CN219064823U

CN219064823U - Open direct current wind tunnel and jet noise tester

Info

Publication number: CN219064823U
Application number: CN202222885384.2U
Authority: CN
Inventors: 孙菁微; 陶立进; 周培好
Original assignee: Beijing Aerospace Sanfa High Tech Co Ltd
Current assignee: Beijing Aerospace Sanfa High Tech Co Ltd
Priority date: 2022-10-31
Filing date: 2022-10-31
Publication date: 2023-05-23
Anticipated expiration: 2032-10-31

Abstract

The embodiment of the disclosure discloses an open direct current wind tunnel and jet noise tester. The open direct current wind tunnel comprises: the jet flow part comprises an air inlet section, a stabilizing section, a contraction section and a nozzle section which are sequentially connected, one end of the air inlet section is an air inlet, the air inlet is communicated with an air source, and one end of the nozzle section is an air jet; the collecting part comprises a collecting port section, a first diffusion section, a first corner section, a horizontal pipeline silencing section, a fan section and a second diffusion section which are sequentially connected, one end of the collecting port section is a collecting port, the collecting port is opposite to the air jet, and one end of the second diffusion section is an exhaust port; the jet flow part is configured to rectify and discharge initial gas generated by the gas source from the gas jet port, the gas discharged from the gas jet port is denoted as first gas, and the collecting part is configured to collect the first gas and discharge the first gas from the gas outlet.

Description

Open direct current wind tunnel and jet noise tester

Technical Field

The utility model relates to the technical field of jet noise tests, in particular to an open direct current wind tunnel and a jet noise tester.

Background

Noise caused by turbulent flow, which is strongly pulsating due to the rapid mixing of the high-speed air flow emitted from the nozzle with the surrounding medium, is called jet noise. The jet noise is in direct proportion to the jet speed and the exhaust pressure, namely, the jet noise is larger as the jet speed is higher, and the jet noise is larger as the exhaust pressure is higher.

The study of jet noise is very important in certain fields, such as rockets, exhaust jet noise of aeroengines, etc. Jet noise has a great influence on the mechanical and acoustic properties of the relevant equipment, and can cause vibration and aggravate mechanical breakage, and simultaneously, the generated noise can also cause great noise pollution to the external environment. In the prior art, various jet noise simulation test devices are provided to further study how to eliminate jet noise. However, in the jet noise simulation test device in the prior art, due to the limitation of the wind tunnel structure, the flow field meeting the requirements on the wind tunnel nozzle or the speed, the uniformity and the turbulence degree cannot be obtained. In addition, in the wind tunnel structure in the prior art, the gas sprayed out of the nozzle is not timely recovered, backflow is easily generated in the wind tunnel body, and further opposite gas resistance is generated for a jet noise test, so that the safety and accuracy of the test are reduced.

Therefore, a new solution is needed to solve the above-mentioned problems.

Disclosure of Invention

It is an object of the present disclosure to provide a new solution for an open direct current wind tunnel.

According to a first aspect of the present disclosure, an open dc wind tunnel is provided. The open direct current wind tunnel comprises:

a sound-deadening chamber;

the jet flow part comprises an air inlet section, a stabilizing section, a contraction section and a nozzle section which are sequentially connected, wherein one end of the air inlet section is an air inlet, the air inlet is communicated with an air source, one end of the nozzle section is an air jet port, the diameter of the stabilizing section is larger than that of the contraction section, and the diameter of the contraction section is larger than that of the nozzle section;

the collecting part comprises a collecting port section, a first diffusion section, a first corner section, a horizontal pipeline silencing section, a fan section and a second diffusion section which are sequentially connected, one end of the collecting port section is a collecting port, the collecting port is opposite to the air jet, and one end of the second diffusion section is an exhaust port;

the jet flow part and the collecting part are arranged at intervals, the jet flow part and the collecting opening part are both positioned in the silencing chamber, under the condition of jet flow noise test, the jet flow part is configured to rectify the initial gas generated by the gas source and discharge the initial gas from the gas jet port, the gas discharged from the gas jet port is recorded as first gas, and the collecting part is configured to collect the first gas and discharge the first gas from the gas outlet.

Optionally, the air inlet extends outwardly in an arc in a direction towards the air source.

Optionally, the shrink ratio of the shrink section is 9.

Optionally, the single-sided diffusion angle of the collecting opening is 3-5 degrees.

Optionally, a honeycomb device and a damping net are arranged in the stabilizing section, the honeycomb device is arranged at one end close to the air inlet, and the damping net is arranged at one end far away from the honeycomb device and close to the air jet.

Optionally, a pressure balancing slit is provided between the collecting port section and the first diffuser section, the width of the pressure balancing slit being 90mm.

Optionally, the first corner section comprises a first section and a second section, an included angle between the first section and the second section is 90 °, a corner deflector is arranged in the first corner section, and an included angle between the corner deflector and the first section is 45 °.

According to a second aspect of the present disclosure, a jet noise tester is provided. The jet noise tester includes: the air inlet is communicated with the air inlet device, and the air outlet is communicated with the air outlet device.

In the embodiment of the disclosure, by arranging the jet flow part and the collecting part, the jet flow part can rectify the initial gas generated by the gas source, and then uniformly accelerate the rectified gas flow without separation, so as to obtain a flow field with the speed, uniformity and turbulence degree meeting the requirements at the gas jet port. The collecting part can timely recycle the first gas into the open direct current wind tunnel after detection is completed and carry out silencing treatment, so that noise damage of the air flow sprayed out by the air jet to the silencing chamber is avoided, backflow of the first gas in the wind tunnel body is avoided, opposite gas resistance is further generated for a jet noise test, and safety and accuracy of the test are improved.

Other features of the present utility model and its advantages will become apparent from the following detailed description of exemplary embodiments of the utility model, which proceeds with reference to the accompanying drawings.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the utility model and together with the description, serve to explain the principles of the utility model.

FIG. 1 is a schematic diagram of an open DC wind tunnel according to an embodiment of the present disclosure.

Fig. 2 is a schematic diagram of a stabilizing section according to an embodiment of the present disclosure.

FIG. 3 is a schematic illustration of a pressure balance slit according to an embodiment of the present disclosure.

Reference numerals illustrate:

1. a sound-deadening chamber; 2. an air inlet section; 21. an air inlet; 3. a stabilizing section; 31. a honeycomb device; 32. a damping net; 4. a constriction section; 5. a spout section; 51. an air jet; 6. collecting the mouth section; 61. a collection port; 7. a first diffusion section; 8. a first corner section; 81. a first section; 82. a second section; 83. corner deflectors; 9. a horizontal pipe sound attenuation section; 10. a fan section; 11. a second diffusion section; 111. an exhaust port; 12. a pressure balance slit; 13. an air intake device; 14. and an exhaust device.

Detailed Description

Various exemplary embodiments of the present utility model will now be described in detail with reference to the accompanying drawings. It should be noted that: the relative arrangement of the components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present utility model unless it is specifically stated otherwise.

The following description of at least one exemplary embodiment is merely exemplary in nature and is in no way intended to limit the utility model, its application, or uses.

Techniques, methods, and apparatus known to one of ordinary skill in the relevant art may not be discussed in detail, but are intended to be part of the specification where appropriate.

In all examples shown and discussed herein, any specific values should be construed as merely illustrative, and not a limitation. Thus, other examples of exemplary embodiments may have different values.

It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further discussion thereof is necessary in subsequent figures.

According to a first embodiment of the present disclosure, as shown in fig. 1, an open dc wind tunnel is provided. The open direct current wind tunnel comprises: a sound-deadening chamber 1, a jet part and a collecting part.

The jet part comprises an air inlet section 2, a stabilizing section 3, a contracting section 4 and a nozzle section 5 which are connected in sequence. One end of the air inlet section 2 is an air inlet 21. The air inlet 21 is in communication with an air source. At one end of the nozzle section 5 is a gas jet 51. The diameter of the stabilizing section 3 is greater than the diameter of the constriction section 4. The diameter of the convergent section 4 is greater than the diameter of the spout section 5.

The collecting part comprises a collecting port section 6, a first diffusion section 7, a first corner section 8, a horizontal pipeline silencing section 9, a fan section 10 and a second diffusion section 11 which are connected in sequence. One end of the collecting port section 6 is a collecting port 61. The collection port 61 is opposite to the gas ejection port 51. One end of the second diffusion section 11 is an exhaust port 111.

The jet flow part and the collecting part are arranged at intervals. And both the spout section 5 and the collecting port section 6 are positioned in the muffling chamber 1. Under the conditions in which the jet noise test is performed, the jet portion is configured to rectify the initial gas generated from the gas source and discharge the rectified initial gas from the gas jet port 51. The gas discharged from the gas nozzles 51 is denoted as a first gas. The collection portion is configured to collect the first gas and exhaust from the exhaust port 111.

In the embodiment of the present disclosure, by providing the jet flow portion and the collecting portion, the jet flow portion can rectify the initial gas generated by the gas source, and then uniformly accelerate the rectified gas flow without separation, and a flow field with a speed, uniformity and turbulence degree meeting requirements is obtained at the gas jet port 51. The collecting part can timely recycle the first gas into the open direct current wind tunnel after detection is completed and carry out silencing treatment, so that noise damage of the silencing chamber 1 caused by air flow sprayed out by the air jet 51 is avoided, backflow of the first gas in the wind tunnel body is avoided, opposite gas resistance is generated for jet noise test, and safety and accuracy of the test are improved.

For example, the stabilizing section 3 serves to stabilize a disturbed and uneven airflow from the outside, attenuate the vortex, and make the airflow velocity and direction distribution more uniform.

The jet section 5 is where the air flow velocity required for the test is generated. Alternatively, the jet section 5 has a diameter Φ1.6m and a length 1.6m, and the jet section 5 protrudes into the muffling chamber 1.

The present wind tunnel is an open dc wind tunnel, and the anechoic chamber 1 is a place where a model test and an acoustic test are performed. Considering the possible low-frequency flutter phenomenon of the open direct current wind tunnel during operation, which affects the quality of a flow field and a test sound field, two silencing and ventilation windows are arranged on one side of the silencing chamber 1, which is close to the air nozzle 51, and are used for balancing the pressure difference between the inside and the outside of the silencing chamber 1, inhibiting the low-frequency flutter and improving the static pressure gradient of the flow field.

In order to reduce the transmission of fan section 10 noise to the anechoic room 1, be provided with the pipeline anechoic section between first turning section 8 and fan section 10, increase the piece formula silencer in the anechoic passageway, can effectively isolate fan section 10 noise to propagate in the upstream anechoic room 1 through the air current, this department sets up the flow resistance that the anechoic piece increases simultaneously little, and it is little to the stability damage of flow field.

Optionally, the diameter phi of the pipe silencing section is 2.75m, the length is 4.0m, a guide vane type silencer is arranged inside the pipe silencing section, and the blocking degree is 40%.

In order to further reduce the exhaust losses of the open-ended straight-flow wind tunnel relatively little and to reduce the noise of the air flow, a second diffuser 11 is arranged after the fan section 10, in order to reduce the speed of the air flow to a minimum after passing through the second diffuser 11, and to convert its kinetic energy as much as possible into pressure energy close to the external atmospheric pressure, thus reducing the exhaust losses.

Alternatively, in order to prevent significant flow separation, the diffusion angle of the second diffusion section 11 is generally controlled within the range of θ=6° -8 °, while the area ratio of the second diffusion section 11 should be limited to about 2, and the exhaust speed of the dc wind tunnel outlet is generally <30m/s. In order to prevent rain, snow, insects, wind and sand and the like from entering the wind tunnel, a layer of wire mesh is arranged at the outlet of the exhaust diffusion section.

In one example, the air inlet 21 extends outwardly in an arc toward the air source.

For example, the air inlet 21 extends outwards along an arc line towards the direction of the air source, so that the air inlet section 2 and the air source can be well attached, the inflow loss is reduced to the minimum, unnecessary damage caused by leakage of air at the air inlet 21 is avoided, good rectification of the initial air source at the jet flow part can be ensured, and the accuracy of the test is improved.

Alternatively, the length of the air inlet 21 is 960mm, the arc radius of the horn-shaped air inlet 21 is 0.2 times the diameter of the stabilizing section 3, and the arc radius is 960mm.

In one example, the shrink ratio of shrink section 4 is 9.

For example, the contraction section 4 is mainly used for uniformly accelerating the rectified airflow without separation, a flow field with the speed, uniformity, turbulence and airflow deflection meeting requirements is obtained at the air nozzle 51, and in an open direct current wind tunnel, the contraction section 4 is equivalent to a spray pipe of equipment to be detected.

The dimensions of the constriction 4 mainly comprise the constriction ratio C and the constriction 4 length L _C 。

It should be noted that a larger constriction ratio is advantageous for obtaining a lower turbulence in the nozzle section 5. However, the isotropy and spectral characteristics of the turbulence of the nozzle segment 5 obtained by using a large shrinkage ratio are greatly different from those of the real flight environment, which causes the problem of inaccurate test data. In addition, the shrinkage ratio is too large, so that the investment of the tunnel body of the open direct current wind tunnel is obviously increased, and the test cost is obviously increased. In the implementation, the shrinkage ratio of the shrinkage section 4 is set to be 9, so that the lower turbulence degree can be ensured to be obtained, the actual flight environment can be more similar, and the accuracy of the test is improved.

Optionally, taking the shrinkage ratio as 9 into consideration the requirements of the quality of the convection field of the open direct current wind tunnel. The inlet section of the constriction section 4 is phi 4.8m, the outlet section size is phi 1.6m, and the length of the constriction section 4 is 4.8m.

In one example, the single-sided diffusion angle of the collection port 61 is 3 ° -5 °.

The flow field of the first gas emitted from the gas nozzle 51 may be regarded as a free jet, and the equal mass core stream has a single-sided diffusion angle α >1.5 °, and the size and shape of the collection port 61 must be designed to take into consideration the influence of this angle.

In this embodiment, the collection port 61 is sized to have a single-sided diffusion angle of 3-5. Therefore, after the detection of the first gas is completed, the first gas can be timely and furthest recycled into the open direct current wind tunnel to be subjected to silencing treatment, so that noise damage of the silencing chamber 1 caused by air flow sprayed out of the air jet opening 51 is avoided, backflow of the first gas in the wind tunnel body is avoided, opposite gas resistance is generated for a jet flow noise test, and the safety and accuracy of the test are improved.

In one example, as shown in fig. 2, a honeycomb 31 and a damping net 32 are provided in the stabilizing section 3. The honeycomb 31 is disposed at one end near the air intake port 21. The damping net 32 is disposed at an end of the honeycomb 31 near the air ejection port 51.

For example, in order to obtain a better flow field quality, a honeycomb 31 and a damping net 32 are installed in the stabilizing section 3. The main function of the honeycomb device 31 is to guide and divide the large vortex of the air flow, the honeycomb lattice structure adopts a regular hexagon, the resistance loss is small, the air flow uniformity is good, and the slenderness ratio is generally 10-15.

Preferably, the honeycomb 31 adopts regular hexagons with cells at an opposite side distance of 25mm, the depth is 300mm, and the cell slenderness ratio of the honeycomb 31 is 12.

The damping net 32 is a square hole steel wire woven net with the wire diameter of 0.3mm and 14 meshes/inch, the aperture ratio of the damping net 32 is 64%, and the distance between two layers of damping nets 32 is larger than 500 times of the wire diameter, so that the turbulence generated by an upstream layer of net is fully attenuated and then enters a downstream layer of net, and therefore, the intervals between the damping nets 32 are 480mm. The number of layers of damping mesh 32 is 5.

In one example, as shown in fig. 3, a pressure equalization slit 12 is provided between the collecting port section 6 and the first diffuser section 7. The width of the pressure equalization slit 12 is 90mm.

For example, the first gas is collected into the collection port section 6 and enters the first diffusion section 7 after being ejected out of the gas ejection port 51. The flow field generated by the first gas has low-frequency pulsation of the air flow caused by the jet flow of the opening, and obvious vibration of the air flow and the structural hole body is caused when the air flow is serious, so that the safety of the hole body is endangered.

In order to control or avoid the low-frequency pulsation of the air flow, a 90mm pressure balance slit 12 is reserved between the collecting port section 6 and the first diffusion section 7, the axial position of the collecting port section 6 is adjustable, and the pressure pulsation of the air flow near the inlet of the diffusion section is reduced by adjusting the width of the pressure balance slit 12.

The primary function of the first diffuser 7 is to restore the kinetic energy of the gas flow to pressure energy, thereby reducing the energy loss of the gas flow at the sections downstream of the diffuser.

Optionally, the diameter of the inlet of the first diffusion section 7 of the wind tunnel is phi 2.2m, the cross section of the outlet is phi 2.75m, and the length of the first diffusion section 7 is 6.5m.

In one example, the first corner section 8 includes a first section 81 and a second section 82. The angle between the first section 81 and the second section 82 is 90 °. A corner deflector 83 is provided in the first corner section 8. The corner deflector 83 is at an angle of 45 ° to the first segment 81.

For example, in order to reduce the transmission of noise of the fan section 10 upstream, a first corner section 8 is provided after the first diffuser section 7, the direction of flow of the air flow after passing through the corner section is changed by 90 °, and in order to prevent separation of the air flow, improve the flow of the air flow and reduce losses, a corner deflector 83 is provided at the corner, the corner deflector 83 having an angle of 45 ° with the first section 81.

According to a second embodiment of the present disclosure, a jet noise tester is provided. The jet noise tester includes: an air intake device 13, an air exhaust device 14 and an open direct current wind tunnel. The intake port 21 communicates with the intake device 13. The exhaust port 111 communicates with the exhaust device 14.

In the embodiment of the present disclosure, by providing the spouting portion and the collecting portion, the intake port 21 communicates with the intake device 13. The exhaust port 111 is communicated with the exhaust device 14, and the jet part can rectify the initial gas generated by the gas source, and then uniformly accelerate the rectified gas flow without separation, so as to obtain a flow field at the gas jet 51, wherein the speed, uniformity and turbulence all meet the requirements. The collecting part can timely recycle the first gas into the open direct current wind tunnel after detection is completed and carry out silencing treatment, so that noise damage of the silencing chamber 1 caused by air flow sprayed out by the air jet 51 is avoided, backflow of the first gas in the wind tunnel body is avoided, opposite gas resistance is generated for jet noise test, and safety and accuracy of the test are improved.

The foregoing embodiments mainly describe differences between the embodiments, and as long as there is no contradiction between different optimization features of the embodiments, the embodiments may be combined to form a better embodiment, and in consideration of brevity of line text, no further description is given here.

While certain specific embodiments of the utility model have been described in detail by way of example, it will be appreciated by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the utility model. It will be appreciated by those skilled in the art that modifications may be made to the above embodiments without departing from the scope and spirit of the utility model. The scope of the utility model is defined by the appended claims.

Claims

1. An open dc wind tunnel, comprising:

a sound-deadening chamber;

2. An open-ended direct current wind tunnel according to claim 1, wherein the inlet port extends outwardly in an arc in a direction towards the source of gas.

3. An open dc wind tunnel according to claim 1, wherein the shrinkage ratio of the shrinkage section is 9.

4. An open dc wind tunnel according to claim 1, wherein the single-sided spread angle of the collecting opening is 3 ° -5 °.

5. An open dc wind tunnel according to claim 1, wherein a honeycomb device is arranged in the stabilizing section, which honeycomb device is arranged at the end near the air inlet, and a damping net is arranged at the end of the honeycomb device, which is remote from the air jet.

6. An open dc wind tunnel according to claim 1, wherein a pressure balancing slit is provided between the collecting opening section and the first diffuser section, the width of the pressure balancing slit being 90mm.

7. An open dc wind tunnel according to claim 1, wherein the first corner section comprises a first section and a second section, the first section and the second section having an angle of 90 °, a corner deflector being provided in the first corner section, the corner deflector having an angle of 45 ° to the first section.

8. A jet noise tester, comprising: air inlet means, air outlet means and an open-ended direct current wind tunnel according to any of the preceding claims 1-7, said air inlet being in communication with said air inlet means and said air outlet being in communication with said air outlet means.