Flow tube test bench and testing method thereof

Abstract

The present invention provides a flow tube test bench and a test method thereof, which relate to the field of flow tube experiments and aim to solve the technical problem of difficulty in conveniently and accurately measuring the flow velocity and acoustic parameters of a two-dimensional physical field under conditions of wide-speed flow and wide-frequency sound sources. The flow tube test bench includes a flow measurement unit, an acoustic measurement unit, and a sound source unit, and the flow measurement unit, the acoustic measurement unit, and the sound source unit are detachably connected to each other; the flow measurement unit includes a first pipe and a flow channel measurement device provided in the first pipe, and the flow channel measurement device is used for flow measurement at a two-dimensional cross section of the first pipe; the acoustic measurement unit includes a second pipe and an acoustic liner measurement device provided in the second pipe, and the acoustic liner measurement device is used for acoustic measurement of the acoustic liner; the sound source unit includes at least one third pipe and a sound source device provided in the third pipe, and the sound source device is used to generate a broadband sound source. The flow tube test bench is used for acoustic experiments on flow channels with wide-speed flow.

Description

Technical Field

[0001] The present disclosure relates to the field of flow tube experiments, and in particular to a flow tube test bench and a testing method thereof. Background Art

[0002] Flow tube test benches are essential equipment for acoustic lining research and extraction method development. However, due to structural issues, existing flow tube test benches, both domestically and internationally, struggle to conduct high-velocity experiments exceeding Mach 0.2. Furthermore, flow tube test benches must simultaneously measure both flow velocity and acoustics. In existing structures, the flow velocity measurement device disrupts the flow of air within the flow channel, resulting in inaccurate subsequent acoustic measurements. Furthermore, flow velocity measurements in existing flow tube test benches struggle to accurately measure the actual flow velocity within the flow channel. Summary of the Invention

[0003] The purpose of the present invention is to provide a flow tube test bench and testing method to solve the problem of difficulty in conveniently and accurately measuring the flow velocity and acoustic parameters of a two-dimensional physical field under conditions of wide-speed flow and broadband sound source.

[0004] In order to achieve the above object, the present invention provides the following technical solutions:

[0005] An embodiment of the present invention provides a flow tube test bench for acoustic experiments in a flow channel with a wide velocity range. The flow tube test bench includes a flow measurement unit, an acoustic measurement unit, and a sound source unit. The flow measurement unit, the acoustic measurement unit, and the sound source unit are detachably connected.

[0006] The flow measurement unit includes a first pipe and a flow channel measurement device provided in the first pipe, wherein the flow channel measurement device is used for flow measurement at a two-dimensional cross section of the first pipe;

[0007] The acoustic measurement unit includes a second pipe and an acoustic liner measuring device provided in the second pipe, wherein the acoustic liner measuring device is used for acoustic measurement of the acoustic liner;

[0008] The sound source unit includes at least one third pipe and a sound source device arranged in the third pipe, and the sound source device is used to generate a broadband sound source.

[0009] Compared to existing technologies, the flow tube test bench provided by the present invention can withstand flows in a wide range of speeds from 0 to 0.99 Mach and high-intensity acoustic environments. It is sealed to prevent leakage caused by high internal and external pressure differentials, enabling accurate broadband measurements of acoustic linings. The flow measurement unit of the present invention can conveniently measure the flow velocity of a two-dimensional physical field through a displacement mechanism. Furthermore, the flow channel measurement device can achieve two-dimensional cross-sectional flow velocity measurements of a first pipeline, and then remove the test device from the first pipeline to avoid affecting the fluid in the flow channel, thereby making the acoustic measurement results more accurate.

[0010] Another object of the present invention is to provide a flow tube measurement method, which is applied to the above-mentioned test bench, and the measurement method comprises:

[0011] The first electromagnet and the second electromagnet are energized, and the third linear motion mechanism drives the probe to measure the flow parameters of the first target point;

[0012] The first electromagnet is powered off and the second electromagnet is powered on, the second linear motion mechanism drives the probe to the second target point, the first electromagnet is powered on, and the probe measures the flow parameters of the second target point;

[0013] When the measurement of all target points is completed, the first electromagnet is powered off, the first linear motion mechanism drives the first cover plate and the second cover plate to separate, and the third linear motion mechanism retracts the probe into the dark box;

[0014] The first electromagnet is powered off, and the second linear motion mechanism covers the non-porous portion of the first cover plate or the second cover plate on the opening.

[0015] Compared with the prior art, the measurement method of the present invention has the following advantages:

[0016] The flow tube measurement method has the same advantages as the flow channel test bench described above over the prior art, and will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings illustrate exemplary embodiments of the present disclosure and together with the description serve to explain the principles of the present disclosure. These drawings are included to provide a further understanding of the present disclosure and are incorporated in and constitute a part of this specification.

[0018] Figure 1 It is a perspective schematic diagram of a flow tube test bench according to an embodiment of the present disclosure.

[0019] Figure 2 This is a three-dimensional schematic diagram of a flow tube test bench according to another embodiment of the present disclosure.

[0020] Figure 3 Schematic diagram of the three-dimensional structure of a flow channel measurement device according to an embodiment of the present disclosure.

[0021] Figure 4 yes Figure 3 Schematic diagram of the front view.

[0022] Figure 5 yes Figure 3 Schematic top view of .

[0023] Figure 6 Schematic diagram of a first pipeline structure with an opening according to an embodiment of the present disclosure.

[0024] Figure 7 4 is a schematic structural diagram of a first cover plate according to an embodiment of the present disclosure.

[0025] Figure 8 yes Figure 7 Partial cross-sectional view.

[0026] Figure 9 4 is a schematic structural diagram of a second cover plate according to an embodiment of the present disclosure.

[0027] Figure 10 3 is a schematic structural diagram of a first cover plate and a probe portion according to an embodiment of the present disclosure.

[0028] Figure 11 Schematic diagram of the three-dimensional structure of the acoustic liner measuring device according to an embodiment of the present disclosure.

[0029] Figure 12 is an exploded schematic diagram of a mount according to an embodiment of the present disclosure.

[0030] Figure 13 2 is a schematic diagram of assembling a first tool and a microphone according to an embodiment of the present disclosure.

[0031] Figure 14 2 is a schematic cross-sectional view of a first tooling according to an embodiment of the present disclosure.

[0032] Figure 15 2 is a schematic cross-sectional view of a second tooling according to an embodiment of the present disclosure.

[0033] Figure 16 It is a partial cross-sectional schematic diagram of the second tooling and the second pipeline according to an embodiment of the present disclosure.

[0034] Figure 17 yes Figure 11 Schematic diagram of the cross-section structure.

[0035] Figure 18 It is a perspective schematic diagram of a receiver according to an embodiment of the present disclosure.

[0036] Figure 19 2 is a bottom view schematic diagram of a second pipeline according to an embodiment of the present disclosure.

[0037] Figure 20 2 is a schematic cross-sectional view of a mounting base and microphone combination according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0038] The present disclosure will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only intended to explain the relevant content and are not intended to limit the present disclosure. It should also be noted that, for ease of description, only the portions relevant to the present disclosure are shown in the accompanying drawings.

[0039] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in the present disclosure may be combined with each other. The present disclosure will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0040] like Figure 1-Figure 3 、 Figure 11 As shown, the flow tube test bench of an embodiment of the present invention is used for acoustic experiments of flow channels with wide-speed range flows. The flow tube test bench includes a flow measurement unit A, an acoustic measurement unit B and a sound source unit C. The flow measurement unit A, the acoustic measurement unit B and the sound source unit C are detachably connected. The flow measurement unit A includes a first pipe 20 and a flow channel measurement device provided in the first pipe 20, and the flow channel measurement device is used for flow measurement at a two-dimensional cross-section of the first pipe 20. The acoustic measurement unit includes a second pipe 910 and an acoustic liner measurement device provided in the second pipe 910, and the acoustic liner measurement device is used for acoustic measurement of the acoustic liner. The sound source unit C includes at least one third pipe and a sound source device provided in the third pipe, and the sound source device is used to generate a broadband sound source.

[0041] In some embodiments, the detachable connections between the flow measurement unit A, acoustic measurement unit B, and sound source unit C enable the entire flow tube test bench to adopt a modular design, allowing for easy assembly. The connections between the various units are sealed, enabling accurate measurements under high-speed flow conditions. Furthermore, noise reduction treatment is implemented at both the inlet and outlet of the pipe to prevent impacting the accuracy of the measurements made by the acoustic measurement unit B.

[0042] The modular design allows for arbitrary combinations of units, such as Figure 1 As shown, the flow measurement unit A can be set at any position to measure the flow parameters at multiple cross sections and the fluid velocity upstream or downstream of the acoustic measurement unit B. Figure 2 As shown, one or more sound source devices in the sound source unit C are movable and, in combination with the flow measurement unit A and the acoustic measurement unit B, can obtain the forward and backward flow and sound fields. Furthermore, one of the sound source devices can be replaced with a light wall segment, and the remaining two sound source devices can be moved upstream and downstream of the acoustic measurement segment, respectively, to obtain a combined forward and backward sound field. Acoustic measurement unit B can then monitor the forward and reverse sound transmission modes and noise reduction upstream and downstream of the sound lining. It will be understood that the above-described combinations of units are merely exemplary, and in certain embodiments, the positional relationships between the units are not limited.

[0043] It is understood that the sound source unit C may include multiple sound source devices. Each sound source device may include three speakers on each sidewall of the third conduit. Increasing the number of sound source devices, as needed, may yield a higher-intensity sound source, while increasing or decreasing the number may yield a broadband sound source. When multiple sound source devices are present, one of the sound source devices may be replaced with a non-destructive rigid wall segment to minimize the impact of the speaker openings on the flow.

[0044] In some embodiments, the first, second, and third pipes are connected via flanges, and the two connected flanges are positioned with locating pins. The locating pins are used to ensure that the inner walls of the pipes are flush. Specifically, one of the connected flanges has a tapered locating pin, and the other flange has a tapered locating hole that matches the tapered locating pin. When the two flanges are connected, the locating pins ensure that the inner walls of the pipes are flush. It is understood that to ensure a seal, a sealing ring is also provided between the connected flanges to ensure accurate flow channel measurement.

[0045] In fact, the sealed shell on the outside of the flow measuring device is used to seal the flow measuring device. The shell is connected to the first pipe with bolts, and the shell, the first pipe, and the shell are sealed with a sealing ring. The threaded hole on the shell is used to lead out the wires of the measuring device. The hole can be blocked with a plug with a thread to ensure the seal. The sealed shell is set on the flow measuring device to prevent leakage caused by poor sealing of the flow measuring device, and the use of the shell for secondary sealing can ensure the sealing of the first pipe. For example, when the flow measuring device is not sealed tightly, when the pressure in the shell is consistent with the pressure in the first pipe, it can also play a similar sealing role.

[0046] In order to realize the two-dimensional measurement of the flow field probe in the first pipe, the wall surface on which the probe is set needs to be made into a slide that moves in a direction perpendicular to the length of the first pipe. However, the wall surface of the first pipe is sealed in the form of a sealing ring, and a downward pressure is required to press the slide onto the first pipe. The friction force formed cannot make the slide slide, making it impossible for the flow field measurement to be both sealed and convenient.

[0047] See also Figures 3 to 6As shown, an embodiment of the present invention provides a flow channel measuring device for multi-point measurement of a flow channel, the measuring device includes a probe 40, a slide 10 and a first pipe 20 forming a flow channel, the first wall 21 of the first pipe 20 has an opening, the opening forms two side end surfaces 211 on the first wall 21, the side end surfaces 211 are first inclined surfaces that reduce the diameter of the opening from the outside to the inside, and from the outside to the inside refers to the direction from the outer surface of the first wall 21 to the inner wall, the opening forms bottom end surfaces 212 on the two side wall surfaces 22 of the first pipe 20, and the bottom end surfaces 212 are respectively connected to the bottom end surfaces 212. The inner wall of the first wall surface 21 is flush, and both side end surfaces 211 and both bottom end surfaces 212 are provided with first grooves 213 for accommodating the fifth sealing ring. The slide 10 is coordinated with the opening to form a closed flow channel for the first pipe 20. The slide 10 has an inclined surface that matches the first inclined surface. The slide 10 is slidably disposed in the opening, and the probe 40 can be moved through the slide 10 and extend into the flow channel. A force-applying device is provided on the outer side of at least one side wall surface 22. The force-applying device can be a first electromagnet 31, which attracts the slide 10 to press it against the opening. The force-applying device can also be other devices that press the slide against the first pipe opening, such as a linear motor, a hydraulic cylinder, or a pneumatic cylinder.

[0048] When performing multi-point measurements on the flow channel, such as measuring within a single cross-section of the flow channel, the probe 40 needs to be moved multiple times while ensuring the tightness of the first pipe. An opening is formed on the first wall 21 of the first pipe 20. The depth of the opening is consistent with the thickness of the first wall 21, so that the bottom surface of the slide 10 and the inner wall of the first wall 21 form a complete plane. The opening forms two opposing side end surfaces 211 on the first wall 21 of the first pipe, and two opposing bottom end surfaces 212 on the two side wall surfaces 22 of the first pipe. The side wall surfaces 22 are two wall surfaces adjacent to the first wall 21, wherein the side end surfaces 211 are first inclined surfaces that gradually slope downward toward the center of the opening. The two opposite side end faces 211 and the two opposite bottom end faces 212 serve as the slideway of the skateboard 10. A first groove 213 is also provided on the slideway. A fifth sealing ring for sealing is provided in the first groove 213. The corresponding positions of the skateboard 10 and the two opposite side end faces 211 have inclined surfaces that cooperate with the first inclined surfaces. When a downward pressing force is applied to the skateboard 10, the fifth sealing ring at the first inclined surface is subjected to both downward pressure and side pressure, thereby ensuring sealing. At the same time, the skateboard and the first pipe adopt inclined surface cooperation, which can make the inner wall of the first wall surface 21 form a complete plane.

[0049] On the outside of the side wall 22, below the slide 10, a first electromagnet 31 is provided. The first electromagnet 31 can also be provided in two pieces, one on each side wall 22 of the first pipe. The probe 40 can be moved through the slide 10 and extend into the flow channel. When the probe 40 moves to a target point, the first electromagnet 31 is energized, attracting the slide 10 and applying a downward pressure to the slide 10 to form a sealed environment for measuring the target point, or measuring above or below the target point. When it is necessary to move the probe 40 to another target point, the first electromagnet 31 is de-energized, and the slide 10 can slide to the next position in the opening. The first electromagnet 31 is then energized again to complete the seal, and the probe 40 takes the measurement. This avoids the contradiction of using a fifth sealing ring to seal, which generates friction and prevents the slide 10 from moving. It is understood that the material of the slide 10 is a ferromagnetic material that can be attracted by the electromagnet, which is not specifically limited in some embodiments.

[0050] See also Figure 6-Figure 9 As shown, the skateboard 10 includes a first cover plate 11 and a second cover plate 12, and the first end face 112 of the first cover plate 11 cooperates with the second end face 122 of the second cover plate 12; the upper section of the first end face 112 is provided with a protrusion 113 having a first cavity 1132, and the lower end face of the protrusion 113 is a second inclined surface 1131; the upper section of the second end face 122 is provided with a first recessed portion having a second cavity 1222 that cooperates with the protrusion 113, the first recessed portion has a third inclined surface 1221 that cooperates with the second inclined surface 1131, and the first cavity 1132 cooperates with the second cavity 1222 to form a dark box for accommodating the probe 40; the fourth inclined surface of the first recessed portion and the lower section of the second end face 122, or the third inclined surface 1221 of the protrusion 113 and the lower section of the first end face 112 are provided with a second groove 1224 for placing the sixth sealing ring.

[0051] In order to minimize the influence of the gap formed by the probe 40 on the slide 10 on the measurement, the slide 10 is composed of a first cover plate 11 and a second cover plate 12 that can be connected and separated. A dark box is provided at the connection position of the first cover plate 11 and the second cover plate 12 to accommodate the bent part of the probe 40, that is, the detection part. In addition to considering the provision of the dark box on the first cover plate 11 and the second cover plate 12, the sealing performance of the connection between the two must also be considered. A protrusion 113 is provided on the upper section of the first end face 112 of the first cover plate 11, that is, the part close to the upper surface of the first cover plate 11. The lower end face of the protrusion 113 is a second inclined surface 1131. The second inclined surface 1131 is inclined upward from the first cover plate 11 to the second cover plate 12. Correspondingly, a first recessed portion that cooperates with the protrusion 113 is provided on the second cover plate 12. The first recessed portion has a third inclined surface 1221 that cooperates with the second inclined surface 1131. A second groove 1224 is provided around the surface where the first recessed portion and the raised portion 113 mate, for accommodating a sixth sealing ring. When sealing is required, the raised portion 113 of the first cover plate 11 is pressed against the first recessed portion of the second cover plate 12. It will be appreciated that a second groove 1224 is also provided at the portion where the second end surface 122 of the second cover plate 12 connects to the first end surface 112 of the first cover plate 11, for accommodating the sixth sealing ring.

[0052] Although not shown in the figures, it is understood that a sixth sealing ring may also be provided at the connection between the first cover plate 11 and the second cover plate 12. A groove may be provided on the first end surface 112 of the first cover plate 11 and the raised portion 113 for receiving the sixth sealing ring. Specifically, a groove may be provided at the second inclined surface 1131 of the raised portion 113 and the lower section of the first end surface 112. The lower section of the first end surface 112 refers to the portion below the lower edge of the raised portion 113. Similarly, the lower section of the second end surface 122 refers to the portion below the lower edge of the first recessed portion.

[0053] The inclined surfaces A111 on both sides of the first cover plate 11 and the inclined surfaces B121 on both sides of the second cover plate 12 are used to cooperate with the first inclined surfaces of the side end surfaces 211 of the corresponding first pipes to form slideways.

[0054] Furthermore, a first cavity 1132 is provided in the raised portion 113 , and a second cavity 1222 is provided in the lower portion of the first recessed portion. When the raised portion 113 is combined with the first recessed portion, the first cavity 1132 and the second cavity 1222 together form a dark box for accommodating the probe 40 .

[0055] It is understood that the upper surface of the protrusion 113 can be flush with the upper surface of the first cover plate 11, or can be higher than the upper surface of the first cover plate 11 to form a boss 114. Figure 8 or Figure 10 shown.

[0056] Considering the curved structure of the detection portion of probe 40, when it is stored in the dark box from the flow channel, a certain gap is separated between the two cover plates. Therefore, the second through hole 1223 provided in the second cover plate 12 for the passage of probe 40 should have a notch. Specifically, the upper end surface of the aforementioned raised portion 113 has a first through hole 1133 for the passage of probe 40. The bottom surface 1225 of the first recessed portion has a second through hole 1223 for the passage of probe 40 at a position corresponding to the first through hole 1133. The second end surface 122 also has a notch for the translation of probe 40 out of the second end surface 122, and the notch is connected to the second through hole 1223. It is understood that the inner sidewall of the second through hole 1223 also has a portion of the second groove 1224 for accommodating the sixth sealing ring.

[0057] During actual operation, the two cover plates are separated by a certain gap, the probe 40 is separated from the first recessed portion of the second end surface 122, and the probe 40 is lifted up to pass through the gap between the two cover plates and enter the dark box, and the two cover plates are then combined together.

[0058] In some embodiments, in order to ensure the sealing connection between the first cover plate 11 and the second cover plate 12, a pressure device is also required to be provided, which is used to press the connection part between the first cover plate 11 and the second cover plate 12 to achieve better sealing.

[0059] In an optional embodiment, the pressure-applying device includes a second electromagnet 32 ​​disposed on the first cover plate 11, and a connecting end plate 123 disposed on the second cover plate 12 opposite the second electromagnet 32. The second electromagnet 32 ​​engages the connecting end plate 123, causing the protrusion 113 to be pressed against the first recess. It is understood that the end plate 123 is made of a ferromagnetic material and is vertically connected to the upper surface of the second cover plate 12. The second electromagnet 32 ​​is disposed on the upper surface of the first cover plate 11, with its engaging surface opposite the second cover plate 12. When the two cover plates need to be connected, the second electromagnet 32 ​​is energized, and the two cover plates are pulled together by magnetic force, achieving good sealing at the portion where the two cover plates are connected.

[0060] In some embodiments, the pressure-applying device includes a first linear motion mechanism that drives relative motion between the first cover plate 11 and the second cover plate 12. The first linear motion mechanism includes a fixed portion 501 and a telescopic portion 502. The fixed portion 501 is located on the second cover plate 12, and the telescopic portion 502 is connected to the first cover plate 11. When the telescopic portion 502 extends, a gap is formed between the first end surface 112 and the second end surface 122, allowing the probe 40 to pass through. When the telescopic portion 502 shortens, the raised portion 113 presses against the first recessed portion. This pressure-applying device not only provides a tensile force between the two cover plates, improving sealing, but also automatically separates the two cover plates.

[0061] Specifically, the first linear motion mechanism includes a fixed portion 501 and a telescopic portion 502. The fixed portion 501 is disposed on the second cover plate 12 and provides power to the telescopic portion 502. The end of the telescopic portion 502 is connected to the first cover plate 11 and optionally to the boss 114 of the first cover plate 11. When the two cover plates need to be separated by a certain gap, the telescopic portion 502 extends, forming a gap between the two cover plates for the probe 40 to pass through, thereby accommodating or extending the aforementioned dark box. When the two cover plates need to be sealed together, the telescopic portion 502 shortens, and the boss 113 presses against the first recessed portion, which not only provides relative movement between the two cover plates but also provides a tensile force between the two cover plates, thereby improving the sealing performance.

[0062] It can be understood that the above-mentioned second electromagnet and cover plate attraction device, and the first linear motion mechanism can be set at the same time. When the two are set at the same time, the end plate 123 is detachably provided on the second cover plate 12 through a connecting piece. Optionally, a triangular connecting plate is connected to the opposite sides of the end plate 123, and the other end of the connecting plate is connected to the second cover plate 12. The end plate 123 extends over the boss 114 and is located above the first cover plate 11, that is, between the second electromagnet 32 ​​and the boss 114.

[0063] Illustratively, the first linear motion mechanism may be one of a linear motor, a hydraulic cylinder, and a pneumatic cylinder.

[0064] In some embodiments, the measuring device also includes a second linear motion mechanism 60 for driving the first cover plate 11 to slide, and a third linear motion mechanism 70 provided on the first cover plate 11; when the measuring device is in the first mode, the second linear motion mechanism 60 is used to drive the probe 40 to move in the first direction in the flow channel, and the third linear motion mechanism 70 is used to drive the probe 40 to move in the second direction; when the measuring device is in the second mode, the second linear motion mechanism 60 is used to seal the non-porous part of the first cover plate 11 or the second cover plate 12 on the opening, and the third linear motion mechanism 70 retracts the probe 40 into the dark box; the second linear motion mechanism 60 and the third linear motion mechanism 70 both include one of a linear motor, a hydraulic cylinder, a pneumatic cylinder or a ball screw.

[0065] See also Figure 3-Figure 4As shown, the second linear motion mechanism 60 is used to control the reciprocating motion of the first cover plate 11 in the horizontal direction, and the third linear motion mechanism 70 is used to control the movement of the probe 40 in the vertical direction, thereby realizing the automated control of the two-dimensional measurement of the probe 40 at the first pipe section. When the measuring device is in the first mode, that is, the measurement mode, the second linear motion mechanism 60 drives the probe 40 to move horizontally in the flow channel, and the third linear motion mechanism 70 is used to drive the probe 40 to move in the vertical direction. When the measuring device is in the second mode, that is, after the probe completes the measurement of the entire cross-section, the first linear motion mechanism separates the two cover plates by a certain gap, the third linear motion mechanism 70 retracts the probe 40 into the dark box, and the second linear motion mechanism 60 seals the non-porous part of the first cover plate 11 or the second cover plate 12 on the opening to form a complete first pipe inner wall.

[0066] Specifically, the second linear motion mechanism 60 and the third linear motion mechanism 70 each comprise a linear motor, a hydraulic cylinder, a pneumatic cylinder, or a ball screw. The third linear motion mechanism 70 is vertically positioned above the boss 114. When the third linear motion mechanism 70 includes a slideway, a clamp is provided on the slideway to clamp the upper portion of the probe 40. The slideway can be the nut portion of a ball screw, and the motor drives the screw to further control the movement of the slideway. Similarly, the linear motion mechanism 70 also comprises a ball screw device, with its slideway fixedly connected to the slideway of the third linear motion mechanism, thereby controlling the movement of the first cover plate 11.

[0067] In some embodiments, the above-mentioned measuring device also includes a controller. In a first mode, the controller is used to control the second electromagnet 32 ​​to engage with the end plate 123, or control the first linear motion mechanism to press the protrusion 113 onto the first recessed portion, the first electromagnet 31 is disconnected, and the probe 40 moves horizontally in the flow channel; in a second mode, the controller is used to control the second electromagnet 32 ​​to disconnect from the end plate 123, or control the first linear motion mechanism to separate the protrusion 113 from the first recessed portion, control the third linear motion mechanism 70 to retract the probe 40 into the dark box, the first electromagnet 31 is disconnected, and the second linear motion mechanism 60 seals the non-porous part of the first cover plate 11 or the second cover plate 12 on the opening.

[0068] Specifically, the controller is in communication with the first electromagnet 31, the second electromagnet 32, the first linear motion mechanism, the second linear motion mechanism 60, and the third linear motion mechanism 70. When in test mode, the controller energizes the second electromagnet 32, causing it to engage the end plate 123. The controller also controls the extension portion 502 of the first linear motion mechanism to shorten, providing a certain tensile strength between the two cover plates. After testing a target point, the first electromagnet 31 is deactivated, allowing the first cover plate 11 to move horizontally, thereby enabling the probe 40 to move horizontally within the flow channel.

[0069] After completing the two-dimensional measurement of a cross section, the controller is further configured to control the second electromagnet 32 ​​to be de-energized and disconnected from the end plate 123, control the first linear motion mechanism to separate the protrusion 113 from the first recessed portion by a certain gap, control the third linear motion mechanism 70 to retract the probe 40, control the first linear motion mechanism to press the protrusion 113 into the first recessed portion, and place the probe 40 in the dark box. The first electromagnet 31 is controlled to be disconnected, and the second linear motion mechanism 60 to seal the non-porous portion of the first cover plate 11 or the second cover plate 12 on the opening. The non-porous portion of the first cover plate 11 refers to the portion excluding the protrusion 113, and the non-porous portion of the second cover plate 12 refers to the portion excluding the second through hole 1223 of the first recessed portion, that is, the second through hole 1223 is moved out of the first pipe opening.

[0070] See also Figure 10 As shown, in some embodiments, the above-mentioned measuring device also includes a sealing device for sealing the first through hole 1133, and the sealing device includes a clip 90 and a sealing ring 91. The sealing ring 91 is mounted on the probe 40, and the clip 90 has a hole for embedding the sealing ring 91. The clip 90 is connected to the first cover plate 11 by an adjusting bolt. The clip 90 seals the sealing ring, the first through hole 1133 and the probe 40, and the height of the sealing ring 91 is greater than the depth of the hole of the clip 90.

[0071] Specifically, the sealing ring 91 is sleeved on the probe 40 and the clip 90 of the probe 40. The clip 90 is located above the sealing ring 91. A plurality of adjustment bolts are provided around the clip 90. When the first through hole 1133 needs to be sealed, the plurality of adjustment bolts are tightened around the first through hole 1133 to press the clip 90 against the elastic sealing ring 91, thereby achieving a seal between the sealing ring 91, the first through hole 1133, and the probe 40. By adjusting the pre-tightening force of the bolts, the probe 40 can be moved up and down in the first through hole 1133.

[0072] In an optional embodiment, the clip 90 has a stepped hole, and the sealing ring 91 is arranged in the stepped hole. A portion of the sealing ring 91 extends out of the bottom of the clip 90, thereby limiting the sealing ring 91 and achieving a better sealing effect.

[0073] In some embodiments, the outer diameter of the sealing ring 91 is 9 mm, which is the same as the inner diameter of the stepped hole of the clip 90, and the inner diameter of the sealing ring 91 is 4 mm, which is the same as the outer diameter of the probe 40. The probe 40 may be a pitot tube.

[0074] In some embodiments, the first pipe 20 is further provided with two slide grooves 80 for supporting the slide plate on the outer side of the electromagnet. When the first cover plate 11 and the second cover plate 12 move, they can slide in the corresponding slide grooves 80 .

[0075] In some embodiments, L-shaped limit blocks are further provided on the outside of the two side end surfaces 211 of the opening of the first pipe 20, wherein the upper end surface of the L-shaped limit block is provided above the edge of the slide 10 and does not contact the slide 10. The limit block is used to prevent the slide from tipping over or falling off.

[0076] When performing acoustic measurements in high-flow, high-pressure differential environments, the large pressure difference between the inside and outside of the second pipe creates a suction force on the microphone itself, pushing it toward the interior of the second pipe. To prevent the microphone from being sucked into the second pipe, the microphone mount must exert sufficient force on the microphone. Furthermore, the microphone is frequently disassembled and assembled during experiments, and repeated disassembly can cause irreversible damage to the microphone's power cord connection. Furthermore, the microphone must be easily disassembled and assembled, ensuring ease of positioning and securing.

[0077] See also Figures 11 to 12 As shown, an embodiment of the present invention provides an acoustic liner measurement device, comprising a second pipe 910, a microphone 924, a casing 930, and an acoustic liner disposed between the second pipe 910 and the casing 930. The end surface of the perforated plate of the acoustic liner is flush with the inner wall of the third wall 911 of the second pipe 910. The microphone 924 is disposed on a second wall 912 of the second pipe 910 opposite the third wall 911, and the receiving end of the microphone 924 is flush with the inner wall of the second wall 912. At least one microphone 924 is detachably mounted on the second wall 912 via a mounting base 920. The mounting base 920 includes a first fixture 921 and a second fixture 922 disposed on the second wall 912. Both the first fixture 921 and the second fixture 922 have cavities for the microphone 924 to pass through. The first fixture 921 is used to clamp the microphone 924 and is detachably connected to the second fixture 922.

[0078] Specifically, the second pipe 910 has a third wall 911 and a second wall 912 disposed opposite each other. A microphone 924 is detachably mounted on the second wall 912 via a mounting base 920. It is understood that there may be one microphone 924, or multiple microphones 924 may be disposed along the airflow direction of the second pipe 910. The opening of the casing 930 communicates with the opening of the second wall 912 of the second pipe 910. An acoustic liner is disposed between the opening of the casing 930 and the opening of the third wall 911 of the second pipe 910. The upper surface of the perforated plate of the acoustic liner is flush with the inner wall of the second wall 912, while the lower end surface of the microphone 924 is flush with the inner wall of the second wall 912. This prevents any interference with the airflow in the second pipe 910, thereby ensuring accurate measurement results.

[0079] For example, mounting base 920 includes a first fixture 921 and a second fixture 922. Second fixture 922 is detachably mounted on second wall 912, while first fixture 921 is detachably mounted on second fixture 922. Both first fixture 921 and second fixture 922 have cavities for passage of microphone 924. Because the lower end of microphone 924 is larger than the rest of the body, only one fixture is used to mount it on the second pipe. This fixture also holds microphone 924, making it impossible to remove microphone 924 without removing the fixture. However, if the fixture is removed, prolonged disassembly and assembly can compromise the seal between second pipe 910 and mounting base 920. Therefore, the embodiment of the present invention adopts the method of a first tooling 921 and a second tooling 922, wherein the first tooling 921 clamps the microphone 924, and the combination of the first tooling 921 and the microphone 924 can be disassembled from the second tooling 922. After the second tooling 922 and the second pipe 910 are installed, they are basically not disassembled again, thereby protecting the sealing between the second pipe 910 and the mounting seat 920 from being damaged.

[0080] Considering that when acoustic measurements are performed in an environment with high flow rate and high pressure difference, the internal pressure of the second pipe is much lower than the atmospheric pressure, and when the microphone is working, its static pressure hole needs to be connected to the inside of the second pipe, which puts forward sealing requirements for the microphone mounting base. Figure 20 As shown, sealing rings are provided at the connection between microphone 924 and first fixture 921, at the connection between first fixture 921 and second fixture 922, and at the connection between second fixture 922 and second wall 912. The static pressure hole 9241 of microphone 924 is located below the connection between microphone 924 and first fixture 921, so that the static pressure hole 9241 is connected to the interior of the second pipe through the cavities of the first fixture 921 and second fixture 922. Furthermore, sealing rings are provided at the connection between first fixture 921 and second fixture 922, and at the connection between second fixture 922 and second wall 912. This ensures that the static pressure hole 9241 is connected to the interior of the second pipe 910 and is not affected by atmospheric pressure, allowing the microphone 924 to function properly.

[0081] In order to ensure the clamping force on the microphone 924, prevent the microphone 924 from being sucked into the second pipe 910 due to the pressure difference between the inside and the outside, and to facilitate the removal and assembly of the microphone 924 on the first tooling 921, the embodiment of the present invention adopts a clamping method. Figures 2 to 14As shown, the first tooling 921 has a clamping portion, which includes a clamping hoop 923 and a plurality of petal-shaped contraction portions 9211 arranged at intervals along the circumference of the first tooling 921. The clamping hoop 923 is sleeved on the contraction portion 9211, and the contraction portion 9211 clamps the microphone 924 under the action of the clamping hoop 923; the cavity of the first tooling 921 is provided with a first groove 9213 near the contraction portion 9211 to accommodate a first sealing ring 941. The first sealing ring 941 is used to seal the first tooling 921 and the microphone 924.

[0082] When microphone 924 is assembled on first fixture 921, it passes through the cavity of first fixture 921 and the first sealing ring 941 located in first groove 9213. After positioning, clamp 923 is tightened. Under the action of clamp 923, multiple petal-shaped contractions 9211 arranged circumferentially on first fixture 921 clamp microphone 924. The static pressure port 9241 of microphone 924 is located in the cavity below the first sealing ring 941, ensuring that the static pressure port 9241 is connected to the interior of second pipe 910 and is not affected by atmospheric pressure. To remove microphone 924 from first fixture 921, simply loosen clamp 923. Therefore, the use of a clamp not only provides sufficient clamping force but also facilitates assembly and disassembly.

[0083] Considering that the lower end surface of the microphone 924 needs to be flush with the inner wall surface of the second wall surface 912, the height of the microphone 924 needs to be adjusted, so the heights of the first fixture 921 and the second fixture 922 should have known heights. In order to ensure that the heights of the first fixture 921 and the second fixture 922 are constant, for example, refer to Figure 15-16 As shown, the cavity of the second tooling 922 has a first step surface 9222, the second wall surface 912 and the second tooling 922 have a second step surface 9121 at the connection position, the third end surface 9214 of the first tooling 921 facing away from the clamping portion abuts against the first step surface 9222, and the fourth end surface 9223 of the second tooling 922 facing away from the first tooling 921 abuts against the second step surface 9121.

[0084] Specifically, when the first fixture 921 is connected to the second fixture 922, the third end face 9214 of the first fixture 921 abuts against the first step face 9222. The first step face 9222 may be part of the second groove 9221, wherein the second groove 9221 is used to accommodate the fourth sealing ring 944 for sealingly connecting the first fixture 921 to the second fixture 922. The first step face 9222 is used to limit the position of the first fixture 921. Similarly, a second step face 9121 is provided at the connection position between the second wall 912 and the second fixture 922. When the second fixture 922 is connected to the second wall 912, the second step face 9121 is provided within the through hole of the second wall 912, so that the fourth end face 9223 of the second fixture 922 abuts against the second step face 9121. When the first fixture 921 and the second fixture 922 are connected, the height of the entire mounting base 920 is fixed. At this time, based on the known length of the microphone 924, the microphone 924 can be fixed before the mounting base is installed so that its lower end surface is flush with the inner wall of the second wall 912 after being installed in the second pipe 910.

[0085] In some embodiments, as Figure 14-16 As shown, the first fixture 921 is screwed to the second fixture 922; the second fixture 922 is screwed to the second wall 912. For example, the first fixture 921 has an external thread, and the second fixture 922 has a corresponding internal thread, and the first fixture 921 can be connected to the second fixture 922 by threading. Similarly, the through hole in the second wall 912 has an internal thread, and the other end of the second fixture 922 has an external thread, and the second fixture 922 can be connected to the second wall 912 by threading. The first fixture 921 and the second fixture 922, as well as the second fixture 922 and the second wall 912, can also be connected by a snap-fit ​​method. For example, the first fixture 921 has an elastic snap, and one end of the second fixture 922 has a slot in its cavity suitable for snap-fit ​​connection; similarly, the other end of the second fixture 922 has an elastic snap, and the through hole in the second wall 912 has a slot suitable for snap-fit ​​connection.

[0086] Since the microphone head is threadedly connected to the wire, in order to prevent excessive rotation of the microphone 924 interface when the first fixture 921 and the microphone 924 are screwed into the second fixture 922 as a whole, and because the first fixture 921 and the microphone 924 are frequently disassembled and assembled as a whole during use, for example, when the first fixture 921 and the second fixture 922 are threaded together, the first fixture 921 has an external thread section 9212 with 1-4 coarse threads. The coarse threads are designed to ensure that the first fixture 921 has sufficient force to apply to the first sealing ring 941 and to minimize the number of threads. This application uses 1-4 threads, with 1.5 or 2.5 threads being optional.

[0087] See also Figure 15-16 As shown, in order to ensure the sealing between the second tooling 922 and the second wall surface 912, as well as the installation height of the second tooling 922, the second tooling 922 has a connecting section 9225 connected to the second wall surface 912, the length of the connecting section 9225 is a, and the distance between the second step surface 9121 and the outer surface of the second wall surface 912 is b, wherein a>b; the above-mentioned distance a>b ensures that when the second tooling 922 is installed on the second wall surface 912, the fourth end surface 9223 of the second tooling 922 can be abutted against the second step surface 9121.

[0088] For example, the second fixture 922 has a third stepped surface 9224 near the connecting section 9225. The connecting section 9225 between the third stepped surface 9224 and the outer surface of the second wall 912 is fitted with a second sealing ring 942. The second sealing ring 942 is used to seal between the second fixture 922 and the second wall 912. Specifically, the second sealing ring 942 is fitted over the connecting section 9225. When the second fixture 922 is connected to the second wall 912, the second sealing ring 942 is pressed against the outer surface of the second wall 912 by the third stepped surface 9224, thereby achieving a seal between the two and ensuring the accuracy of the acoustic lining measurement results.

[0089] Considering the installation of the acoustic liner and the significant pressure differential between the inside and outside of the casing in high-flow environments, a leak could cause deviations in the measurement results. For example, the casing 930 is integrally molded to ensure the casing's tightness. The casing 930 is detachably connected to the second pipe 910, for example, using bolts. The casing 930 includes a cavity for accommodating the acoustic liner. The cavity includes a bottom plate 931 that abuts the end face of the acoustic liner facing away from the perforated plate. The position of the bottom plate 931 within the casing 930 is adjustable, and the bottom plate 931 is used to seal the acoustic liner within the casing 930. The use of the adjustable bottom plate 931 abutting the end face of the acoustic liner facing away from the perforated plate eliminates any excess gaps between the acoustic liner and the casing, or in other words, provides a tight seal within the casing, thereby preventing a pressure differential between the casing and the second pipe. Since the acoustic liner is a noise reduction element used in multiple scenarios, its type and height are not fixed, while the depth of the processed casing is fixed. Therefore, the use of an adjustable bottom plate 931 can be suitable for acoustic liners of different heights and ensure the sealing of the acoustic liner in the casing.

[0090] Specifically, one or more adjusting devices 932 for adjusting the bottom plate 931 are provided in the cavity of the casing 930. Figure 17As shown, adjustment device 932 is disposed between base plate 931 and third wall 934. Third wall 934 is the bottom surface of casing 930 opposite base plate 931. Adjustment device 932 includes a screw sleeve 9322 and a stud 9321. The relative movement of stud 9321 and screw sleeve 9322 causes base plate 931 to abut the end surface of the acoustic liner facing away from the perforated plate. Stud 9321 is rotatably mounted on third wall 934, while screw sleeve 9322 is mounted on base plate 931. By adjusting stud 9321, the position of base plate 931 in the casing is adjusted so that base plate 931 abuts the bottom surface of the acoustic liner to be tested. It is understood that stud 9321 can be disposed on base plate 931, while screw sleeve 9322 is disposed on third wall 934, so that the height of base plate 931 can also be adjusted.

[0091] In order to ensure the sealing between the casing 930 and the second pipe 910, and the outer surface of the perforated plate of the acoustic liner is flush with the inner surface of the third wall 911, please refer to Figure 18-19 As shown, in this embodiment of the present invention, a lug 933 protruding from the casing 930 is provided at the connection point between the casing 930 and the second pipe 910. The second pipe 910 has a second recess 913 that mates with the lug 933. A third sealing ring is provided on the wall of the second recess 913, which provides a seal between the casing 930 and the second pipe 910. The perforated plate of the acoustic liner is slightly larger than the rest of the liner, fitting neatly over the upper surfaces of the two lugs 933 protruding from the casing 930. By engaging with the second recess 913 of the second pipe 910, the acoustic liner is pressed against the lugs 933, ensuring that the upper surface of the acoustic liner and the lower surface of the second pipe are flush. It should be understood that while two lugs 933 are shown in the figure, in some embodiments, four lugs 933 may be provided around the opening of the casing. Furthermore, a groove is provided on the wall surface of the second recessed portion 913 of the second pipe 910 for placing a third sealing ring, thereby ensuring sealing between the casing 930 and the second pipe 910 after the acoustic liner is placed.

[0092] During the specific acoustic measurement, the first sealing ring 941 is installed in the first groove 9213 of the first tooling 921, the microphone 924 passes through the first tooling 921, and the clamp 923 is put on the contraction part 9211 and pre-tightened to form a first assembly;

[0093] Install the second sealing ring 942 on the second groove 9221 of the second tooling 922, and install the first assembly on the second tooling 922;

[0094] The fourth sealing ring 944 is placed on the connecting section 9225 of the second fixture 922 and then installed in the through hole of the second wall 912. The relative height of the microphone 924 and the first fixture 921 is adjusted. Finally, the clamp 923 is tightened to clamp the microphone 924. This allows the lower end surface of the microphone 924 to be flush with the inner surface of the second wall 912. This is because the height of the first fixture 921 and the second fixture 922 is fixed.

[0095] Then, according to the height of the acoustic liner, the bottom plate 931 inside the casing is adjusted in height by the adjusting device 932 so that it abuts against the bottom surface of the acoustic liner.

[0096] After the test is completed, if the microphone 924 needs to be removed or replaced, only the first tooling 921 and the microphone 924 clamped therein need to be removed, and then the clamp can be loosened. The second tooling 922 does not need to be frequently disassembled.

[0097] The embodiment of the present invention further provides a flow tube measurement method, comprising the measurement device in the above technical solution. The flow tube measurement method comprises the following steps:

[0098] Step 1: The first and second electromagnets 31 and 32 are energized, the two cover plates are pressed against the opening of the first pipe 20, and the third linear motion mechanism drives the probe 40 to measure the flow parameters of the first target point; the above flow parameters include total temperature, total pressure, static temperature, velocity field, velocity vector, boundary layer information, flow particle field, spatial distribution of sound pressure, etc., and other physical quantities are calculated from them.

[0099] Step 2: The first electromagnet 31 is de-energized and the second electromagnet 32 ​​is energized. The second linear motion mechanism 60 drives the first cover plate 11 and the second cover plate 12 to move in a direction perpendicular to the length of the first pipe 20, driving the probe 40 on the first cover plate 11 to the second target point. The first electromagnet 31 is energized, and the two cover plates are pressed against the opening of the first pipe 20. The probe 40 measures the flow parameters at the second target point.

[0100] Step 3: Repeat steps 1 and 2 above. After all target points on the cross section of the first pipe 20 are measured, the first electromagnet 31 is de-energized, and the first linear motion mechanism drives the first cover plate 11 and the second cover plate 12 to separate by a certain gap to allow the probe 40 to retract from the flow channel. The third linear motion mechanism 70 retracts the probe 40 into the dark box, and the first linear motion mechanism drives the first cover plate 11 and the second cover plate 12 to engage with each other, eliminating the gap between them.

[0101] Step 4: The first electromagnet 31 is powered off, and the second linear motion mechanism 60 moves the first cover plate 11 and the second cover plate 12 as a whole, so that the second through hole left by the probe 40 is moved to the outside of the first pipe opening, and the non-porous parts of the two covers are sealed on the opening, forming a complete flow channel wall surface on the inner wall of the first pipe 20, thereby avoiding the influence of the second through hole on the flow field.

[0102] Before step 1 above, you may also include:

[0103] Step 10: Install the first sealing ring 941 in the first groove 9213 of the first tooling 921 , pass the microphone 924 through the first tooling 921 , and put the clamp 923 on the contraction portion 9211 and pre-tighten it to form a first assembly;

[0104] Step 11: Install the second sealing ring 942 on the second groove 9221 of the second tooling 922, and install the first assembly on the second tooling 922;

[0105] Step 12: Slide the fourth sealing ring 944 onto the connecting section 9225 of the second fixture 922 and then install it in the through hole of the second wall 912. Adjust the relative height of the microphone 924 and the first fixture 921. Finally, tighten the clamp 923 to clamp the microphone 924 so that the lower end surface of the microphone 924 is flush with the inner surface of the second wall 912.

[0106] Step 13: The adjusting device 932 adjusts the height of the bottom plate 931 inside the casing so that it abuts against the bottom surface of the acoustic liner, thereby forming a seal with the acoustic liner.

[0107] After step 4 above, the following steps may also be included:

[0108] Step 5: Monitor the sound transmission mode and noise reduction of the acoustic lining through the microphone 924 installed on the second wall 912.

[0109] It is understandable that, in the above acoustic measurement step, the microphones 924 may be arranged as a microphone array that matches the corresponding extraction method, so as to achieve accurate measurement of the acoustic impedance of the acoustic liner within a sufficiently wide frequency band.

[0110] In actual measurement, Figure 1Or as shown in 2, first, the flow measurement unit is sealed by controlling the on and off power of the electromagnet in the flow measurement device, and the displacement movement mechanism moves the probe in the vertical and horizontal directions, thereby realizing the flow parameter measurement of the entire two-dimensional cross-section of the first pipeline. After the measurement of the entire cross-section is completed, the displacement mechanism of the probe retracts the probe into the dark box. In order to eliminate the influence of the probe and the hole of the probe on the inner wall of the first pipeline on the fluid, the displacement mechanism of the probe moves the first cover plate and the second cover plate as a whole, and seals the non-porous part of the cover plate on the opening, so that the inner wall of the first pipeline forms a complete flow channel wall surface. After that, the fluid flow in the second pipeline in the acoustic measurement unit will be more uniform, and no additional noise will be generated. When the acoustic lining measurement device performs acoustic measurement again, the measurement result will be closer to the actual situation.

[0111] The flow tube test bench in this embodiment combines a high-speed flow tube with a two-dimensional measurement mechanism, resolving the sealing issue associated with high flow rates. The entire device not only allows modular assembly, enabling measurement of sound transmission modes and noise reduction under various sound source conditions, but also completely eliminates the influence of the fluid measurement probe on the flow channel, enabling subsequent precise acoustic measurements in the flow tube.

[0112] In the description of this specification, the description with reference to the terms "one embodiment / method", "some embodiments / methods", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment / method or example are included in at least one embodiment / method or example of the present application. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment / method or example. Moreover, the specific features, structures, materials or characteristics described may be combined in an appropriate manner in any one or more embodiments / methods or examples. In addition, those skilled in the art may combine and combine different embodiments / methods or examples described in this specification and the features of different embodiments / methods or examples, unless they are contradictory.

[0113] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of such features. Throughout the description of this application, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0114] Those skilled in the art will appreciate that the above embodiments are merely intended to clearly illustrate the present disclosure and are not intended to limit the scope of the present disclosure. Other changes or modifications may be made based on the above disclosure, and such changes or modifications are still within the scope of the present disclosure.

Claims

1. A flow tube test bench, characterized in that: The flow tube test bench is used for acoustic experiments of a flow channel with a wide velocity range. The flow tube test bench includes a flow measurement unit, an acoustic measurement unit, and a sound source unit. The flow measurement unit, the acoustic measurement unit, and the sound source unit are detachably connected. The flow measurement unit includes a first pipe and a flow channel measurement device provided in the first pipe, wherein the flow channel measurement device is used for flow measurement at a two-dimensional cross section of the first pipe; The acoustic measurement unit includes a second pipe and an acoustic liner measuring device provided in the second pipe, wherein the acoustic liner measuring device is used for acoustic measurement of the acoustic liner; The sound source unit includes at least one third pipe and a sound source device provided in the third pipe, wherein the sound source device is used to generate a broadband sound source; The flow channel measuring device includes a probe and a slide. The first wall of the first pipe has an opening. The opening forms two side end surfaces on the first wall. The side end surfaces are first inclined surfaces that reduce the diameter of the opening from the outside to the inside. The opening forms bottom end surfaces on the two side walls of the first pipe, respectively. The bottom end surfaces are flush with the inner wall of the first wall. The two side end surfaces and the two bottom end surfaces are each provided with a first groove for accommodating a fifth sealing ring. The slide is coordinated with the opening to form a closed flow channel of the first pipe. The slide has an inclined surface that matches the first inclined surface. The slide is slidably disposed in the opening. The probe is movably passed through the slide and extends into the flow channel. A force applying device is provided on the outer side of at least one of the side walls, and the force applying device is used to press the slide plate against the opening; The slide plate includes a first cover plate and a second cover plate, wherein a first end surface of the first cover plate is matched with a second end surface of the second cover plate; The upper section of the first end surface is provided with a raised portion having a first cavity, and the lower end surface of the raised portion is a second inclined surface; The upper section of the second end surface is provided with a first recessed portion having a second cavity that cooperates with the protrusion, the first recessed portion has a third inclined surface that cooperates with the second inclined surface, and the first cavity and the second cavity cooperate to form a dark box for accommodating the probe; The third inclined surface of the first recessed portion and the lower section of the second end surface, or the second inclined surface of the raised portion and the lower section of the first end surface are provided with a second groove for accommodating a sixth sealing ring.

2. The test bench according to claim 1, characterized in that The first pipeline, the second pipeline and the third pipeline are connected by flanges, and the two connected flanges are positioned by positioning pins, and the positioning pins are used to make the inner wall surfaces of the pipelines flush.

3. The test bench according to claim 1, characterized in that The flow measurement unit further includes a sealed shell arranged outside the flow channel measurement device, and the shell is used to seal the flow channel measurement device.

4. The test bench according to claim 1, characterized in that The upper end surface of the protrusion has a first through hole for the probe to pass through, the lower end surface of the first recess has a second through hole for the probe to pass through at a position corresponding to the first through hole, and the second end surface also has a notch for the probe to translate, and the notch is connected to the second through hole.

5. The test bench according to claim 4, characterized in that: The measuring device further includes a pressing device for pressing a connection portion between the first cover plate and the second cover plate.

6. The test bench according to claim 5, characterized in that: The pressure device includes a second electromagnet arranged on the first cover plate and a connecting end plate arranged on the second cover plate opposite to the second electromagnet. The second electromagnet attracts the connecting end plate so that the protrusion is pressed against the first recess.

7. The test bench according to claim 6, characterized in that The pressure applying device includes a first linear motion mechanism that drives the first cover plate and the second cover plate to move relative to each other; The first linear motion mechanism includes a fixed part and a telescopic part. The fixed part is provided on the second cover plate, and the telescopic part is connected to the first cover plate. When the telescopic part is extended, a gap for the probe to pass through is formed between the first end face and the second end face; when the telescopic part is shortened, the protrusion is pressed against the first recessed part.

8. The test bench according to claim 7, characterized in that: The first linear motion mechanism includes one of a linear motor, a hydraulic cylinder, and a pneumatic cylinder.

9. The test bench according to claim 7, characterized in that: The measuring device further includes a second linear motion mechanism for driving the first cover plate to slide, and a third linear motion mechanism provided on the first cover plate; When the measuring device is in the first mode, the second linear motion mechanism is used to drive the probe to move in the first direction in the flow channel, and the third linear motion mechanism is used to drive the probe to move in the second direction; When the measuring device is in the second mode, the third linear motion mechanism retracts the probe into the dark box, and the second linear motion mechanism is used to seal the non-porous portion of the first cover plate or the second cover plate on the opening; The second linear motion mechanism and the third linear motion mechanism each include one of a linear motor, a hydraulic cylinder, an air cylinder or a ball screw.

10. The test bench according to claim 9, characterized in that: The measuring device further includes a controller, the force applying device is a first electromagnet, and in the first mode, the controller is used to control the second electromagnet to engage with the end plate, or control the first linear motion mechanism to press the protrusion against the first recessed portion. When the first electromagnet is disconnected, the probe moves horizontally in the flow channel. In the second mode, the controller is used to control the second electromagnet to disconnect from the end plate, or control the first linear motion mechanism to separate the protrusion from the first recessed portion, control the third linear motion mechanism to retract the probe into the dark box, the first electromagnet is disconnected, and the second linear motion mechanism seals the non-porous part of the first cover plate or the second cover plate on the opening.

11. The test bench according to claim 9, characterized in that: The measuring device also includes a sealing device for sealing the first through hole, the sealing device includes a clip and a sealing ring, the sealing ring is sleeved on the probe, the clip has a hole for the sealing ring to be embedded, the clip is connected to the first cover plate by an adjusting bolt, the clip seals the sealing ring, the first through hole and the probe, and the height of the sealing ring is greater than the depth of the hole of the clip.

12. The test bench according to claim 10, characterized in that: There are two first electromagnets, which are respectively arranged on both sides of the first pipe; A sliding groove cooperating with the corresponding cover plate is further provided on the outer side of each electromagnet, and the cover plate is slidably arranged in the corresponding sliding groove.

13. The test bench according to claim 1, characterized in that: The acoustic liner measuring device includes a microphone, a casing, and an acoustic liner disposed between the second pipe and the casing, wherein the end surface of the perforated plate of the acoustic liner is flush with the inner wall of the first wall of the second pipe, the microphone is disposed on the second wall of the second pipe opposite to the first wall, and the receiving end of the microphone is flush with the inner wall of the second wall; At least one microphone is detachably mounted on the second wall surface via a mounting base. The mounting base includes a first tooling and a second tooling mounted on the second wall surface. Both the first tooling and the second tooling have cavities for the microphone to pass through. The first tooling is used to clamp the microphone. The first tooling is detachably connected to the second tooling.

14. The test bench according to claim 13, characterized in that: Sealing rings are provided at the connection position between the microphone and the first tooling, at the connection position between the first tooling and the second tooling, and at the connection position between the second tooling and the second wall surface.

15. The test bench according to claim 13, characterized in that: The first tool has a clamping portion, the clamping portion including a clamp and a plurality of petal-shaped contraction portions spaced apart along the circumference of the first tool, the clamp being sleeved on the contraction portion, and the contraction portion clamping the microphone under the action of the clamp; A first groove for accommodating a first sealing ring is provided in the cavity of the first tooling near the contraction portion. The first sealing ring is used for sealing the first tooling and the microphone.

16. The test bench according to claim 15, characterized in that: The cavity of the second tooling has a first step surface, the second wall surface has a second step surface at the connection position between the second tooling, the third end surface of the first tooling facing away from the clamping portion abuts on the first step surface, and the fourth end surface of the second tooling facing away from the first tooling abuts on the second step surface.

17. The test bench according to any one of claims 13 to 16, characterized in that: The first tooling is screwed or clamped to the second tooling; the second tooling is screwed or clamped to the second wall surface.

18. The test bench according to claim 17, characterized in that: When the first tooling is threadedly connected to the second tooling, the first tooling has an external thread segment, the number of thread turns of the external thread segment is 1-4, and the thread is coarse.

19. The test bench according to claim 17, characterized in that: The second tooling has a connecting section connected to the second wall surface, the length of the connecting section is a, and the distance between the second step surface and the outer surface of the second wall surface is b, where a>b; The second tooling has a third step surface near the connecting section, and the connecting section between the third step surface and the outer surface of the second wall is sleeved with a second sealing ring, which is used for sealing between the second tooling and the second wall.

20. The test bench according to claim 17, characterized in that The casing is detachably connected to the second pipe; The casing has a cavity for accommodating the acoustic liner. A bottom plate is provided in the cavity and abuts against the end face of the acoustic liner facing away from the perforated plate. The position of the bottom plate in the casing is adjustable and the bottom plate is used to seal the acoustic liner in the casing.

21. The test bench according to claim 20, characterized in that At least one adjustment device for adjusting the bottom plate is provided in the cavity of the casing. The casing has a third wall surface opposite to the bottom plate. The adjustment device is provided between the bottom plate and the third wall surface. The adjustment device includes a screw sleeve and a stud. The bottom plate is brought into contact with the end surface of the acoustic liner facing away from the perforated plate through the relative movement of the stud and the screw sleeve.

22. The test bench according to claim 20, characterized in that An ear plate protruding from the casing is provided at the connection position between the casing and the second pipe. The second pipe has a second recessed portion that cooperates with the ear plate. A third sealing ring is provided on the wall surface of the second recessed portion. The third sealing ring is used for sealing between the casing and the second pipe.

23. A flow tube measurement method, characterized in that: Applied to the test bench according to any one of claims 1 to 22, the measuring method comprises: The first electromagnet and the second electromagnet are energized, and the third linear motion mechanism drives the probe to measure the flow parameters of the first target point; The first electromagnet is powered off and the second electromagnet is powered on, the second linear motion mechanism drives the probe to the second target point, the first electromagnet is powered on, and the probe measures the flow parameters of the second target point; When the measurement of all target points is completed, the first electromagnet is powered off, the first linear motion mechanism drives the first cover plate and the second cover plate to separate, and the third linear motion mechanism retracts the probe into the dark box; The first electromagnet is powered off, and the second linear motion mechanism covers the non-porous portion of the first cover plate or the second cover plate on the opening.

24. The measurement method according to claim 23, characterized in that Also includes: An acoustic liner is placed between the second pipe and the casing, with the end face of the perforated plate of the acoustic liner flush with the inner wall of the first wall of the second pipe. The adjustment device is adjusted to place the bottom plate in contact with the end face of the acoustic liner facing away from the perforated plate. A microphone is mounted on the second wall through a mounting base, with the receiving end of the microphone flush with the inner wall of the second wall, and acoustic measurements are performed on the acoustic liner.

Images