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Low-frequency pressure pulsation suppression method for wind tunnel 3/4 opening test section

A technology of pressure pulsation and test section, applied in the field of wind tunnel test, can solve the problems of large structure size, small effect, complex shape of resonator cavity, etc., and achieve the effect of convenient use and simple structure

Active Publication Date: 2020-11-13
LOW SPEED AERODYNAMIC INST OF CHINESE AERODYNAMIC RES & DEV CENT
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method has the following disadvantages. First, the shape of the resonator is usually complex and the size of the structure is large. Usually, it needs to be considered in the design stage of the wind tunnel, and the interface is reserved.
Second, this method can only suppress the low-frequency pressure pulsation transmitted through the cave body circuit. If the pressure pulsation is not transmitted through the circuit, such as the pulsation mode in the test chamber, this method has little effect on suppressing the pulsation.

Method used

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  • Low-frequency pressure pulsation suppression method for wind tunnel 3/4 opening test section
  • Low-frequency pressure pulsation suppression method for wind tunnel 3/4 opening test section
  • Low-frequency pressure pulsation suppression method for wind tunnel 3/4 opening test section

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Experimental program
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Effect test

Embodiment 1

[0034] Such as image 3 As shown, it is the comparison between the wind tunnel test section with wall plate and the test without wall plate installed in the wind tunnel of the 3 / 4 opening test section of this embodiment. When the wind tunnel test is carried out, the results can be obtained, and the increase After the double-wall turbulence body, the low-frequency pressure pulsation of the wind tunnel is greatly suppressed, and the peak value of the pulsation drops from 132dB in the empty wind tunnel to 112dB with the turbulence body, and the corresponding pulsation energy is reduced by 100 times.

Embodiment 2

[0036] Under the conditions of the full opening wind tunnel in the prior art, such as Figure 4 As shown, if a spoiler is used at the nozzle, if a flow guide unit is added at the nozzle, the pulse pressure amplitude can be reduced from 36.4Pa to 6.1Pa.

[0037] Combining with Example 1 for comparison, for the 3 / 4 opening test section in this example, because of the opening structure of the wind tunnel, the pulsating pressure amplitude is stronger than that of the full opening test section, so the method of adding a flow guide unit at the nozzle is adopted. The noise reduction effect of the method is limited, such as Figure 5 As shown, after adding the diversion unit at the nozzle, the peak value of low-frequency pressure fluctuations in the typical state is only reduced by about 4dB. Safety.

[0038] Therefore, in the prior art, the technical scheme of installing a flow bypass at the nozzle cannot replace the two symmetrical walls in the downstream of the test section and i...

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Abstract

The invention discloses a low-frequency pressure pulsation suppression method for a 3 / 4 opening test section of a wind tunnel. The wind tunnel is the 3 / 4 opening test section, the test section sequentially comprises a jet nozzle, a test section floor and a jet collector from one end to the other end, wherein a wall plate for inhibiting vortex development is arranged in an excitation source propagation path and a disturbance feedback loop at the downstream of the test section. The device is simple in structure, does not need to damage a wind tunnel body structure, is installed at the downstreamof a 3 / 4 opening test section, does not affect measurement of far-field noise after low-noise design and noise elimination measures are added, directly acts on a low-frequency pressure pulsation generation source, and can play a good role in restraining low-frequency pressure pulsation of different propagation paths.

Description

technical field [0001] The invention relates to the field of wind tunnel tests, in particular to a method for suppressing low-frequency pressure fluctuations in wind tunnel acoustic tests. Background technique [0002] The phenomenon of low-frequency pressure pulsation is a common phenomenon in open wind tunnels. Its typical manifestation is that within a specific wind speed range, there are strong low-frequency pressure pulsations in the jet flow and the chamber of the wind tunnel, which are similar to single-frequency characteristics. Low-frequency pressure fluctuations will not only affect the flow field quality of the open jet and the accuracy of acoustic and aerodynamic test measurements, but also cause vibration fatigue of the test equipment, affect test safety, and some even cause structural resonance in the wind tunnel chamber. endanger the safety of the entire wind tunnel building. Therefore, the low-frequency pulsation of the open-jet wind tunnel must be effective...

Claims

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Application Information

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IPC IPC(8): G01M9/04
CPCG01M9/04
Inventor 张俊龙姜裕标赵昱章荣平杨本川赵杰
Owner LOW SPEED AERODYNAMIC INST OF CHINESE AERODYNAMIC RES & DEV CENT
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