CN115236177A - A kind of flow tube test bench and its testing method - Google Patents

Abstract

The invention provides a flow tube experiment table and a test method thereof, relates to the field of flow tube experiments, and aims to solve the technical problem that the flow velocity and acoustic parameters of a two-dimensional physical field are difficult to measure conveniently and accurately under the conditions of wide-speed-domain flow and wide-frequency sound sources. The flow tube experiment table comprises a flow measurement unit, an acoustic measurement unit and a sound source unit, wherein the flow measurement unit, the acoustic measurement unit and the sound source unit are detachably connected; the flow measuring unit comprises a first pipeline and a flow channel measuring device arranged on the first pipeline, and the flow channel measuring device is used for flow measurement at the position of a two-dimensional section of the first pipeline; the acoustic measurement unit comprises a second pipeline and an acoustic lining measurement device arranged on the second pipeline, and the acoustic lining measurement device is used for acoustic measurement of an acoustic lining; the sound source unit comprises at least one third pipeline and a sound source device arranged on the third pipeline, and the sound source device is used for generating a broadband sound source. The flow tube experiment table is used for the acoustic experiment of the flow channel of the wide-speed-domain flow.

Description

A kind of flow tube test bench and its testing method

technical field

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

Background technique

The flow tube test bench is an important equipment for the research of acoustic lining and extraction method. However, due to the problem of its own structure, it is difficult for domestic and foreign flow tube test benches to perform experiments with high flow rates exceeding Mach 0.2. Moreover, the flow tube test bench needs to take into account both flow velocity measurement and acoustic measurement. In the existing structure, the flow velocity measurement device will destroy the flow of air in the flow channel, resulting in inaccurate subsequent acoustic measurement results. At the same time, it is difficult to accurately measure the real flow velocity in the flow channel by measuring the flow velocity in the flow tube test bench in the prior art.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a flow tube test bench and a test method to solve the problem that it is difficult to conveniently and accurately measure the flow velocity and acoustic parameters of a two-dimensional physical field under the conditions of wide-speed domain flow and wide-frequency sound source.

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

An embodiment of the present invention provides a flow tube test bench, which is used for an acoustic experiment of a flow channel of a wide-speed domain flow. 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 pipeline and a flow channel measurement device provided in the first pipeline, the flow channel measurement device is used for flow measurement at a two-dimensional cross-section of the first pipeline;

The acoustic measurement unit includes a second pipe and an acoustic lining measurement device provided in the second pipe, the acoustic lining measurement device is used for acoustic measurement of the acoustic lining;

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.

Compared with the prior art, the flow tube test bench provided by the present invention can carry 0 to 0.99 Mach wide-speed domain flow and high-intensity sound environment, and it is sealed to avoid leakage flow caused by high internal and external pressure difference, and can realize accurate measurement of sound lining and broadband frequency. . The flow measurement unit of the present invention can conveniently measure the flow velocity of a two-dimensional physical field through a displacement mechanism. At the same time, the flow channel measurement device can realize the measurement of the two-dimensional cross-sectional flow velocity of the first pipeline, and then realize that the test device is moved out of the first pipeline to avoid affecting the fluid in the flow channel, thereby making the acoustic measurement result more accurate.

Another object of the present invention is to also provide a flow tube measurement method, applied to the above-mentioned experimental bench, and the measurement method comprises:

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

The first electromagnet is powered off, 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 parameter 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 recovers the probe to the cassette;

The first electromagnet is de-energized, and the second linear motion mechanism seals the non-porous portion of the first cover plate or the second cover plate on the opening.

Compared with the prior art, the measuring method of the present invention has the following advantages:

The flow tube measurement method has the same advantages as the above-mentioned flow channel test bench relative to the prior art, which will not be repeated here.

Description of drawings

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

1 is a schematic perspective view of a flow tube lab bench according to an embodiment of the present disclosure.

2 is a schematic perspective view of a flow tube test bench according to another embodiment of the present disclosure

3 is a schematic diagram of a three-dimensional structure of a flow channel measurement device according to an embodiment of the present disclosure.

FIG. 4 is a schematic front view of FIG. 3 .

FIG. 5 is a schematic top view of FIG. 3 .

FIG. 6 is a schematic structural diagram of a first conduit having an opening according to an embodiment of the present disclosure.

FIG. 7 is a schematic structural diagram of a first cover plate according to an embodiment of the present disclosure.

FIG. 8 is a partial cross-sectional view of FIG. 7 .

FIG. 9 is a schematic structural diagram of a second cover plate according to an embodiment of the present disclosure.

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

11 is a schematic diagram of a three-dimensional structure of a sound lining measurement device according to an embodiment of the present disclosure.

12 is an exploded schematic view of a mount according to an embodiment of the present disclosure.

13 is a schematic diagram of the assembly of a first tool and a microphone according to an embodiment of the present disclosure.

14 is a schematic cross-sectional view of a first tool according to an embodiment of the present disclosure.

15 is a schematic cross-sectional view of a second tool according to an embodiment of the present disclosure.

16 is a partial cross-sectional schematic view of a second tool and a second conduit according to an embodiment of the present disclosure.

FIG. 17 is a schematic cross-sectional structure diagram of FIG. 11 .

18 is a schematic perspective view of a receiver according to an embodiment of the present disclosure.

19 is a schematic bottom view of a second conduit according to an embodiment of the present disclosure.

20 is a schematic cross-sectional view of a combination of a mount and a microphone according to an embodiment of the present disclosure.

Detailed ways

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 used to explain the related content, but not to limit the present disclosure. In addition, it should be noted that, for the convenience of description, only the parts related to the present disclosure are shown in the drawings.

It should be noted that the embodiments of the present disclosure and the features of the embodiments may be combined with each other unless there is conflict. The present disclosure will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

As shown in Fig. 1-Fig. 3 and Fig. 11, the flow tube test bench according to the embodiment of the present invention is used for the acoustic experiment of the flow channel of the wide-speed domain flow. The flow tube test bench includes a flow measurement unit A, an acoustic measurement unit B and a The 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 pipeline 20 and a flow channel measurement device provided in the first pipeline 20, and the flow channel measurement The device is used for flow measurement at the two-dimensional section of the first pipe 20; the acoustic measurement unit includes a second pipe 910 and an acoustic lining measurement device provided in the second pipe 910, and the acoustic lining measurement device is used for acoustic measurement of the acoustic lining; The source unit C includes at least one third duct and a sound source device disposed in the third duct, and the sound source device is used to generate a broadband sound source.

In some embodiments, the detachable connection between the flow measurement unit A, the acoustic measurement unit B, and the sound source unit C makes the entire flow tube test bench adopt a modular design, which can be easily assembled, and the connection between the various units adopts The sealed connection allows the test bench to perform accurate measurements in the state of high-speed flow. At the same time, noise reduction is performed at the inlet and outlet of the pipeline so as not to affect the measurement accuracy of the acoustic measurement unit B.

The modular design allows any combination of units. For example, as shown in Figure 1, the flow measurement unit A can be set at any position, and the flow parameters at multiple sections can be measured, and the fluid upstream or downstream of the acoustic measurement unit B speed. As shown in FIG. 2 , one or more sound source devices in the sound source unit C can be moved, and combined with the flow measurement unit A and the acoustic measurement unit B, the forward and backward flow fields and sound fields can be obtained. In addition, one of the sound source devices can be replaced with a light wall section, and the remaining two sound source devices can be moved to the upstream and downstream of the acoustic measurement section respectively, and the sound field combined with the front pass and the back pass can be obtained. Unit B can monitor the forward and reverse sound transmission modes and noise reduction of the upstream and downstream of the acoustic lining. It can be understood that the combination of the above-mentioned units is only exemplary, and in some embodiments, the positional relationship between the units is not limited.

It can be understood that there can be multiple sound source devices in the above-mentioned sound source unit C, and each sound source device can be provided with three horns on each side wall of the third pipe, and the sound source device can be added according to actual needs. The number of , you can get a higher sound intensity sound source, increase or decrease the number can get a broadband sound source. When there are multiple sound source devices, one of the sound source devices can be replaced with a non-destructive rigid wall section to reduce the influence of the horn opening on the flow.

In some embodiments, 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 for flushing the inner walls of each pipeline . Specifically, among the connected flanges, one of them has a tapered positioning pin, and the other flange has a tapered positioning hole matched with the tapered positioning pin. When the two flanges are connected, the positioning The pins ensure that the inner walls of each pipe are flush. It can be understood that, in order to ensure sealing, a sealing ring is also provided between the connected flanges for sealing, so as to ensure the measurement accuracy of the flow channel.

In fact, a closed housing on the outside of the flow channel measuring device, the casing is used to seal the flow channel measuring device. The shell and the first pipeline are connected by bolts, and meanwhile, a sealing ring is used for sealing between the shell and the first pipeline and the shell. Threaded holes in the housing are used to lead out the wires of the measuring device. The hole can be plugged with a threaded plug to ensure a tight seal. The purpose of setting a closed casing on the flow channel measurement device is to prevent leakage caused by poor sealing of the flow channel measurement device, and the use of the casing for secondary measurement sealing can ensure the tightness of the first pipeline. For example, when the flow channel measurement device is not tightly sealed, and when the pressure in the housing is consistent with the pressure in the first pipeline, a similar sealing effect can also be achieved.

In order to realize the two-dimensional measurement of the probe of the flow field in the first pipeline, it is necessary to make the wall surface on which the probe is arranged as a sliding plate that moves in the direction perpendicular to the length of the first pipeline, but a sealing ring is used to seal the wall surface of the first pipeline. , a downward pressure is required to press the slide plate onto the first pipe, and the friction force formed cannot make the slide plate slide, so that the flow field measurement cannot be both airtight and convenient.

Referring to FIGS. 3 to 6 , an embodiment of the present invention provides a flow channel measurement device for multi-point measurement of a flow channel. The measurement device includes a probe 40 , a sliding plate 10 and a first pipe 20 forming a flow channel , the first wall surface 21 of the first pipe 20 has an opening, and the opening forms two side end surfaces 211 on the first wall surface 21. The side end surfaces 211 are the first inclined surfaces that reduce the diameter of the opening from the outside to the inside. Yes, in the direction from the outer surface of the first wall surface 21 to the inner wall, the openings respectively form bottom end surfaces 212 on the two side wall surfaces 22 of the first pipe 20, and the bottom end surfaces 212 are flush with the inner wall of the first wall surface 21. The end surface 211 and the two bottom end surfaces 212 are both provided with a first groove 213 for placing the fifth sealing ring; the sliding plate 10 is coordinated with the opening to form a closed flow channel for the first pipe 20, and the sliding plate 10 has a groove matching with the first inclined surface. The slide plate 10 is slidably arranged in the opening, and the probe 40 can move through the slide plate 10 and protrude into the flow channel; the outer side of at least one side wall surface 22 is provided with a force applying device, and the force applying device can be the first electromagnet 31, the first The electromagnet 31 attracts the sliding plate 10 for pressing the sliding plate 10 against the opening. The force applying device can also be a device that presses the sliding plate against the opening of the first pipe, such as a linear motor, a hydraulic cylinder or an air cylinder.

When the flow channel performs multi-point measurement, for example, the measurement is performed in one section of the flow channel, the probe 40 needs to be moved multiple times and the tightness of the first pipeline needs to be ensured. An opening is opened on the first wall surface 21 of the first pipe 20 , and the depth of the opening is consistent with the thickness of the first wall surface 21 , so that the bottom surface of the sliding plate 10 and the inner wall of the first wall surface 21 form a complete plane. The opening forms two opposite side end surfaces 211 on the first wall surface 21 of the first duct, and two opposite bottom end surfaces 212 are formed on the two side wall surfaces 22 of the first duct, and the side wall surfaces 22 are adjacent to the first wall surface 21. The two wall surfaces of the opening, wherein the side end surface 211 is a first inclined surface, and the first inclined surface is an inclined surface that gradually slopes downward in the direction of the center of the opening. The two opposite side end faces 211 and the two opposite bottom end faces 212 are used as the slideway of the slide plate 10. The slideway is also provided with a first groove 213, and a fifth sealing ring for sealing is arranged in the first groove 213. The position corresponding to the two opposite side end surfaces 211 has a slope matching with the first slope. When a downward pressing force is applied to the sliding plate 10, the fifth sealing ring at the first slope is subjected to both downward pressure and side pressure. The pressure ensures the tightness, and at the same time, the sliding plate and the first pipeline are matched with the inclined surface, so that the inner wall of the first wall surface 21 can form a complete plane.

On the outer side of the side wall surface 22, a first electromagnet 31 is provided below the sliding plate 10, and two first electromagnets 31 can be arranged on the outer side of the two side wall surfaces 22 of the first pipe respectively. The probe 40 can move through the sliding plate 10 and protrude into the flow channel. When the probe 40 moves to a target point, the first electromagnet 31 is energized, attracting the sliding plate 10 and giving the sliding plate 10 a downward pressing force to form a seal environment, take the measurement of the target point, or measure above or below the target point. When the probe 40 needs to be moved to another target point, the first electromagnet 31 is de-energized, the slide 10 can slide to the next position in the opening, the first electromagnet 31 is energized again to complete the sealing, and the probe 40 measures. Therefore, the contradiction that the sliding plate 10 cannot be moved due to the friction force generated by the fifth sealing ring for sealing is avoided. It can be understood that the material of the sliding plate 10 is a ferromagnetic material that can be attracted by an electromagnet, which is not specifically limited in some embodiments.

Please refer to FIGS. 6-9 , the slide 10 includes a first cover plate 11 and a second cover plate 12 , the first end surface 112 of the first cover plate 11 is matched with the second end surface 122 of the second cover plate 12 ; The upper section of the end surface 112 is provided with a raised portion 113 having a first cavity 1132 , and the lower end surface of the raised portion 113 is a second inclined surface 1131 ; The first concave portion of the body 1222, the first concave 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 cassette for accommodating the probe 40; The fourth inclined surface and the lower section of the second end surface 122 , or the third inclined surface 1221 of the protruding portion 113 and the lower section of the first end surface 112 are provided with a second groove 1224 for placing the sixth sealing ring.

In order to minimize the influence of the holes formed on the slide plate 10 by the probe 40 on the measurement, the slide plate 10 is composed of a first cover plate 11 and a second cover plate 12 that can be connected and separated. At the connection position of the second cover plate 12, a cassette is provided for accommodating the bent portion of the probe 40, that is, the detection portion. In addition to considering the first cover plate 11 and the second cover plate 12 for setting the cassette, the tightness of the connection between the two should also be considered. The first end surface 112 of the first cover plate 11 is at the upper section, that is, the part close to the upper surface of the first cover plate 11 , is provided with a raised portion 113 , and the lower end surface of the raised portion 113 is the second inclined surface 1131 , the second inclined surface 1131 The direction from the first cover plate 11 to the second cover plate 12 is inclined upward. Correspondingly, the second cover plate 12 is provided with a first concave portion that cooperates with the protruding portion 113 , and the first concave portion has a third inclined surface 1221 that cooperates with the second inclined surface 1131 . A second groove 1224 is provided on the peripheral side of the surface where the first concave part and the convex part 113 are matched with the sixth sealing ring. When sealing is required, the convex part 113 of the first cover plate 11 is pressed against the second cover plate 12 on the first recessed portion. It can be understood that a second groove 1224 is also provided at the part where the second end surface 122 of the second cover plate 12 is connected to the first end surface 112 of the first cover plate 11 for placing the sixth sealing ring.

Although not shown in the figure, it is understood that, at the connection position of the first cover plate 11 and the second cover plate 12, a sixth sealing ring can also be provided on the first end face 112 of the first cover plate 11 and the convex A groove is provided on the rising portion 113 for placing the sixth sealing ring, that is, a groove is provided at the position of the second inclined surface 1131 of the convex portion 113 and the lower section of the first end surface 112, and the lower section of the first end surface 112 refers to the It is the part below the lower edge of the boss 113 . Likewise, the lower portion of the second end surface 122 refers to the portion below the lower edge of the first recessed portion.

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

Further, a first cavity 1132 is provided on the convex portion 113, and a second cavity 1222 is provided on the lower part of the first concave portion. When the convex portion 113 is combined with the first concave portion, the first cavity 1132 and the first concave portion are combined. The second cavities 1222 together form a cassette for housing the probe 40 .

It can be understood that the upper surface of the raised portion 113 may be flush with the upper surface of the first cover plate 11 , or may be higher than the upper surface of the first cover plate 11 to form a boss 114 , please refer to FIG. 8 or FIG. 10 . Show.

Considering that the detection part of the probe 40 has a bent structure, when it is stored from the flow channel into the cassette, a certain gap is separated between the two cover plates, and is provided on the second cover plate 12 for the probe 40 to pass through. The through hole 1223 should have a notch. Specifically, the upper end surface of the above-mentioned raised portion 113 has a first through hole 1133 for the probe 40 to pass through, and the bottom surface 1225 of the first concave portion and the corresponding position of the first through hole 1133 have a first through hole 1133 for the probe 40 to pass through. Two through holes 1223 , the second end face 122 also has a notch for the probe 40 to translate out of the second end face 122 , and the notch communicates with the second through hole 1223 . It can be understood that the inner side wall of the second through hole 1223 also has a part of the second groove 1224 for placing the sixth sealing ring.

In actual operation, the two cover plates are separated by a certain gap, the probe 40 is separated from the first concave portion of the second end surface 122, the probe 40 is lifted up through the gap between the two cover plates and enters the cassette, the two cover plates reunite.

In some embodiments, in order to ensure the sealing connection between the first cover plate 11 and the second cover plate 12 , a pressure applying device needs to be provided, and the pressure applying device is used to connect the first cover plate 11 and the second cover plate 12 The connection part is pressed tightly to achieve a better seal.

In an optional embodiment, the pressing device includes a second electromagnet 32 disposed on the first cover plate 11, a connecting end plate 123 disposed on the second cover plate 12 opposite to the second electromagnet 32, The second electromagnet 32 attracts the connecting end plate 123 , so that the protruding portion 113 is pressed against the first concave portion. It can be understood that the end plate 123 is made of ferromagnetic material, which is vertically connected to the upper surface of the second cover plate 12, while the second electromagnet 32 is disposed on the upper surface of the first cover plate 11, and its suction surface is connected to the first cover plate 11. The two cover plates 12 are opposite to each other. When the two cover plates need to be connected, the second electromagnet 32 is energized, the two cover plates are pulled together by magnetic force, and good sealing is obtained at the part where the two cover plates are connected.

In some embodiments, the pressing device includes a first linear motion mechanism that drives the relative movement of the first cover plate 11 and the second cover plate 12 ; the first linear motion mechanism includes a fixed part 501 and a telescopic part 502 , and the fixed part 501 Set on the second cover 12, the telescopic portion 502 is connected to the first cover 11. When the telescopic portion 502 is elongated, a gap for the probe 40 to pass through is formed between the first end face 112 and the second end face 122; when the telescopic portion 502 extends When shortened, the raised portion 113 is pressed against the first recessed portion. The above-mentioned pressing device not only provides the tie force between the two cover plates to improve the sealing performance, but also automatically realizes the separation between the two cover plates.

Specifically, the first linear motion mechanism includes a fixed part 501 and a telescopic part 502 , wherein the fixed part 501 is provided on the second cover plate 12 to provide power for the telescopic part 502 , and the end of the telescopic part 502 is connected to the first cover plate 11 , which is optionally connected 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 is extended, and a gap for the probe 40 to pass through is formed between the two cover plates, and the above-mentioned cassette can be accommodated or extended. When the two cover plates need to be sealed and connected, the telescopic part 502 is shortened, and the convex part 113 is pressed against the first concave part, which not only provides the relative movement of the two cover plates, but also provides the tension between the two cover plates. knot strength, improve sealing.

It can be understood that the above-mentioned second electromagnet and the cover plate suction device and the first linear motion mechanism can be installed at the same time. When the two are installed at the same time, the end plate 123 is detachably installed on the second cover plate through the connecting piece. 12, optionally, a triangular connecting plate is connected to the opposite two sides of the end plate 123, 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 in the first Above the cover plate 11 , that is, between the second electromagnet 32 and the boss 114 .

Exemplarily, the above-mentioned first linear motion mechanism may be one of a linear motor, a hydraulic cylinder, and an air cylinder.

In some embodiments, the measuring device further 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 The movement mechanism 60 is used to cover the non-porous portion of the first cover plate 11 or the second cover plate 12 on the opening, and the third linear movement mechanism 70 retracts the probe 40 to the cassette; the second linear movement mechanism 60, the third linear movement mechanism 70 Each of the linear motion mechanisms 70 includes one of a linear motor, a hydraulic cylinder, an air cylinder or a ball screw.

3-4, the second linear motion mechanism 60 is used to control the reciprocating movement of the first cover plate 11 in the horizontal direction, and the third linear motion mechanism 70 is used to control the probe 40 to move in the vertical direction, thereby A two-dimensional measurement of the automated control probe 40 at the first pipe section is achieved. When the measurement 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 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 to the cassette, the second The linear motion mechanism 60 covers the non-porous part of the first cover plate 11 or the second cover plate 12 on the opening to form a complete inner wall of the first pipe.

Specifically, the second linear motion mechanism 60 and the third linear motion mechanism 70 each include one of a linear motor, a hydraulic cylinder, an air cylinder or a ball screw. The third linear motion mechanism 70 is vertically arranged above the boss 114. When the third linear motion mechanism 70 has a sliding slot slider, a clamp is provided on the slider, and the clamp clamps the upper half of the probe 40, while the sliding block is provided with a clamp. The block can be the nut part of the ball screw, which is driven by a motor to further control the movement of the slider. Similarly, the linear motion mechanism 70 is also a ball screw device, and its slider is fixedly connected with the chute of the third linear motion mechanism, so as to control the movement of the first cover plate 11 .

In some embodiments, the above-mentioned measuring device further includes a controller. In the first mode, the controller is used to control the second electromagnet 32 to engage with the end plate 123 , or to control the first linear motion mechanism to compress the protruding portion 113 On the first recess, the first electromagnet 31 is disconnected, and the probe 40 moves horizontally in the flow channel; in the second mode, the controller is used to control the second electromagnet 32 to disconnect from the end plate 123, or to control the first straight line The linear motion mechanism separates the convex portion 113 from the first concave portion, controls the third linear motion mechanism 70 to retract the probe 40 into the cassette, the first electromagnet 31 is disconnected, and the second linear motion mechanism 60 closes the first cover. 11 or the non-porous portion of the second cover plate 12 covers the opening.

Specifically, the controller is connected 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 respectively. When in the test mode, the controller The second electromagnet 32 is controlled to be energized and pulled in with the end plate 123 . The controller also controls the telescopic portion 502 of the first linear motion mechanism to shorten, so that the connection between the two cover plates has a certain tie force. When the test of a target point is completed, the first electromagnet 31 is controlled to be disconnected, and the first cover plate 11 can move in the horizontal direction, thereby realizing the horizontal movement of the probe 40 in the flow channel.

After completing the two-dimensional measurement of a section, the controller is also used to control the second electromagnet 32 to be powered off and disconnected from the end plate 123, and to control the first linear motion mechanism to separate the convex portion 113 from the first concave portion by a certain amount When there is a gap, the third linear motion mechanism 70 is controlled to retract the probe 40, the first linear motion mechanism is controlled to press the convex portion 113 with the first concave portion, and the probe 40 is placed in the cassette. The first electromagnet 31 is controlled to be disconnected, and the second linear motion mechanism 60 covers the non-porous part of the first cover 11 or the second cover 12 on the opening, and the non-porous part of the first cover 11 refers to the removal of The part other than the protruding part 113 and the non-porous part of the second cover plate 12 refer to the part other than the second through hole 1223 of the first concave part, that is, the second through hole 1223 is moved out of the first pipe opening.

Referring to FIG. 10 , in some embodiments, the above-mentioned measurement device further includes a sealing device for sealing the first through hole 1133 . The sealing device includes a clip 90 and a sealing ring 91 , and the sealing ring 91 is sleeved on the probe 40 . On the top, the clip 90 has a hole for the sealing ring 91 to be embedded in. The clip 90 is connected with the first cover plate 11 by adjusting bolts. The clip 90 seals the sealing ring, the first through hole 1133 and the probe 40. The sealing ring The height of 91 is greater than the depth of the hole of clip 90 .

Specifically, the sealing ring 91 is sleeved on the probe 40 and the clip 90 of the probe 40, the clip 90 is located on the sealing ring 91, and a plurality of adjustment bolts are arranged on the peripheral side of the clip 90. When there is a through hole 1133, a plurality of adjustment bolts are tightened on the peripheral side of the first through hole 1133, and the clip 90 is pressed against the elastic sealing ring 91, so as to realize the gap between the sealing ring 91, the first through hole 1133 and the probe 40. seal. By adjusting the pre-tightening force of the bolt, the probe 40 can be moved up and down in the first through hole 1133 .

In an optional embodiment, the clip 90 has a stepped hole, the sealing ring 91 is arranged in the stepped hole, and a part of the sealing ring 91 protrudes from the bottom of the clip 90, so as to realize the limit of the sealing ring 91, so as to realize more good sealing effect.

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 . Probe 40 may be a pitot tube.

In some embodiments, the above-mentioned first pipe 20 is further provided with two sliding grooves 80 on the outer side of the electromagnet. Swipe in.

In some embodiments, L-shaped limit blocks are also provided on the outer sides 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 blocks is set above the edge of the slide plate 10 , not with the The sliding plate 10 is in contact, and the limit block is used to prevent the sliding plate from overturning and falling off.

During the acoustic measurement in the environment of high flow rate and high pressure difference, there is a large pressure difference between the inside and outside, which will exert a suction force towards the inside of the second pipe to the microphone itself. The microphone exerts sufficient force. Secondly, the microphone will be disassembled and assembled frequently in the experiment. Repeated disassembly and assembly will cause irreversible damage to the connection of the power cord of the microphone. At the same time, the disassembly and assembly of the microphone must also be convenient, easy to locate, and easy to fix.

Referring to FIGS. 11 to 12 , an embodiment of the present invention provides an acoustic lining measurement device, including a second duct 910 , a microphone 924 , a casing 930 , and an acoustic lining disposed between the second duct 910 and the casing 930 . Lining, the end surface of the perforated plate of the acoustic lining is flush with the inner wall of the third wall surface 911 of the second pipe 910, the microphone 924 is arranged on the second wall surface 912 of the second pipe 910 opposite to the third wall surface 911, and the microphone 924 The receiving end is flush with the inner wall of the second wall surface 912; at least one microphone 924 is detachably arranged on the second wall surface 912 through the mounting seat 920, and the mounting seat 920 includes a first tooling 921 and a second tooling 922 arranged on the second wall 912 The first tooling 921 and the second tooling 922 both have a cavity for the microphone 924 to pass through. The first tooling 921 is used for holding the microphone 924 , and the first tooling 921 is detachably connected to the second tooling 922 .

Specifically, the second duct 910 has a third wall surface 911 and a second wall surface 912 that are opposite to each other, and the microphone 924 is detachably disposed on the second wall surface 912 through the mounting seat 920. It can be understood that the number of microphones 924 can be one, or can be A plurality of microphones 924 are provided along the airflow direction of the second duct 910 . The opening of the casing 930 communicates with the opening of the second wall surface 912 of the second duct 910, the acoustic lining is provided between the opening of the casing 930 and the opening of the third wall surface 911 of the second duct 910, and the acoustic lining is The upper surface of the perforated plate is flush with the inner wall of the second wall surface 912, and the lower end surface of the microphone 924 is flush with the inner wall of the second wall surface 912, so as to avoid affecting the airflow of the second pipe 910, and the measurement result is accurate.

Exemplarily, the mounting seat 920 includes a first tool 921 and a second tool 922, wherein the second tool 922 is detachably provided on the second wall 912, and the first tool 921 is detachably arranged on the second tool 922, and the second tool 922 is detachably provided on the second tool 922. Both the first tool 921 and the second tool 922 have cavities for the microphone 924 to pass through. Since the lower end of the microphone 924 is larger than other parts, only one tool is used to mount on the second pipe, and the tool also clamps the microphone 924. The microphone 924 cannot be taken out without disassembling the tool. However, if the tooling is to be disassembled, the long-term disassembly and assembly will affect the sealing effect between the second pipe 910 and the mounting seat 920 . Therefore, the embodiment of the present invention adopts the mode of the first tooling 921 and the 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, so as to protect the sealing between the second pipe 910 and the mounting seat 920 from damage.

Considering that the internal pressure of the second pipe is much lower than the atmospheric pressure when performing acoustic measurement in an environment with high flow rate and high pressure difference, and when the microphone is working, its static pressure hole needs to be connected to the inside of the second pipe, which is very important for the microphone mount. A request for sealing is made. As shown in FIG. 20 , sealing rings are provided at the connection position between the microphone 924 and the first tool 921 , the connection position between the first tool 921 and the second tool 922 , and the connection position between the second tool 922 and the second wall 912 . The static pressure hole 9241 of the microphone 924 is located below the connection position of the microphone 924 and the first tooling 921, so that the static pressure hole 9241 is communicated with the inside of the second pipe through the cavity of the first tooling 921 and the second tooling 922, and is Sealing rings are provided at the connection position between the first tooling 921 and the second tooling 922 and at the connecting position between the second tooling 922 and the second wall surface 912 to ensure that the static pressure hole 9241 is communicated with the inside of the second pipe 910 and is not affected by atmospheric pressure. interference, so that the microphone 924 works normally.

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 outside, and in order to conveniently disassemble the microphone 924 on the first tooling 921, the embodiment of the present invention adopts the form of a clamp Clamp. Referring to FIGS. 2 to 14 , the first tool 921 has a clamping portion. The clamping portion includes a clamp 923 and a plurality of petal-shaped constricted portions 9211 spaced along the circumferential direction of the first tool 921 . The clamp 923 is sleeved At the constricted portion 9211, the constricted portion 9211 clamps the microphone 924 under the action of the clamp 923; the cavity of the first tooling 921 is provided with a first groove 9213 for accommodating the first sealing ring 941 at the position close to the constricted portion 9211. A sealing ring 941 is used for sealing the first tool 921 and the microphone 924 .

When the microphone 924 is assembled on the first tooling 921, the microphone 924 passes through the cavity of the first tooling 921 and the first sealing ring 941 set in the first groove 9213, and tightens the clamp 923 after positioning. Under the action of the hoop 923, the plurality of lobed constricted parts 9211 arranged on the first tooling 921 in the circumferential direction clamp the microphone 924, and the static pressure hole 9241 of the microphone 924 is located in the cavity below the first sealing ring 941, Thus, it is ensured that the static pressure hole 9241 communicates with the inside of the second pipe 910 and is not disturbed by atmospheric pressure. When the microphone 924 is detached from the first tooling 921, it is only necessary to loosen the clamp 923, and then it can be detached. Therefore, the use of the form of a clamp not only provides sufficient clamping force, but also facilitates disassembly and assembly.

Considering that the lower end surface of the microphone 924 is to be flush with the inner wall surface of the second wall surface 912, and the microphone 924 needs to be adjusted in height, the heights of the first tool 921 and the second tool 922 should have known heights. In order to ensure that the heights of the first tooling 921 and the second tooling 922 are constant, for example, as shown in FIGS. 15-16 , the cavity of the second tooling 922 has a first stepped surface 9222 , a second wall surface 912 and a first step surface 9222 . There is a second stepped surface 9121 at the connecting position of the two tooling 922 , the third end surface 9214 of the first tooling 921 facing away from the clamping portion abuts on the first stepped surface 9222 , and the fourth end surface of the second tooling 922 facing away from the first tooling 921 9223 abuts on the second stepped surface 9121.

Specifically, when the first tool 921 is connected to the second tool 922 , the third end surface 9214 of the first tool 921 abuts on the first stepped surface 9222 , and the first stepped surface 9222 may be a part of the second groove 9221 , wherein the second groove 9221 is used to place the fourth sealing ring 944 for sealingly connecting the first tool 921 to the second tool 922 . The first step surface 9222 is used for the position limit of the first tooling 921 . Similarly, there is a second stepped surface 9121 at the connection position between the second wall surface 912 and the second tool 922 . When the second tool 922 is connected to the second wall surface 912 , a second stepped surface 9121 is provided in the through hole of the second wall surface 912 , so that the fourth end surface 9223 of the second tooling 922 abuts on the second stepped surface 9121 . When the first tooling 921 and the second tooling 922 are both connected, the height of the entire mounting seat 920 is fixed. At this time, according to the known length of the microphone 924, the microphone 924 can be fixed before the mounting seat is installed, so that Its lower end surface is flush with the inner wall of the second wall surface 912 after being installed on the second pipe 910 .

In some embodiments, as shown in FIGS. 14-16 , the first tool 921 is screwed with the second tool 922 ; the second tool 922 is screwed with the second wall 912 . For example, the first tool 921 has external threads, the second tool 922 has corresponding internal threads, and the first tool 921 can be connected to the second tool 922 through threads. Similarly, the through hole of the second wall surface 912 has an internal thread, and the other end of the second tool 922 has an external thread, and the second tool 922 can be connected to the second wall surface 912 by a thread. The first tooling 921 and the second tooling 922, and the second tooling 922 and the second wall surface 912 can also be connected by clipping. The cavity is provided with a card slot suitable for snapping; similarly, the other end of the second tooling 922 has an elastic snap, and the through hole of the second wall surface 912 has a card slot suitable for snapping.

Since the head of the microphone is threadedly connected to the wire, in order to prevent the interface of the microphone 924 from being damaged due to excessive rotation when the first tool 921 and the microphone 924 are screwed into the second tool 922 as a whole, and the first tool 921 is in use during use The microphone 924 as a whole is often disassembled and assembled. For example, when the first tool 921 is screwed with the second tool 922, the first tool 921 has an external thread segment 9212, and the number of thread turns of the external thread segment 9212 is 1-4. , the thread is coarse. The design of coarse teeth is adopted to ensure that the first tooling 921 has enough force to apply to the first sealing ring 941 and reduce the number of threads as much as possible. This application uses 1-4 threads of threads, optionally 1.5 threads. , 2.5 circles, etc.

Please refer to FIGS. 15-16 , in order to ensure the sealing between the second tooling 922 and the second wall surface 912 and the installation height of the second tooling 922 , the second tooling 922 has a connection with the second wall surface 912 Section 9225, 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, where a>b; the above distance a>b ensures that the second tooling 922 When mounted on the second wall surface 912 , the fourth end surface 9223 of the second tooling 922 can be abutted on the second stepped surface 9121 .

Exemplarily, the second tooling 922 has a third stepped surface 9224 at a position close to the connecting section 9225, and the connecting section 9225 between the third stepped surface 9224 and the outer surface of the second wall surface 912 is sleeved with a second sealing ring 942, The second sealing ring 942 is used for sealing between the second tooling 922 and the second wall surface 912 . Specifically, the second sealing ring 942 is sleeved on the connecting section 9225. When the second tooling 922 is connected to the second wall surface 912, the second sealing ring 942 is pressed against the outer surface of the second wall surface 912 by the third step surface 9224. , so as to achieve the sealing of the two and ensure the accuracy of the measurement results of the acoustic lining.

Considering the installation of the acoustic lining and the high flow rate environment, the pressure difference inside and outside the casing is extremely large. Once air leakage occurs, the measurement results will be deviated. Exemplarily, the casing of the casing 930 is integrally formed to ensure the tightness of the casing; the casing 930 is detachably connected to the second pipe 910; for example, bolts are used for connection. The casing 930 has a cavity for accommodating the acoustic lining. The cavity is provided with a bottom plate 931 abutting against the end face of the acoustic lining facing away from the perforated plate. The position of the bottom plate 931 in the casing 930 is adjustable, and the bottom plate 931 is used to seal the acoustic lining. in receiver 930. The bottom plate 931 with adjustable position is used to abut the end face of the acoustic lining away from the perforated plate, so that the acoustic lining has no extra gap in the casing, or the acoustic lining is sealed in the casing, so that the acoustic lining will not be in the casing. Creates a pressure differential with the second conduit. However, since the acoustic lining is used as a noise reduction element applied in multiple scenarios, its type and height are not fixed, and the depth of the machined casing is fixed, so the use of the position-adjustable bottom plate 931 can be applied to acoustic linings of different heights , and to ensure the tightness of the acoustic lining in the casing.

Specifically, the cavity of the casing 930 is provided with one or more adjustment devices 932 for adjusting the bottom plate 931. As shown in FIG. 17, the adjustment device 932 is disposed between the bottom plate 931 and the third wall surface 934, and the third wall surface 934 is On the bottom surface of the casing 930 opposite to the bottom plate 931, the adjustment device 932 includes a threaded sleeve 9322 and a stud 9321. The relative movement of the stud 9321 and the threaded sleeve 9322 makes the bottom plate 931 abut against the end face of the acoustic liner facing away from the perforated plate. The stud 9321 is rotatably arranged on the third wall surface 934, and the screw sleeve 9322 is arranged on the bottom plate 931. By adjusting the stud 9321, the position of the bottom plate 931 in the receiver is adjusted so that the bottom plate 931 abuts on the bottom surface of the acoustic liner to be tested. It can be understood that the studs 9321 can be disposed on the bottom plate 931 and the screw sleeves 9322 can be disposed on the third wall surface 934 , and the height of the bottom plate 931 can also be adjusted.

In order to ensure the sealing between the casing 930 and the second pipe 910, and that the outer surface of the perforated plate of the acoustic lining is flush with the inner wall surface of the third wall surface 911, please refer to FIGS. 18-19. A lug plate 933 protruding from the casing 930 is provided at the connection position between the 930 and the second pipe 910. The second pipe 910 has a second concave portion 913 that cooperates with the lug plate 933. The wall of the second concave portion 913 is provided with There is a third sealing ring, and the third sealing ring is used for sealing between the casing 930 and the second pipe 910 . The perforated plate of the acoustic lining is slightly larger than other parts of the acoustic lining, and can just overlap the upper surfaces of the two lugs 933 protruding from the casing 930. The acoustic lining is pressed against the ear plate 933, ensuring that the upper surface of the acoustic lining and the lower surface of the second pipe are in the same plane. It will be appreciated that although two lugs 933 are shown, in some embodiments there may be four lugs 933 around the open perimeter of the receiver. Further, there is a groove on the wall surface of the second concave portion 913 of the second pipe 910 for placing the third sealing ring, thereby ensuring the sealing between the casing 930 and the second pipe 910 after the acoustic liner is placed.

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 is passed through the first tooling 921, and the clamp 923 is put on the constricted part 9211 for pre-tightening , forming the first component;

Install the second sealing ring 942 on the second groove 9221 of the second tooling 922, and install the first component on the second tooling 922;

Set the fourth sealing ring 944 on the connecting section 9225 of the second tooling 922, install it in the through hole of the second wall 912, adjust the relative height of the microphone 924 and the first tooling 921, and finally tighten the clamp 923, clamping the microphone 924, the lower end surface of the microphone 924 can be realized to be flush with the inner wall surface of the second wall surface 912, because the heights of the first tooling 921 and the second tooling 922 are fixed;

Then, according to the height of the acoustic lining, adjust the height of the bottom plate 931 inside the casing through the adjusting device 932 so that it abuts on the bottom surface of the acoustic lining;

When the test is completed, the microphone 924 needs to be removed or replaced. Only the first tool 921 and the microphone 924 it holds are removed, and then the clamp is released. The second tool 922 does not need to be disassembled frequently.

The embodiment of the present invention also provides a flow pipe measurement method, including the measurement device in the above technical solution. The above-mentioned flow tube measurement method includes the following steps:

Step 1: The first electromagnet 31 and the second electromagnet 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; Flow parameters include total temperature, total pressure, static temperature, velocity field, velocity vector, boundary layer information, flowing particle field, sound pressure spatial distribution, etc., and other physical quantities are calculated from this.

Step 2: The first electromagnet 31 is powered off, the second electromagnet 32 is powered on, and 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 to drive the first cover plate 11 and the second cover plate 12 The probe 40 on a cover plate 11 reaches the second target point, the first electromagnet 31 is energized, the two cover plates are pressed against the opening of the first pipe 20, and the probe 40 measures the flow parameter of the second target point;

Step 3: Repeat the above steps 1 and 2, when the measurement of all the target points on the section of the first pipe 20 is completed, the first electromagnet 31 is powered off, and the first linear motion mechanism drives the first cover 11 and the first The two cover plates 12 are separated by a certain gap for retracting the probe 40 from the flow channel, the third linear motion mechanism 70 recovers the probe 40 to the cassette, and the first linear motion mechanism drives the first cover 11 and the second cover 12 to combine , the gap between the two is eliminated;

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 moves to the opening of the first pipe. On the outside, the non-porous parts of the two cover plates cover the opening, and a complete flow channel wall surface is formed on the inner wall of the first pipe 20, so as to avoid the influence of the second through hole on the flow field.

Before step 1 above, you can also include:

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, put the clamp 923 on the constriction 9211, and pre-tighten it to form the first components;

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

Step 12: Set the fourth sealing ring 944 on the connecting section 9225 of the second tooling 922, then install it in the through hole of the second wall 912, adjust the relative height of the microphone 924 and the first tooling 921, and finally close it. Tighten the clamp 923 and clamp the microphone 924, so that the lower end surface of the microphone 924 can be flush with the inner wall surface of the second wall surface 912;

Step 13: The adjustment device 932 adjusts the height of the bottom plate 931 inside the casing so that it abuts against the bottom surface of the acoustic lining to form a seal for the acoustic lining.

After the above step 4, it can also include:

Step 5: Monitor the sound transmission mode and noise reduction amount of the sound lining through the microphone 924 disposed on the second wall 912 .

It can be understood that, in the above-mentioned acoustic measurement step, the microphone 924 can be arranged as a microphone array matched with the corresponding extraction method, so as to achieve accurate measurement of the acoustic lining acoustic impedance in a wide enough frequency band.

In the actual measurement, as shown in Figure 1 or 2, firstly, the flow measurement unit is sealed by controlling the on-off of the electromagnet in the flow measurement device, and the displacement movement mechanism moves the probe in the vertical and horizontal directions, so as to realize the first step. Flow parameter measurement at the entire two-dimensional cross-section of a pipeline. After the measurement of the entire cross-section is completed, the displacement mechanism of the probe retracts the probe into the cassette. The displacement mechanism of the probe moves the first cover plate and the second cover plate as a whole, and covers the non-porous part of the cover plate on the opening, so that the inner wall of the first pipe forms a complete flow channel wall surface, and then the The fluid flow of the second pipe will be more uniform, and no additional noise will be generated. When the acoustic lining measurement device performs the acoustic measurement, the measurement result is closer to the actual situation.

The flow tube test bench of the embodiment of the present invention combines a high-speed flow tube with a two-dimensional measurement mechanism, which solves the problem of tightness of the measurement mechanism under high flow rate. The whole device can not only be assembled modularly to realize the measurement of sound transmission modes and noise reduction under various sound source conditions, but also completely eliminate the influence of the fluid measurement probe on the fluid in the flow channel. Acoustic measurements.

In the description of this specification, references to the terms "one embodiment/mode", "some embodiments/modes", "example", "specific example", or "some examples", etc. are intended to be combined with the description of the embodiment/mode A particular feature, structure, material, or characteristic described by way of example or example is included in at least one embodiment/mode or example of the present application. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment/mode or example. Furthermore, the particular features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments/means or examples. Furthermore, those skilled in the art may combine and combine the different embodiments/modes or examples described in this specification and the features of the different embodiments/modes or examples without conflicting each other.

In addition, the terms "first" and "second" are only used for descriptive purposes, and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, a feature delimited with "first", "second" may expressly or implicitly include at least one of that feature. In the description of the present application, "plurality" means at least two, such as two, three, etc., unless expressly and specifically defined otherwise.

Those skilled in the art should understand that the above-mentioned embodiments are only for clearly illustrating the present disclosure, rather than limiting the scope of the present disclosure. For those skilled in the art, other changes or modifications may also be made on the basis of the above disclosure, and these changes or modifications are still within the scope of the present disclosure.

Claims (26)

1. A flow tube experiment table is characterized by being used for acoustic experiments of a flow channel of wide-speed-domain flow, and comprising a flow measurement unit, an acoustic measurement unit and a sound source unit, wherein the flow measurement unit, the acoustic measurement unit and the sound source unit are detachably connected;

the flow measuring unit comprises a first pipeline and a flow channel measuring device arranged on the first pipeline, and the flow channel measuring device is used for flow measurement at the position of a two-dimensional section of the first pipeline;

the acoustic measurement unit comprises a second pipeline and an acoustic lining measurement device arranged on the second pipeline, and the acoustic lining measurement device is used for acoustic measurement of an acoustic lining;

the sound source unit comprises at least one third pipeline and a sound source device arranged on the third pipeline, and the sound source device is used for generating a broadband sound source.

2. The experiment table according to claim 1, wherein the first pipeline, the second pipeline and the third pipeline are connected through flanges, and the two connected flanges are positioned through positioning pins, wherein the positioning pins are used for enabling the inner wall surfaces of the pipelines to be flush.

3. The experimental station of claim 1, wherein the flow measurement unit further comprises a sealed housing disposed outside the flow channel measurement device, the housing being configured to seal the flow channel measurement device.

4. The experiment table according to claim 1, wherein the flow channel measuring device comprises a probe and a sliding plate, the first wall surface of the first pipeline is provided with an opening, the opening forms two side end surfaces on the first wall surface, the side end surfaces are first inclined surfaces which enable the caliber of the opening to become smaller from outside to inside, the opening respectively forms bottom end surfaces on the two side wall surfaces of the first pipeline, the bottom end surfaces are flush with the inner wall of the first wall surface, and the two side end surfaces and the two bottom end surfaces are provided with first grooves for placing fifth sealing rings;

the sliding plate is matched with the opening to form a closed flow passage for the first pipeline, the sliding plate is provided with an inclined surface matched with the first inclined surface, the sliding plate is arranged at the opening in a sliding mode, and the probe movably penetrates through the sliding plate and extends into the flow passage;

and a force application device is arranged on the outer side of at least one side wall surface and is used for pressing the sliding plate on the opening.

5. The lab table of claim 4, wherein the slide plate comprises a first cover plate and a second cover plate, a first end surface of the first cover plate mating with a second end surface of the second cover plate;

the upper section of the first end surface is provided with a bulge part with a first cavity, and the lower end surface of the bulge part is a second inclined surface;

the upper section of the second end face is provided with a first concave part which is matched with the convex part and is provided with a second cavity, the first concave part is provided with a third inclined plane matched with the second inclined plane, and the first cavity is matched with the second cavity to form a cassette for accommodating the probe;

and a second groove for placing a sixth sealing ring is formed in the third inclined surface of the first concave part and the lower section of the second end surface, or the second inclined surface of the convex part and the lower section of the first end surface.

6. The experiment table according to claim 5, wherein the upper end face of the protruding part is provided with a first through hole for the probe to pass through, the lower end face of the first recessed part is provided with a second through hole for the probe to pass through at a position corresponding to the first through hole, the second end face is further provided with a notch for the probe to translate, and the notch is communicated with the second through hole.

7. The experimental bench of claim 6, wherein the measuring device further comprises a pressing device for pressing the connection portion of the first cover plate and the second cover plate.

8. The experiment table according to claim 7, wherein the pressing device comprises a second electromagnet arranged on the first cover plate, and a connecting end plate arranged on the second cover plate and opposite to the second electromagnet, and the second electromagnet attracts the connecting end plate so that the convex part is pressed on the first concave part.

9. The experiment table according to claim 8, wherein the pressing device comprises a first linear motion mechanism for driving the first cover plate and the second cover plate to move relatively;

the first linear motion mechanism comprises a fixing part and a telescopic part, the fixing part is arranged on the second cover plate, the telescopic part is connected with the first cover plate, and when the telescopic part extends, a gap for the probe to pass through is formed between the first end surface and the second end surface; when the telescopic part is shortened, the convex part is pressed on the first concave part.

10. The experimental station of claim 9, wherein the first linear motion mechanism comprises one of a linear motor, a hydraulic cylinder, and a pneumatic cylinder.

11. The experiment table according to claim 9, wherein the measuring device further comprises a second linear motion mechanism driving the first cover plate to slide, and a third linear motion mechanism arranged on the first cover plate;

when the measuring device is in a first mode, the second linear motion mechanism is used for driving the probe to move in the first direction in the flow channel, and the third linear motion mechanism is used for driving 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 cassette, and the second linear motion mechanism is used for covering the imperforate 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 respectively comprise one of a linear motor, a hydraulic cylinder, an air cylinder or a ball screw.

12. The experimental bench of claim 11, wherein the measuring device further comprises a controller, the force applying device is a first electromagnet, in the first mode, the controller is configured to control the second electromagnet to attract with the end plate, or control the first linear motion mechanism to press the protruding portion against the first recessed portion, the first electromagnet is turned off, and the probe moves horizontally in the flow channel;

in the second mode, the controller is configured 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 recess, control the third linear motion mechanism to retract the probe into the cassette, disconnect the first electromagnet, and control the second linear motion mechanism to cover the non-porous portion of the first cover plate or the second cover plate on the opening.

13. The laboratory bench of claim 11, wherein the measuring device further comprises a sealing device for sealing the first through hole, the sealing device comprises a clamping piece and a sealing ring, the sealing ring is sleeved on the probe, the clamping piece has a hole for the sealing ring to be embedded in, the clamping piece is connected with the first cover plate through an adjusting bolt, the clamping piece is used for sealing 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 clamping piece.

14. The experiment table according to claim 12, wherein the number of the first electromagnets is two, and the two first electromagnets are respectively arranged on two sides of the first pipeline;

each electromagnet is also provided with a sliding groove matched with the corresponding cover plate on the outer side, and the cover plate is arranged in the corresponding sliding groove in a sliding manner.

15. The experimental bench of claim 1 wherein the acoustic liner measuring device comprises a microphone, a casing, and an acoustic liner disposed between the second pipe and the casing, the acoustic liner having a perforated plate with an end surface flush with an inner wall of a first wall surface of the second pipe, the microphone being disposed on a second wall surface of the second pipe opposite the first wall surface, a receiving end of the microphone being flush with the inner wall of the second wall surface;

at least one microphone can be dismantled through the mount pad and establish the second wall, the mount pad includes first frock and establishes the second frock of second wall, first frock the second frock all has the confession the cavity that the microphone passed, first frock is used for the centre gripping the microphone, first frock can dismantle connect in the second frock.

16. The experiment table according to claim 15, wherein sealing rings are arranged at the connecting position of the microphone and the first tool, the connecting position of the first tool and the second tool, and the connecting position of the second tool and the second wall surface.

17. The experiment table according to claim 15, wherein the first tool is provided with a clamping portion, the clamping portion comprises a hoop and a plurality of petal-shaped constrictions arranged at intervals along the circumferential direction of the first tool, the hoop is sleeved on the constrictions, and the constrictions clamp the microphone under the action of the hoop;

a first groove for containing a first sealing ring is formed in the position, close to the contraction portion, of the cavity of the first tool, and the first sealing ring is used for sealing the first tool and the microphone.

18. The experiment table according to claim 15, wherein a cavity of the second tool is provided with a first step surface, a connecting position of the second wall surface and the second tool is provided with a second step surface, a third end surface of the first tool, which is far away from the clamping portion, abuts against the first step surface, and a fourth end surface of the second tool, which is far away from the first tool, abuts against the second step surface.

19. The experiment table according to any one of claims 15 to 19, wherein the first tool is in threaded connection or clamped connection with the second tool; and the second tool is in threaded connection or clamped connection with the second wall surface.

20. The experiment table according to claim 19, wherein when the first tool is in threaded connection with the second tool, the first tool is provided with an external thread section, the number of thread turns of the external thread section is 1-4, and the thread is a coarse thread.

21. The experimental bench of claim 19, wherein the second fixture has a connecting section connected with the second wall surface, the connecting section has a length of a, and the distance between the second step surface and the outer surface of the second wall surface is b, wherein a > b;

the second frock is close to linkage segment position department has the third step face, is located the third step face with linkage segment cover between the surface of second wall is equipped with the second sealing washer, the second sealing washer is used for the second frock with seal between the second wall.

22. The laboratory bench of claim 19 wherein said housing is removably connected to said second conduit;

the casing is provided with a cavity for accommodating the sound liner, a bottom plate which is abutted to the end face, away from the perforated plate, of the sound liner is arranged in the cavity, the position of the bottom plate on the casing is adjustable, and the bottom plate is used for sealing the sound liner in the casing.

23. The experimental bench of claim 22 wherein at least one adjusting device for adjusting the bottom plate is disposed in the cavity of the casing, the casing has a third wall surface opposite to the bottom plate, the adjusting device is disposed between the bottom plate and the third wall surface, the adjusting device comprises a threaded sleeve and a threaded stud, and the bottom plate abuts against the end surface of the acoustic backing away from the perforated plate through the relative movement of the threaded stud and the threaded sleeve.

24. The experimental bench of claim 22, wherein a lug protruding from the casing is disposed at a connection position of the casing and the second pipe, the second pipe has a second recess engaged with the lug, and a wall surface of the second recess is provided with a third sealing ring for sealing between the casing and the second pipe.

25. A flow tube measurement method, characterized in that it is applied to the laboratory bench of any one of claims 1 to 24, said measurement method comprising:

the first electromagnet and the second electromagnet are electrified, 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, the second electromagnet is powered on, the second linear motion mechanism drives the probe to reach a 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 finished, the first electromagnet is powered off, the first linear motion mechanism drives the first cover plate and the second cover plate to be separated, and the third linear motion mechanism recovers the probe to the cassette;

the first electromagnet is powered off, and the second linear motion mechanism seals the imperforate part of the first cover plate or the second cover plate on the opening.

26. The measurement method according to claim 25, further comprising:

arranging the acoustic liner between the second pipe and the casing, aligning the end face of the perforated plate of the acoustic liner with the inner wall of the first wall surface of the second pipe, adjusting the adjusting device, abutting the bottom plate against the acoustic backing to separate from the end face of the perforated plate,

and the microphone is arranged on the second wall surface through the mounting seat, and the receiving end of the microphone is flush with the inner wall of the second wall surface, so that acoustic measurement is carried out on the acoustic liner.

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