and optimizes the periodicity of the exhaust angle after the grid.

[0061] like Figure 7 Preferably, the lower tail plate 13 includes a second plate, a third support rib 13-1, a fourth support rib 13-2, and a second clamping bolt 13-3.

[0062] The second plate is a cuboid structure. The third support rib 13-1 and the fourth support rib 13-2 are respectively connected to the two ends of the second plate. There are two sets of second clamping bolts 13-3, which are threaded into the third support rib 13-1 and the fourth support rib 13-2 respectively.

[0063] The lower tail plate 13 adopts the same support and fixing structure as the upper tail plate 12. The upper and lower tail plates 13 have the same adjustment method and strong versatility; it is easy to synchronously match the outlet angle of the guide wall to form a continuous and smooth airflow channel.

[0064] Preferably, the lower inlet of the upper tail plate 12 is connected to the lower inlet of the upper guide wall 10, and the upper inlet of the lower tail plate 13 is connected to the upper outlet of the lower guide wall 11.

[0065] The upper and lower tail plates 13 are connected to the corresponding inlet and outlet of the guide wall to ensure a smooth transition of the airflow wall and good sealing performance; reduce local eddies and leakage flow, improve the purity of the two-dimensional flow field, and ensure the accuracy of test data.

[0066] Preferably, the inlets of the upper tailplate 12 and the lower tailplate 13 are both designed with an angle, allowing them to rotate within a certain range around the end of the guide wall, thereby enabling independent adjustment of the tailplate installation angle; expanding the flow field control range and adapting to blade cascade tests under various operating conditions.

[0067] Preferably, there are 7 blades 7, and the distance between the beginning and end of the upper guide wall 10 and the lower guide wall 11 is set as the chord length of the blade 7; the circumferential distance between the lower wall surface of the upper guide wall 10 and the upper wall surface of the lower guide wall 11 and the adjacent blade 7 is the blade cascade pitch; the rotation axis of the upper guide wall 10 and the lower guide wall 11 passes through their beginning and end points; the upper end of the upper guide wall 10 and the lower end of the lower guide wall 11 are non-airflow surfaces.

[0068] By limiting the number of blades, the length of the guide wall, the grid spacing, and the position of the rotation axis, the device structure is standardized and the flow field is more symmetrical; the non-flow surface only needs to ensure strength and weight reduction, thereby reducing processing difficulty and manufacturing cost.

[0069] Preferably, the mounting angles of the upper guide wall 10 and the lower guide wall 11, as well as the mounting angles of the upper tail plate 12 and the lower tail plate 13, are defined with the chord length of the blade 7 as the reference; the thickness of the upper tail plate 12 and the lower tail plate 13 is set to 10 mm; the length of the upper tail plate 12 and the lower tail plate 13 is set to 6 times the chord length of the blade 7; the chamfering degree of the front end of the upper tail plate 12 and the lower tail plate 13 needs to ensure that the upper tail plate 12 and the lower tail plate 13 can rotate ± 20° around the ends of the upper guide wall 10 and the lower guide wall 11, respectively.

[0070] Using the 7th chord length of the blade as the angular reference ensures a unified definition and accurate measurement of the angle; the setting of the tail plate thickness, length and ±20° rotation range takes into account both structural strength and control range, which can significantly improve the post-flush periodicity of the blade cascade at large angles of attack / large camber.

[0071] Preferably, the width of the upper tail plate 12 and the lower tail plate 13 is processed to be less than the height H of the blade 7 by 0.5 mm; the distance between the front and rear support ribs of the upper tail plate 12 and the front and rear side walls of the test section is 1 mm.

[0072] The tail plate width is slightly smaller than the blade height to ensure installation clearance and sealing; a 1mm distance is reserved between the support rib and the side wall to ensure that the clamping nut can be reliably tightened and fixed, ensuring a firm installation without causing assembly interference.

[0073] In summary, this application has the following advantages:

[0074] When applied to conventional planar blade cascade wind tunnel experiments, adjusting the installation angles of the upper and lower guide walls and their coupled upper and lower tail plates can effectively improve the periodicity of the compressor planar blade cascade flow field with large angle of attack and small or large camber. It has the advantages of low experimental cost, low equipment complexity, and easy adjustment.

[0075] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A passive control device for flow field quality in a planar blade cascade wind tunnel, characterized in that, It includes blades (7), front grid plate (8), rear grid plate (9), upper tail plate (12) and lower tail plate (13); The front grating (8) and the rear grating (9) are arranged side by side in the blade grating wind tunnel, and the blades (7) are arranged in multiple sets and spaced vertically between the front grating (8) and the rear grating (9); The upper tail plate (12) and the lower tail plate (13) are arranged vertically and are both connected to the front grid plate (8) and the rear grid plate (9). The upper tail plate (12) is provided with an upper guide wall (10) at the position corresponding to the uppermost blade (7), and the lower tail plate (13) is provided with a lower guide wall (11) at the position corresponding to the lowermost blade (7). The configuration of the lower side wall (10-3) of the upper guide wall (10) and the upper side wall (11-3) of the lower guide wall (11) is designed according to the pressure surface profile of the airfoil being tested.

2. The passive flow field quality control device for a planar blade cascade wind tunnel as described in claim 1, characterized in that, The front grid plate (8) has a first circular mounting hole (8-1) and a second circular mounting hole (8-3) at both ends, the rear grid plate (9) has a third circular mounting hole (9-1) and a fourth circular mounting hole (9-3) at both ends, the upper guide wall (10) is threaded to the first circular mounting hole (8-1) and the third circular mounting hole (9-1) at both ends, and the lower guide wall (11) is threaded to the second circular mounting hole (8-3) and the fourth circular mounting hole (9-3) at both ends. There are gaps between the first circular mounting hole (8-1) and the second circular mounting hole (8-3) and the threaded connection between the upper guide wall (10), the third circular mounting hole (9-1) and the fourth circular mounting hole (9-3) and the lower guide wall (11).

3. The passive flow field quality control device for a planar blade cascade wind tunnel as described in claim 2, characterized in that, The upper guide wall (10) includes a first guide plate, a first front end nut (10-2), a first rear end nut (10-4), and a first pointer (10-1); The lower sidewall (10-3) is provided on the first guide plate, the first front nut and the first rear nut (10-4) are respectively provided on both sides of the first guide plate, and the first pointer (10-1) is provided on the outside of the first front nut; the first guide plate, the first front nut (10-2), the first rear nut (10-4) and the pointer are connected by bolts; The direction indicated by the first pointer (10-1) is always consistent with the chord direction of the blade (7). By rotating the first pointer (10-1), the installation angle of the upper guide wall (10) can be continuously adjusted.

4. The passive flow field quality control device for a planar blade cascade wind tunnel as described in claim 3, characterized in that, The lower guide wall (11) includes a second guide plate, a second front end nut (11-2), a second rear end nut (11-4), and a second pointer (11-1); The lower sidewall (10-3) is provided on the second guide plate, the second front nut and the second rear nut (11-4) are respectively provided on both sides of the second guide plate, and the second pointer (11-1) is provided on the outside of the second front nut; the second guide plate, the second front nut (11-2), the second rear nut (11-4) and the pointer are connected by bolts; The direction indicated by the second pointer (11-1) is always consistent with the chord direction of the blade (7). By rotating the second pointer (11-1), the installation angle of the lower guide wall (11) can be continuously adjusted.

5. The passive flow field quality control device for a planar blade cascade wind tunnel as described in claim 4, characterized in that, The upper guide wall (10) is vertically inserted into the first circular mounting hole (8-1) and the third circular mounting hole (9-1) at both ends; the lower guide wall (11) is vertically inserted into the second circular mounting hole (8-3) and the fourth circular mounting hole (9-3) at both ends.

6. The passive flow field quality control device for a planar blade cascade wind tunnel as described in claim 1, characterized in that, The upper tail plate (12) includes a first plate body, a first support rib (12-1), a second support rib (12-2), and a first clamping bolt (12-3); The first plate is a cuboid structure. The first support rib (12-1) and the second support rib (12-2) are respectively connected to the two ends of the first plate. There are two sets of the first clamping bolts (12-3) and they are respectively threaded into the first support rib (12-1) and the second support rib (12-2).

7. The passive flow field quality control device for a planar blade cascade wind tunnel as described in claim 6, characterized in that, The lower tail plate (13) includes a second plate, a third support rib (13-1), a fourth support rib (13-2), and a second clamping bolt (13-3); The second plate is a cuboid structure. The third support rib (13-1) and the fourth support rib (13-2) are respectively connected to the two ends of the second plate. There are two sets of the second clamping bolts (13-3), which are threaded into the third support rib (13-1) and the fourth support rib (13-2) respectively.

8. The passive control device for wind tunnel flow field quality of planar blade cascade as described in claim 7, characterized in that, The lower inlet of the upper tail plate (12) is connected to the lower inlet of the upper guide wall (10), and the upper inlet of the lower tail plate (13) is connected to the upper outlet of the lower guide wall (11).

9. The passive flow field quality control device for a planar blade cascade wind tunnel as described in claim 7, characterized in that, The inlets of both the upper tailplate (12) and the lower tailplate (13) are designed with an angle.

10. The passive flow field quality control device for a planar blade cascade wind tunnel as described in claim 7, characterized in that, The number of blades (7) is 7. The distance between the beginning and end of the upper guide wall (10) and the lower guide wall (11) is set as the chord length of the blade (7). The circumferential distance between the lower wall surface of the upper guide wall (10) and the upper wall surface of the lower guide wall (11) and the adjacent blade (7) is the blade cascade pitch. The rotation axis of the upper guide wall (10) and the lower guide wall (11) passes through their beginning ends. The upper end of the upper guide wall (10) and the lower end of the lower guide wall (11) are non-airflow surfaces.

11. The passive control device for the flow field quality of a planar blade cascade wind tunnel as described in claim 7, characterized in that, The mounting angles of the upper guide wall (10) and the lower guide wall (11), as well as the mounting angles of the upper tail plate (12) and the lower tail plate (13), are defined with the blade chord length direction as the reference. The thickness of the upper tail plate (12) and the lower tail plate (13) is set to 10 mm. The length of the upper tail plate (12) and the lower tail plate (13) is set to 6 times the blade chord length. The chamfering degree of the leading end of the upper tail plate (12) and the lower tail plate (13) needs to ensure that the upper tail plate (12) and the lower tail plate (13) can rotate around the ends of the upper guide wall (10) and the lower guide wall (11), respectively. 20°.

12. The passive control device for wind tunnel flow field quality of planar blade cascade as described in claim 7, characterized in that, The width of the upper tail plate (12) and the lower tail plate (13) is processed to be less than the blade height H by 0.5 mm; the distance between the supporting ribs of the upper tail plate (12) and the front and rear side walls of the test section is 1 mm.

Images