A multi-diffuser inlet section inner-diffuser flow field configuration device

Abstract

A flow field construction device for a multi-duct inlet section is disclosed. A rectifier cone is fixed to the front end of a mandrel, an inner casing is fitted outside the mandrel with its rear end extending outwards, a duct baffle divides the inner and outer ducts, a front row of guide vanes is located near the rectifier cone at the front end of the mandrel, a rear row of guide vanes is located behind the front row of guide vanes, a honeycomb unit is fixed inside the inner duct behind the rear row of guide vanes, fixed guide vanes are located inside the inner duct behind the honeycomb unit, adjustable guide vanes are located inside the inner duct behind the fixed guide vanes, a notch is opened in the corresponding area of ​​the inner casing to allow the adjustable guide vanes to rotate, an adjuster is installed with the adjustable guide vanes and connected to a stepper motor for transmission, an outer casing is spaced outside the duct baffle, and an experimental section casing is fixed to the rear end of the inner casing. This device can change the inlet angle of attack of the experimental specimen according to experimental conditions, increasing the wind tunnel outlet velocity and reducing the total pressure while maintaining the same wind tunnel output power.

Description

Technical Field

[0001] This invention relates to a flow field construction device, and more particularly to a flow field construction device for a multi-duct inlet section, belonging to the field of transonic wind tunnel outlet flow field construction technology. Background Technology

[0002] To meet the requirements of high pressure and low weight in gas turbine compressors, modern compressor blades often employ a small diameter-to-height ratio. This results in a higher circumferential velocity near the blade tip and a lower circumferential velocity at the root, leading to a large radial gradient distribution of parameters such as the incoming Mach number and airflow angle. In wind tunnel experiments, to achieve inlet conditions with a large radial gradient distribution of parameters like the Mach number without rotating the blade test specimen, a multi-duct inlet section can be added in front of the test specimen.

[0003] Because the inflow at the wind tunnel exit is relatively uniform, the internal duct flow field needs to be accelerated and depressurized after adopting a multi-duct inlet section to achieve a low Mach number and low total pressure flow field parameter distribution at the root of the small-diameter high-specific-weight blade cascade. It should be noted that "low Mach" here refers to the external duct, but it is higher than the Mach number at the wind tunnel exit; therefore, the wind tunnel exit still needs to be accelerated. To this end, a multi-duct inlet section external duct acceleration device is designed to increase the Mach number at the exit of the internal duct while reducing the total pressure within the internal duct.

[0004] Currently, no technical solution has been proposed to increase speed while reducing total pressure without changing wind tunnel output power. Therefore, a multi-duct inlet flow field construction device is essential to increase wind tunnel exit speed and reduce total pressure in order to realize small-diameter high-ratio blade wind tunnel experiments. Summary of the Invention

[0005] To address the shortcomings of the prior art, this invention provides a multi-duct inlet section duct flow field construction device. It adopts a straight cylindrical design for the inner casing, duct baffle, and outer casing, and sequentially arranges a front row of guide vanes, a rear row of guide vanes, a honeycomb structure, fixed guide vanes, and adjustable guide vanes. The adjustable guide vanes can adjust the installation angle according to experimental conditions, thereby changing the inlet angle of attack of the experimental specimen, achieving the purpose of increasing the wind tunnel outlet velocity and reducing the total pressure while keeping the wind tunnel output power constant.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a multi-duct inlet section flow field construction device, comprising a rectifier cone, an inner casing, a duct baffle, a front guide vane, a rear guide vane, a honeycomb unit, fixed guide vanes, adjustable guide vanes, an adjuster, a mandrel, a stepper motor, an outer casing, and an experimental section casing. The rectifier cone is coaxially fixed to the front end of the mandrel. The inner casing is a cylindrical structure tightly fitted onto the outside of the mandrel and connected to the rectifier cone. Its rear end extends outward and is provided with a partition to form a cavity for installing the adjuster. The duct baffle is a cylindrical structure coaxially spaced between the inner casing and the outer casing to divide the inner duct and the outer duct. Its welding is fixed... The front and rear guide vanes are positioned at their mid-diameter. The front guide vane consists of multiple blades arranged at equal angles around the core shaft and located near the front end of the core shaft, adjacent to the rectifier cone. Its inner end is welded to the core shaft, and its outer end passes through the inner casing and duct partition and is welded to the outer casing. The rear guide vane consists of multiple blades arranged at equal angles around the core shaft and located behind the front guide vane. Its inner end is welded to the inner casing, and its outer end passes through the duct partition and is welded to the outer casing. The honeycomb unit is fixed inside the inner duct behind the rear guide vane and consists of four rows of radially staggered cylinders. Each row of cylinders is evenly distributed circumferentially. Oriented parallel to the mandrel axis, the fixed guide vane is located behind the honeycomb inside the inner channel. It consists of multiple blades arranged at equal angles around the mandrel. The inner end is welded to the inner casing, and the outer end is welded to the duct partition. The adjustable guide vane is located behind the fixed guide vane inside the inner channel. It consists of multiple blades arranged at equal angles around the adjuster. A rotating shaft is provided at the root with a through hole and two pin holes that pass through both sides laterally. The inner casing and the corresponding area of ​​the adjustable guide vane have corresponding notches along the circumference to allow the adjustable guide vane to rotate. The adjuster includes a drive shaft and a turntable coaxially disposed at its end. The outer surface edge of the turntable... The adjustable guide vanes are evenly arranged around their circumference with a number of connecting ears corresponding to the number of blades. Each connecting ear is hinged to the end of the connecting rod. Each connecting rod is fitted with a sleeve. The adjustable guide vanes are inserted into the corresponding sleeves through the perforations. The shaft and the sleeve are connected and positioned by pins at the two pin holes. The output shaft of the stepper motor is connected to the transmission shaft through a coupling. The outer casing is a cylindrical structure and is coaxially spaced outside the duct partition. The experimental section casing is fixed to the rear end of the inner casing. The experimental section casing is horn-shaped with its horn opening facing the rear end. The housing of the stepper motor is connected and fixed to the experimental section casing.

[0007] Compared with the prior art, the beneficial effects of the present invention are as follows: The inner casing, duct baffle and outer casing of the present invention adopt a straight cylindrical design to ensure that the size of the wind tunnel outlet and the test section outlet are matched. In the past, the acceleration section often adopted a conical curve for convergence design, which led to the experimental piece needing to be scaled down to match the acceleration section outlet. The straight cylindrical design helps to control a series of design costs. The honeycomb design ensures that the turbulence reduces the total pressure while increasing the stability of the flow. Crucially, the series design of fixed guide vanes and adjustable guide vanes increases the flow velocity and allows the installation angle of the adjustable guide vanes to be adjusted according to the experimental conditions, thereby changing the inlet angle of attack of the experimental piece. Furthermore, the regulator is installed in the inner casing, which realizes the adjustment of the inner duct adjustable guide vanes while increasing the space utilization of the device. Attached Figure Description

[0008] Figure 1 This is a cross-sectional structural schematic diagram of the present invention;

[0009] Figure 2 This is a front view of the adjustable guide vane of the present invention;

[0010] Figure 3 This is a left view of the adjustable guide vane of the present invention;

[0011] Figure 4 This is an isometric view of the drive structure of the regulator of the present invention;

[0012] Figure 5 This is an isometric view of the assembly structure of the adjustable guide vane and regulator of the present invention. Detailed Implementation

[0013] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0014] like Figures 1-5 As shown, a multi-duct inlet section flow field construction device includes a rectifier cone 1, an inner casing 2, a duct baffle 3, a front guide vane 4, a rear guide vane 5, a honeycomb unit 6, fixed guide vanes 7, adjustable guide vanes 8, an adjuster 9, a spindle 10, a stepper motor 17, an outer casing 20, and an experimental section casing 21.

[0015] Combination Figure 1 As shown, the rectifier cone 1 is coaxially fixed to the front end of the spindle 10, guiding the airflow passing through the surface of the rectifier cone 1 into the inner duct and the outer duct to reduce the blockage rate.

[0016] Combination Figure 1As shown, the inner casing 2 is a cylindrical structure that is tightly fitted to the outside of the spindle 10 and fastened to the rectifier cone 1 by a threaded connection. The rear end of the inner casing 2 extends outward to the end of the spindle 10 and is provided with a partition to form a cavity for installing the regulator 9.

[0017] Combination Figure 1 As shown, the duct baffle 3 is a cylindrical structure coaxially spaced between the inner casing 2 and the outer casing 20, dividing the space between the duct baffle 3 and the inner casing 2 into an inner duct, and the space between the duct baffle 3 and the outer casing 20 into an outer duct. It is fixed to the middle diameter of the front guide plate 4 and the rear guide plate 5 by welding.

[0018] Combination Figure 1 As shown, the front guide plate 4 is located at the front end of the spindle 10 near the rectifier cone 1. It is composed of multiple blades arranged at equal angles around the spindle 10. The number of blades is preferably 4, arranged in a cross shape. The inner end of the front guide plate 4 is welded and fixed to the spindle 10, and the outer end of the front guide plate 4 passes through the inner casing 2 and the duct partition 3 and is welded and fixed to the outer casing 20. It is used to guide the airflow to move axially and at the same time to reinforce the inner casing 2.

[0019] Combination Figure 1 As shown, the rear guide vane 5 is located behind the front guide vane 4. It is composed of multiple blades arranged at equal angles around the spindle 10. The number of blades is preferably 4, arranged in an X-shape. The inner end of the rear guide vane 5 is welded and fixed to the inner casing 2, and the outer end of the rear guide vane 5 passes through the duct partition 3 and is welded and fixed to the outer casing 20. This ensures that the airflow after being rectified by the front guide vane 4 continues to flow smoothly along the axial direction, and also reinforces the inner casing 2.

[0020] Combination Figure 1 As shown, the honeycomb unit 6 is fixed to the rear side of the rear guide plate 5 inside the inner channel. It consists of four rows of cylinders arranged radially in a staggered manner. Each row of cylinders is evenly distributed circumferentially and is oriented parallel to the axis of the spindle 10. This is used to turbulent the flow, reduce the total pressure of the incoming flow, and ensure that the incoming flow maintains a stable axial flow.

[0021] Combination Figure 1 As shown, the fixed guide vane 7 is located behind the honeycomb unit 6 inside the inner duct. It consists of multiple blades arranged at equal angles around the core shaft 10. The number of blades is preferably 48. The inner end of the fixed guide vane 7 is welded and fixed to the inner casing 2, and the outer end of the fixed guide vane 7 is welded and fixed to the duct partition 3 to accelerate the incoming flow.

[0022] Combination Figures 1-3As shown, the adjustable guide vane 8 is located behind the fixed guide vane 7 inside the inner duct. It consists of multiple blades arranged at equal angles around the regulator 9. The number of blades is preferably 48. A rotating shaft 11 is provided at the root of the adjustable guide vane 8. The rotating shaft 11 has a through hole 23 and two pin holes 22 that pass through its two sides laterally for connection with the regulator 9. The inner casing 2 and the area corresponding to the adjustable guide vane 8 have corresponding number of notches along the circumference to allow the regulator 9 to rotate the adjustable guide vane 8 at a certain angle. There is a gap between the outer end of the adjustable guide vane 8 and the duct partition 3.

[0023] Combination Figures 1-3 and Figure 5 As shown, the regulator 9 includes a drive shaft 18 and a turntable 14 coaxially disposed at its end. Multiple connecting ears 15 are evenly arranged along the circumference of the outer surface edge of the turntable 14. The number of connecting ears 15 corresponds to the number of blades of the adjustable guide vane 8. Each connecting ear 15 is hinged to the end of a connecting rod 13. Each connecting rod 13 can swing at a certain angle in the tangential direction of the turntable 14 with the corresponding connecting ear 15 as the axis. A sleeve 12 is fitted on each connecting rod 13. The adjustable guide vane 8 is inserted into the corresponding sleeve 12 through the through hole 23 on the rotating shaft 11. The rotating shaft 11 and the sleeve 12 are connected and positioned by pins at two pin holes 22. The rotating shaft 11 of the adjustable guide vane 8 is restricted to the corresponding notch in the inner casing 2.

[0024] Combination Figure 1 As shown, the mandrel 10 is located at the center of the entire device and is used for mounting and installing the connected components.

[0025] Combination Figure 1 and Figure 4 As shown, the stepper motor 17 is used to drive the regulator 9 with adjustable guide vanes 8 to rotate forward and backward at a certain angle. The output shaft of the stepper motor 17 is connected to the transmission shaft 18 through a coupling 16. The rear end fixed shaft seat 19 of the inner casing 2 is mounted on the transmission shaft 18. The housing of the stepper motor 17 is connected and fixed to the experimental section casing 21.

[0026] Combination Figure 1 As shown, the outer casing 20 is a cylindrical structure coaxially spaced outside the duct partition 3, and its positioning is achieved by the front guide plate 4 and the rear guide plate 5.

[0027] Combination Figure 1 As shown, the experimental section casing 21 is horn-shaped and is coaxially fixedly connected to the shaft seat 19. The horn-shaped side of the experimental section casing 21 faces the rear end and is covered by the stepper motor 17.

[0028] In practical applications, the airflow in the wind tunnel is guided into the inner duct by the rectifier cone 1. After flowing through the front guide vane 4 and the rear guide vane 5, the flow direction is integrated into the axial direction. Then it enters the honeycomb 6. When flowing through the honeycomb 6, the boundary layer effect is generated, which leads to an increase in turbulence loss and a decrease in total pressure and velocity. The structure of the honeycomb 6 has a guiding effect on the airflow, and the flow still maintains the axial flow. Finally, it enters the flow channel of the fixed guide vane 7 and the adjustable guide vane 8. In the expansion channel formed by the fixed guide vane 7 and the adjustable guide vane 8, the airflow expands and accelerates. Finally, the airflow velocity is increased and the total pressure is reduced at the outlet. This realizes the construction of the flow field at the root of the inlet of the small-diameter high-specific-pressure aero blade under the experimental condition that the blade is stationary. The inner casing 2, duct baffle 3, and outer casing 20 adopt a straight cylindrical design to ensure that the dimensions of the wind tunnel outlet and the test section outlet are matched; the design of the honeycomb device 6 ensures that the turbulence reduces the total pressure while increasing the stability of the flow; the series design of the fixed guide vane 7 and the adjustable guide vane 8 increases the flow velocity while ensuring the adjustability of the inlet angle of attack of the test piece; the regulator 9 is installed in the inner casing 2, which realizes the adjustment of the inner duct adjustable guide vane 8 while increasing the space utilization of the device. The adjustable guide vane 8 is powered by a stepper motor 17 and its installation angle can be adjusted. The principle is as follows: while the stepper motor 17 drives the transmission shaft 18 to rotate at a certain angle with the turntable 14, the connecting rod 13 connected to the connecting ear 15 on the turntable 14 rotates accordingly. Due to the displacement limitation of the adjustable guide vane 8, the connecting rod 13 is resisted at the connection with the sleeve 12 and gives the adjustable guide vane 8 a rotational torque through the reaction force. During this process, the rotating shaft 11 of the adjustable guide vane 8 is close to the edge of the corresponding notch in the inner casing 2, and the connecting rod 13 swings and deflects along the tangent direction of the turntable 14 with the connecting ear 15 as the axis, thereby changing the installation angle of the adjustable guide vane 8. Thus, according to the experimental requirements, the airflow angle at the outlet can be adjusted by the adjustable guide vane 8. The adjustment range of the installation angle of the adjustable guide vane 8 should be controlled within ±45°. The ratio of the rotation angle of the stepper motor 17 to the change angle of the installation angle of the adjustable guide vane 8 is 1:1.36.

[0029] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of the equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0030] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A flow field structure device for a multi-duct inlet section, characterized in that: The system includes a rectifier cone (1), an inner casing (2), a duct baffle (3), a front guide vane (4), a rear guide vane (5), a honeycomb structure (6), fixed guide vanes (7), adjustable guide vanes (8), an adjuster (9), a spindle (10), a stepper motor (17), an outer casing (20), and an experimental section casing (21). The rectifier cone (1) is coaxially fixed to the front end of the spindle (10). The inner casing (2) is a cylindrical structure that is tightly fitted to the outside of the spindle (10) and connected to the rectifier cone (1). Its rear end extends outward and is equipped with a partition to form a cavity for installing the adjuster (9). The duct baffle (3) is a cylindrical structure that is coaxially spaced between the inner casing (2) and the outer casing (20) to divide the inner duct and the outer duct. Fixed at the mid-diameter of the front guide plate (4) and the rear guide plate (5), the front guide plate (4) is composed of multiple blades arranged at equal angles around the core shaft (10) and located near the front end of the core shaft (10) adjacent to the rectifier cone (1). Its inner end is welded to the core shaft (10), and its outer end passes through the inner casing (2) and the duct partition (3) and is welded to the outer casing (20). The rear guide plate (5) is composed of multiple blades arranged at equal angles around the core shaft (10) and located behind the front guide plate (4). Its inner end is welded to the inner casing (2), and its outer end passes through the duct partition (3) and is welded to the outer casing (20). The honeycomb unit (6) is fixed inside the inner duct behind the rear guide plate (5), and it consists of four blades. The inner casing is composed of rows of cylinders arranged radially in a staggered manner. Each row of cylinders is evenly distributed circumferentially and oriented parallel to the axis of the mandrel (10). The fixed guide vane (7) is located behind the honeycomb unit (6) inside the inner casing. It consists of multiple blades arranged at equal angles around the mandrel (10). The inner end is welded and fixed to the inner casing (2), and the outer end is welded and fixed to the duct partition (3). The adjustable guide vane (8) is located behind the fixed guide vane (7) inside the inner casing. It consists of multiple blades arranged at equal angles around the adjuster (9). The root is provided with a rotating shaft (11) with a through hole (23) and two pin holes (22) that pass through its two sides laterally. The corresponding area of ​​the inner casing (2) and the adjustable guide vane (8) has a corresponding number of notches along the circumferential direction to allow for... The guide vane (8) rotates. The adjuster (9) includes a drive shaft (18) and a turntable (14) coaxially disposed at its end. Connecting ears (15) corresponding to the number of blades of the adjustable guide vane (8) are evenly arranged along the circumference of the outer surface edge of the turntable (14). Each connecting ear (15) is hinged to the end of the connecting rod (13). A sleeve (12) is fitted on each connecting rod (13). The adjustable guide vane (8) is inserted into the corresponding sleeve (12) through the through hole (23). The rotating shaft (11) and the sleeve (12) are connected and positioned by pins at the two pin holes (22). The output shaft of the stepper motor (17) is connected to the drive shaft (18) through a coupling (16) for transmission.The outer casing (20) is a cylindrical structure coaxially spaced outside the duct partition (3). The experimental section casing (21) is fixed to the rear end of the inner casing (2). The experimental section casing (21) is horn-shaped with its horn opening facing the rear end. The housing of the stepper motor (17) is connected and fixed to the experimental section casing (21). While the stepper motor (17) drives the transmission shaft (18) and the turntable (14) to rotate, the connecting rod (13) connected by the connecting lug (15) on the turntable (14) rotates accordingly, subject to the adjustable guide vanes. (8) Due to displacement limitation, the connecting rod (13) experiences resistance at its connection with the sleeve (12), and provides rotational torque to the adjustable guide vane (8) through reaction force. During this process, the rotating shaft (11) of the adjustable guide vane (8) rests against the corresponding notch edge of the inner casing (2), while the connecting rod (13) swings and deflects along the tangent direction of the turntable (14) with the connecting lug (15) as the axis, thus changing the installation angle of the adjustable guide vane (8). Therefore, the airflow angle at the outlet can be adjusted through the adjustable guide vane (8) according to the experimental requirements.

2. The multi-duct inlet section internal duct flow field construction device according to claim 1, characterized in that: The front guide vane (4) has four blades arranged in a cross shape.

3. The multi-duct inlet section internal duct flow field construction device according to claim 1, characterized in that: The rear guide vane (5) has four blades arranged in an X-shape.

4. The flow field construction device for a multi-duct inlet section according to claim 1, characterized in that: The fixed guide vane (7) has 48 blades.

5. The flow field construction device for a multi-duct inlet section according to claim 1, characterized in that: The adjustable guide vane (8) has 48 blades.

6. The flow field construction device for a multi-duct inlet section according to claim 1, characterized in that: The rear end of the inner casing (2) is fixed with a bearing seat (19) and mounted on the drive shaft (18). The experimental section casing (21) is coaxially fixedly connected with the bearing seat (19).

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