CN111929026B - Low-frequency pressure pulsation suppression method for wind tunnel 3/4 opening test section - Google Patents
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Abstract
The invention discloses a method for suppressing low-frequency pressure pulsation of an 3/4 opening test section of a wind tunnel, wherein the wind tunnel is a 3/4 opening test section, the test section sequentially comprises a jet flow nozzle, a test section floor and a jet flow collector from one end to the other end, and wall plates for suppressing vortex development are arranged in an excitation source propagation path and a disturbance feedback loop at the downstream of the test section; the invention has simple structure, does not need to damage the structure of the wind tunnel body, is arranged at the downstream of an 3/4 opening test section, does not influence the measurement of far-field noise after low-noise design and noise elimination measures, directly acts on a low-frequency pressure pulsation generating source, and can play a good role in inhibiting the low-frequency pressure pulsation of different propagation paths.
Description
Technical Field
The invention relates to the field of wind tunnel tests, in particular to a low-frequency pressure pulsation suppression method in a wind tunnel acoustic test.
Background
The phenomenon of low-frequency pressure pulsation is a phenomenon commonly existing in an open wind tunnel, and is typically represented by strong low-frequency pressure pulsation with approximate single-frequency characteristics existing in jet flow and a resident room of the wind tunnel in a specific wind speed range. The low-frequency pressure pulsation can not only influence the flow field quality of the open jet flow and the accuracy of acoustic and aerodynamic test measurement, but also cause vibration fatigue of test equipment, influence the test safety, and even cause structural resonance of a wind tunnel parking chamber to endanger the safety of the whole wind tunnel building. Therefore, it is necessary to effectively suppress the low frequency pulsation of the open jet wind tunnel.
The wind tunnel needs to comprise an excitation source and a feedback loop to generate a strong low-frequency pressure pulsation phenomenon similar to a single frequency. It is generally believed that the excitation is primarily due to the impact of large-scale unsteady vortices in the shear layer of the wind tunnel jet with the collector. After the shear layer vortex hits the collector, a strong pressure disturbance is generated, which propagates at the speed of sound. When the disturbance is transmitted to the wind tunnel nozzle, new vortex shedding can be caused, so that a whole feedback loop is formed, the disturbance is circulated in such a way, and the disturbance is gradually enhanced to form a strong pressure pulsation phenomenon.
At present, two measures for inhibiting the low-frequency pressure pulsation of the opening jet flow are mainly adopted at home and abroad. One is to add a vortex generator at the jet nozzle to promote the rapid transition of the jet boundary into turbulent flow, such as in the patent publication (CN 201710855108.2). The turbulent boundary layer has an inhibiting effect on the formation of a large-scale structure, so that the low-frequency pressure pulsation of a test section can be inhibited to a certain extent. The method has the disadvantages that the turbulent jet boundary after transition has higher flow mixing efficiency and higher jet boundary expansion speed, so that the area of a laminar flow core part which can be used for a test is reduced, and sound source positioning of a far-field microphone array is influenced after the jet shear layer is disordered. Another approach is to construct resonant cavities in wind tunnel cavities, such as that disclosed in the published patent (CN 201810330249.7), for damping low frequency pressure pulsations transmitted through the cavity circuit. The method has the following defects that firstly, the resonant cavity is complex in appearance and large in structural size, and an interface is reserved in consideration of the design stage of the wind tunnel. Secondly, the method can only inhibit the low-frequency pressure pulsation transmitted through the hole body loop, and if the pressure pulsation is not transmitted through the loop, such as the pulsation mode in a laboratory, the effect of the method on inhibiting the pulsation is not large.
Disclosure of Invention
The invention aims to provide a low-frequency pressure pulsation suppression method, which directly acts on a shear layer to suppress the development of large-scale vortices in the shear layer, so as to effectively reduce the strength of the vortices impacting with a collector and further suppress the low-frequency pressure pulsation of a wind tunnel.
In order to achieve the purpose, the invention adopts the following technical scheme:
the utility model provides a be used for wind-tunnel 3/4 opening test section low frequency pressure pulsation suppression method, the wind-tunnel is 3/4 opening test section, and the test section includes efflux spout, test section floor and efflux collector from one end to the other end in proper order, is provided with the wallboard that is used for suppressing vortex development in excitation source propagation path and the disturbance feedback loop of test section low reaches.
In the technical scheme, the wall plate is arranged in the jet flow shearing layer area.
In the technical scheme, one end of the wall plate is fixedly connected to the floor of the test section.
Among the above-mentioned technical scheme, including two blocks of wallboard, two blocks of wallboards set up along efflux direction symmetry.
In the above technical solution, the wall plate is of an airfoil structure, and the airfoil leading edge is swept backward in the spanwise direction to reduce upstream propagation of pressure pulsation caused by vortex impact.
In the technical scheme, the wallboard comprises an airfoil framework, a sound absorption material filled in the airfoil framework, a perforated plate laid on the surface of the airfoil framework and a sound-transmitting cotton felt laid on the surface of the perforated plate.
The invention also discloses an application of the low-frequency pressure pulsation suppression method for the wind tunnel 3/4 opening test section.
Preferably, the method is applied to an established wind tunnel or a newly-built wind tunnel.
Preferably, the method is used in an already built wind tunnel without a resonant cavity.
The working principle of the invention is as follows: the low-frequency pressure pulsation of the wind tunnel is closely related to the large-scale unstable vortex in the jet flow shear layer of the wind tunnel. As the jet shear layer expands downstream in the wind tunnel, the intensity of the unstable vortices in the shear layer gradually increases. When a strong unstable vortex structure collides with the jet collector, the vortex breaks to generate strong pulsation which propagates upstream to modulate the separation of the vortex in the shear layer near the nozzle, thereby forming a feedback loop to cause strong low-frequency pressure pulsation. The invention adds a flow disturbing wall plate device on the floor of the test section in front of the jet flow collector, and the device is positioned on the propagation path of the jet flow shear layer. On one hand, the growth of large-scale unstable vortexes in the jet flow shear layer is prevented, on the other hand, the formed unstable vortexes are destroyed, so that the unstable vortexes are broken in advance, the orderly impact of the vortexes and the collector is prevented, and further, the generation of low-frequency pressure pulsation is prevented from the source.
In summary, due to the adoption of the technical scheme, the invention has the beneficial effects that:
1. because the low-frequency pressure pulsation suppression device directly acts on a low-frequency pressure pulsation generation source, the suppression device can play a good role in suppressing the low-frequency pressure pulsation of different propagation paths.
2. The wind tunnel body structure is simple in structure, free of damage to the wind tunnel body structure and convenient to use.
3. The device is arranged at the downstream of an 3/4 opening test section, and the measurement of far-field noise is not influenced after low-noise design and noise elimination measures are added.
Drawings
The invention will now be described, by way of example, with reference to the accompanying drawings, in which:
FIG. 1 is a schematic structural view of the present invention;
FIG. 2 is a schematic view of the jet direction of the present invention;
FIG. 3 is a graph comparing the low frequency pressure pulsation suppression effect of the present invention;
FIG. 4 is a graph comparing the effect of low frequency pressure pulsation suppression using turbulators at the nozzle under full opening wind tunnel conditions;
FIG. 5 is a graph comparing the effect of low frequency pressure pulsation suppression of the addition of flow directing elements at the nozzle under 3/4 opening wind tunnel conditions;
wherein: 1 is an opening jet flow nozzle, 2 is an opening jet flow collector, 3 is 3/4 opening test section floor, 4 is a rear double-wall plate vibration suppression device, and 5 is an opening jet flow shear layer and a large-scale vortex.
Detailed Description
All of the features disclosed in this specification, or all of the steps in any method or process so disclosed, may be combined in any combination, except combinations of features and/or steps that are mutually exclusive.
Any feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving equivalent or similar purposes, unless expressly stated otherwise. That is, unless expressly stated otherwise, each feature is only an example of a generic series of equivalent or similar features.
As shown in fig. 1 and fig. 2, this embodiment is used for an 3/4 opening test segment, the test segment is an existing wind tunnel structure, or a newly-built wind tunnel structure may be adopted, and a resonant cavity may be built on a wind tunnel body, or a resonant cavity may not be built on the wind tunnel body.
In this example, to achieve low frequency pressure pulsation suppression, the core is to provide two symmetrical panels in the region of the jet shear layer downstream of the 3/4 opening test section. The wall plate is arranged on a transmission and feedback loop of an excitation source, the structure of the wall plate is utilized to inhibit the development of airflow vortexes in the transmission direction, and the impact strength of the airflow vortexes and a collector is reduced, so that the low-frequency pressure pulsation of the wind tunnel is inhibited.
In this embodiment, the wall panel employs a streamlined configuration of the airfoil to reduce self-generated noise, while the airfoil leading edge is swept aft in span-wise direction to reduce upstream propagation of pressure pulsations caused by vortex impingement. The integral structure of the wing panel is a sweepback wing panel structure. The outer layer of the device adopts a sound-transmitting composite structure of sound-transmitting cotton felt and a perforated plate, the inside of the device is an airfoil-shaped framework, and the middle of the device is filled with sound-absorbing materials. The wing-shaped sweepback structure can reduce the self-noise of the rear double-wall plate device, weaken the impact strength of large-scale vortices on the shear layer and control the feedback direction of pressure pulsation. The sound absorbing structure reduces the acoustic reflection of the device to target noise, reducing the impact on acoustic measurements.
Example one
As shown in fig. 3, compared with the experiment that the wind tunnel test section with the wallboard is added to the wind tunnel at the 3/4 opening test section in the embodiment, when the wind tunnel test is performed, the result can be obtained, after the double-wallboard disturbing fluid is added, the low-frequency pressure pulsation of the wind tunnel is greatly suppressed, the pulsation peak value is reduced from 132dB of the air tunnel to 112dB after the disturbing fluid is added, and the corresponding pulsation energy is reduced by 100 times.
Example two
Under the condition of a full-opening wind tunnel in the prior art, as shown in fig. 4, a spoiler is adopted at a nozzle, and if a flow guide unit is added at the nozzle, the pulsating pressure amplitude can be reduced from 36.4Pa to 6.1 Pa.
Compared with the first embodiment, for the 3/4 opening test section aimed in the first embodiment, because the opening structure of the wind tunnel makes the pulsating pressure amplitude stronger than that of the full opening test section, the noise reduction effect achieved by the method of adding the flow guide unit to the nozzle is limited, as shown in fig. 5, after the flow guide unit is added to the nozzle, the reduction of the low-frequency pressure pulsation peak value in a typical state is only about 4dB, at this time, the wind tunnel still has strong low-frequency pressure pulsation energy, and the safety of the wind tunnel experiment can be ensured by adopting further noise reduction measures.
Therefore, in the technical scheme of arranging the flow winder at the nozzle in the prior art, the 3/4-opening test section wind tunnel cannot replace two symmetrical wall plates arranged at the downstream of the test section and in the region of the jet flow shearing layer in the embodiment, so that the pressure pulsation can be restrained.
The invention is not limited to the foregoing embodiments. The invention extends to any novel feature or any novel combination of features disclosed in this specification and any novel method or process steps or any novel combination of features disclosed.
Claims (6)
1. A low-frequency pressure pulsation suppression method for a 3/4 opening test section of a wind tunnel is a 3/4 opening test section, the test section sequentially comprises a jet flow nozzle, a test section floor and a jet flow collector from one end to the other end, and the method is characterized in that a wallboard for suppressing vortex development is arranged in an excitation source propagation path and a disturbance feedback loop at the downstream of the test section.
2. The method for suppressing the low-frequency pressure pulsation in the opening test section of the wind tunnel 3/4 of claim 1, wherein the wall plate is arranged in a region of a jet flow shearing layer.
3. The method for suppressing low frequency pressure pulsations in an open test section of a wind tunnel 3/4 as defined in claim 2, wherein one end of said wall panel is fixedly connected to the floor of the test section.
4. The method for suppressing the low-frequency pressure pulsation in the opening test section of the wind tunnel 3/4 as claimed in claim 3, wherein the method comprises two wall plates, and the two wall plates are symmetrically arranged along the jet flow direction.
5. The method for suppressing the low-frequency pressure pulsation in the opening test section of the wind tunnel 3/4 as claimed in claim 1, wherein the wall plate is of an airfoil structure, and the leading edge of the airfoil is swept backward in the spanwise direction to reduce the upstream propagation of the pressure pulsation caused by the impact of the vortex.
6. The method for suppressing the low-frequency pressure pulsation in the opening test section of the wind tunnel 3/4 as claimed in claim 5, wherein the wall plate comprises an airfoil framework, a sound absorption material filled in the airfoil framework, a perforated plate laid on the surface of the airfoil framework and a sound-permeable cotton felt laid on the surface of the perforated plate.
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Citations (20)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3148336C2 (en) * | 1981-12-07 | 1985-03-21 | ANT Nachrichtentechnik GmbH, 7150 Backnang | Circuit arrangement for evaluating a noise signal occurring in a message receiving system |
| US5303882A (en) * | 1993-02-22 | 1994-04-19 | The United States Of America As Represented By The Secretary Of The Navy | Corner vortex suppressor |
| JP2002228542A (en) * | 2001-01-29 | 2002-08-14 | Kawasaki Heavy Ind Ltd | Air current blowing device |
| CN2927023Y (en) * | 2006-06-22 | 2007-07-25 | 同济大学 | Low-speed pneumatic opening structure |
| CN101067584A (en) * | 2007-06-14 | 2007-11-07 | 同济大学 | Opening back-flowing suppressing low-speed wind tunnel low-frequency buffeting ejector structure |
| CN101071091A (en) * | 2007-06-14 | 2007-11-14 | 同济大学 | Low frequency flutter suppression structure for open closed-circuit pneumatic-acoustic wind tunnel |
| CN201060095Y (en) * | 2007-06-14 | 2008-05-14 | 同济大学 | Collecting mouth for inhibiting opening return-flow wind tunnel low frequency oscillation |
| JP2014105482A (en) * | 2012-11-27 | 2014-06-09 | Kajima Corp | Active silencing device |
| CN105756981A (en) * | 2016-04-26 | 2016-07-13 | 浙江理工大学 | Noise reduction fan wall for shell-free centrifugal fan |
| CN106092420A (en) * | 2016-05-26 | 2016-11-09 | 中国人民解放军63820部队吸气式高超声速技术研究中心 | The method indirectly measuring electromotor effective push |
| CN106404340A (en) * | 2016-12-19 | 2017-02-15 | 大友（苏州）风洞技术有限公司 | Wind tunnel collecting port |
| CN107941450A (en) * | 2017-09-20 | 2018-04-20 | 中国空气动力研究与发展中心低速空气动力研究所 | A kind of spout angle eddy generator for suppressing the low frequency pulsation of opening jet stream wind-tunnel |
| CN108344555A (en) * | 2018-04-13 | 2018-07-31 | 中国空气动力研究与发展中心低速空气动力研究所 | A kind of anechoic room inhibiting the low frequency pulsation of opening jet stream wind-tunnel far field |
| CN109605720A (en) * | 2018-04-21 | 2019-04-12 | 广东金明精机股份有限公司 | Plastic film blowing machine inner-cooling structure |
| CN109827739A (en) * | 2019-04-02 | 2019-05-31 | 重庆科技学院 | Wind tunnel test is stretched disturbing flow device |
| CN109883641A (en) * | 2019-04-02 | 2019-06-14 | 重庆科技学院 | Wedge disturbing flow device wind field spoiler mounting structure |
| CN110040235A (en) * | 2019-05-05 | 2019-07-23 | 中国人民解放军国防科技大学 | Active and passive combined flow control method and device |
| CN110186638A (en) * | 2019-04-17 | 2019-08-30 | 中国空气动力研究与发展中心低速空气动力研究所 | A kind of sound wave passes through the device and experimental method of the sound field distortion performance test of vortex |
| CN110412315A (en) * | 2019-08-07 | 2019-11-05 | 中国气象局气象探测中心 | Integral-type wind element calibrating installation |
| CN110529287A (en) * | 2019-08-13 | 2019-12-03 | 中国航发贵阳发动机设计研究所 | A kind of combination in series punching engine fan splitter |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH08303397A (en) * | 1995-05-10 | 1996-11-19 | Hitachi Ltd | Blower device with silencer |
| JPH09159571A (en) * | 1995-12-08 | 1997-06-20 | Mitsubishi Heavy Ind Ltd | Wind direction variation device for wind tunnel |
-
2020
- 2020-09-29 CN CN202011053759.8A patent/CN111929026B/en active Active
Patent Citations (20)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3148336C2 (en) * | 1981-12-07 | 1985-03-21 | ANT Nachrichtentechnik GmbH, 7150 Backnang | Circuit arrangement for evaluating a noise signal occurring in a message receiving system |
| US5303882A (en) * | 1993-02-22 | 1994-04-19 | The United States Of America As Represented By The Secretary Of The Navy | Corner vortex suppressor |
| JP2002228542A (en) * | 2001-01-29 | 2002-08-14 | Kawasaki Heavy Ind Ltd | Air current blowing device |
| CN2927023Y (en) * | 2006-06-22 | 2007-07-25 | 同济大学 | Low-speed pneumatic opening structure |
| CN101067584A (en) * | 2007-06-14 | 2007-11-07 | 同济大学 | Opening back-flowing suppressing low-speed wind tunnel low-frequency buffeting ejector structure |
| CN101071091A (en) * | 2007-06-14 | 2007-11-14 | 同济大学 | Low frequency flutter suppression structure for open closed-circuit pneumatic-acoustic wind tunnel |
| CN201060095Y (en) * | 2007-06-14 | 2008-05-14 | 同济大学 | Collecting mouth for inhibiting opening return-flow wind tunnel low frequency oscillation |
| JP2014105482A (en) * | 2012-11-27 | 2014-06-09 | Kajima Corp | Active silencing device |
| CN105756981A (en) * | 2016-04-26 | 2016-07-13 | 浙江理工大学 | Noise reduction fan wall for shell-free centrifugal fan |
| CN106092420A (en) * | 2016-05-26 | 2016-11-09 | 中国人民解放军63820部队吸气式高超声速技术研究中心 | The method indirectly measuring electromotor effective push |
| CN106404340A (en) * | 2016-12-19 | 2017-02-15 | 大友（苏州）风洞技术有限公司 | Wind tunnel collecting port |
| CN107941450A (en) * | 2017-09-20 | 2018-04-20 | 中国空气动力研究与发展中心低速空气动力研究所 | A kind of spout angle eddy generator for suppressing the low frequency pulsation of opening jet stream wind-tunnel |
| CN108344555A (en) * | 2018-04-13 | 2018-07-31 | 中国空气动力研究与发展中心低速空气动力研究所 | A kind of anechoic room inhibiting the low frequency pulsation of opening jet stream wind-tunnel far field |
| CN109605720A (en) * | 2018-04-21 | 2019-04-12 | 广东金明精机股份有限公司 | Plastic film blowing machine inner-cooling structure |
| CN109827739A (en) * | 2019-04-02 | 2019-05-31 | 重庆科技学院 | Wind tunnel test is stretched disturbing flow device |
| CN109883641A (en) * | 2019-04-02 | 2019-06-14 | 重庆科技学院 | Wedge disturbing flow device wind field spoiler mounting structure |
| CN110186638A (en) * | 2019-04-17 | 2019-08-30 | 中国空气动力研究与发展中心低速空气动力研究所 | A kind of sound wave passes through the device and experimental method of the sound field distortion performance test of vortex |
| CN110040235A (en) * | 2019-05-05 | 2019-07-23 | 中国人民解放军国防科技大学 | Active and passive combined flow control method and device |
| CN110412315A (en) * | 2019-08-07 | 2019-11-05 | 中国气象局气象探测中心 | Integral-type wind element calibrating installation |
| CN110529287A (en) * | 2019-08-13 | 2019-12-03 | 中国航发贵阳发动机设计研究所 | A kind of combination in series punching engine fan splitter |
Non-Patent Citations (4)
| Title |
|---|
| "Reduction of 3/4 open jet low-frequency fluctuations in the S2A wind tunne";Amandolese X et al;《Journal of Wind Engineering and Industrial Aerodynamics》;20101231;全文 * |
| "收集口喉部间隙对汽车风洞低频颤振抑制作用的机理研究";郑志强等;《汽车工程》;20080925;全文 * |
| "汽车风洞试验段非定常流场的试验";贾青等;《同济大学学报(自然科学版)》;20120115;全文 * |
| "涡流发生器对3/4汽车模型风洞流场品质的影响";贾青等;《同济大学学报(自然科学版)》;20140611;全文 * |
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