CN106996204B - An anechoic chamber for the aerodynamic noise test of the fan booster stage - Google Patents

Abstract

The invention discloses an anechoic chamber used for the aerodynamic noise test of a fan booster stage, belonging to the field of anechoic chamber design. The anechoic chamber has an asymmetrical structure. The adjacent wall of one corner of the anechoic chamber is offset inwardly. The wall of the offset part is vertical, and the wall connected to it is inclined. The inner side of the vertical wall is The fan booster test piece is installed, and the inner and outer culvert exhaust systems and testers are arranged on the outside of the wall, and the distance away from the entrance of the fan booster test piece is not less than 15 times the diameter of the fan booster test piece. Far-field microphone array; the turbulence control screen is set in the direction of the windward side of the fan booster test piece, the air intake system is connected to the air inlet of the anechoic chamber, and the internal and external exhaust systems are connected to the anechoic test piece through the fan booster stage. The chamber is connected, and the tester is connected with the fan supercharging stage test piece. The present invention realizes the conditions required to be satisfied in the engineering-level fan supercharging stage noise test research.

Description

An anechoic chamber for the aerodynamic noise test of the fan booster stage

technical field

The invention belongs to the technical field of anechoic chambers, and in particular relates to an anechoic chamber used for the aerodynamic noise test of a fan supercharging stage.

Background technique

As one of the main noise sources of the aircraft, the fan supercharger test piece is a necessary means to test the low noise design and noise reduction effect of the fan supercharger, and it is also an important link in the engine noise test research system.

At present, there are only 3-4 laboratories for the experimental research on the mechanism of fan aerodynamic noise that have been built or are currently under construction in China, and the foundation is very weak; The size of the acoustic room is relatively small (the height is generally less than 7m, the length and width are less than 10m), and only basic and qualitative experimental research on the generation, propagation and suppression of single-stage fan noise sources can be carried out, which cannot meet the needs of large anechoic chambers (fan diameters are generally larger than 0.8m, anechoic chamber height greater than 8m, length and width greater than 20m) test verification requirements.

The existing anechoic chamber design method applied to the large-scale anechoic chamber design of the fan booster stage aerodynamic noise test will have the following defects:

1) The lack of consideration of the symmetry of the sound field and the corresponding special design method in the prior art will lead to a huge building area and extremely high cost;

2) There is a lack of special vibration isolation design technology for large-scale, high-power, and complex testers in the prior art, and there will be technical difficulties in ensuring good sound and vibration quality of large-scale anechoic chambers;

3) The lack of large-span roof design and anechoic wedge installation technology in the prior art will lead to difficulties in the design of large-scale anechoic chambers. Due to the demand for a fully free sound field, the anechoic chamber needs no column support structure, coupled with the self-weight of a large number of roofs and wedges, which brings difficulties to the design of the roof structure of a large-area anechoic chamber;

4) In the prior art, there is a lack of consideration of high-frequency sound waves being affected by air absorption and temperature and humidity. When the size of the anechoic chamber becomes larger, the propagation path will become longer, and the noise is affected by air absorption and temperature and humidity. The accuracy of the noise test is reduced or even the test data cannot be used;

5) Since most of the existing anechoic chambers are closed structures or there is little air circulation, there is no need to consider designing a dedicated low-noise intake tower during design. Therefore, the prior art lacks an air intake system design method suitable for open type, large air flow, high noise reduction effect, and low noise reflection, which cannot support the design of large anechoic chambers;

6) There is a lack of means to control the temperature gradient in the anechoic chamber in the prior art, and it is impossible to avoid the influence of the internal temperature gradient change on the noise test after the size of the anechoic chamber becomes larger;

7) There is a lack of methods for controlling intake turbulence in the prior art, and it is impossible to avoid that after the size of the anechoic chamber becomes larger, the interior of the anechoic chamber will be air-intaked from the ground and there will be objective intake turbulence, and it is impossible to simulate the intake conditions of the engine in high-altitude flight , and then lead to the existence of secondary noise sources, resulting in errors in test results;

8) There is a lack of a low-noise reflection microphone bracket and a high positioning accuracy method suitable for use in a high-frequency noise test environment, which cannot meet the noise test requirements of a large anechoic chamber with a frequency range of 20k-40kHz. As the size of the anechoic chamber increases, how to accurately arrange the sensors and ensure low reflection effects is a key technology that must be accumulated in the construction of a large anechoic chamber.

9) There is a lack of testing methods for the sound absorption performance of the anechoic wedge and the full anechoic chamber at frequencies above 20kHz, which cannot meet the precise testing requirements for the noise of full-scale or scaled-down fan supercharger components.

Contents of the invention

Purpose of the present invention: In order to solve the above-mentioned problems, the present invention proposes a kind of anechoic chamber that is used for the aerodynamic noise test of fan supercharging stage, and anechoic chamber adopts asymmetric layout and large-span steel-concrete structure roof design, and tester adopts Vibration isolation design, air intake system adopts open and low noise reflection design, temperature and humidity gradient influence control adopts roof insulation design and real-time monitoring design, test bracket adopts high positioning accuracy and low noise reflection design, high frequency verification adopts self-developed The verification system and verification technology meet the noise test requirements of large anechoic chambers.

The technical solution of the present invention: an anechoic chamber for fan supercharging stage aerodynamic noise test, including: tester, internal and external culvert exhaust system, air intake system, turbulence control panel;

The anechoic chamber has an asymmetric structure, and two adjacent walls at one corner of the anechoic chamber are offset toward the direction of the anechoic chamber to form an installation space, and a fan is installed on the inside of one of the offset two adjacent walls For the supercharged test piece, the inner and outer culvert exhaust systems and testers are arranged on the outside of the wall, and a far-field microphone array is arranged at the entrance of the test piece away from the fan booster stage. The far-field microphone array is far away from the fan booster stage. The distance at the entrance of the test piece is not less than 15 times the diameter of the fan booster stage test piece; the turbulence control screen is arranged at the entrance of the fan booster stage test piece to control the The inlet flow field is rectified to control the inlet distortion of the inlet flow field and suppress the problem of "extra" noise;

The tester, inner and outer culvert exhaust systems, and fan booster stage test pieces are arranged along the same axis, and the axes of each system are kept consistent;

The air intake system is connected to the air inlet of the anechoic chamber, the inner and outer culvert exhaust systems are connected to the fan booster stage test piece, the fan booster stage test piece is located in the anechoic chamber, and the tester passes through the inner , The transmission shaft in the external culvert exhaust system is connected to the fan supercharging stage test piece to provide power for it;

The inner and outer culvert exhaust systems and the tester are separated from the anechoic chamber by walls. The walls of the anechoic chamber are double-layered walls, and cavities are reserved between the walls or filled with radiation. Sound-absorbing material, the central height of the anechoic chamber is set to 5-8 times the diameter of the fan pressurized stage test piece;

The far-field microphone array is evenly distributed in an arc shape centered on the inlet of the fan booster stage test piece, the angular interval between each microphone is not more than 5°, and the test angle range is 5°-120°, and the The distance from the far-field microphone array to the wall of the anechoic chamber is not less than 3m;

An anechoic wedge is installed in the anechoic chamber, the cut-off frequency of the anechoic wedge is more than 70% of the lowest frequency of the test noise in the anechoic chamber, and the sound absorption coefficient of the anechoic wedge is within the frequency range of the tested noise Not less than 0.99.

Preferably, the roof of the anechoic chamber is provided with a large-span self-supporting steel frame support structure, the top of the support structure is provided with a protection structure, and the protection structure is connected to the support structure through a triangular interactive connection structure, so The lower surface of the supporting structure is equipped with sound-absorbing wedges;

The protection structure includes: a shale protection layer, a polyester tire belt protection layer, a leveling layer and a hydrophobic perlite insulation layer arranged from top to bottom to avoid temperature gradients inside the anechoic chamber due to direct sunlight.

Preferably, the inner and outer bypass exhaust systems are composed of an inner duct, an outer duct and an exhaust muffler tower, the rear ends of the inner duct and the outer duct are connected to the exhaust muffler tower, and the inner duct It is connected with the front end of the external duct and the fan supercharging stage test piece;

Preferably, the tester is composed of a motor, a gearbox and a torsion shaft, and the tester is connected to the fan supercharging stage test piece through the torsion shaft and the transmission shaft, and the motor, the gearbox, and the torsion shaft are connected in sequence, and the common Set on the same concrete platform, which is isolated from the anechoic chamber;

The concrete platform is composed of an upper foundation, a lower foundation and a damping pad between them.

Preferably, the air intake system is composed of an air intake guide device and an air intake muffler tower;

The air intake diversion device is arranged in the air intake muffler tower, and the air intake muffler tower is provided with an air intake device, a filter device and a muffler, and the air flow enters the filter device and the muffler successively through the air intake device, and passes through the inlet muffler. The air guide device enters the anechoic chamber;

The filter device is set in the air intake device and is composed of air intake louvers, stainless steel protective net, electric rolling door and G4 grade filter;

The stainless steel protective net is close to the outside of the air inlet of the air intake device, the G4 grade filter is arranged on the inner side of the air inlet of the air intake device, and the air intake louvers are arranged on the stainless steel protective net far away from the air inlet. One side of the G4 grade filter, the electric rolling door is set on the side of the G4 grade filter close to the stainless steel protective net;

A closed cavity is set between the stainless steel protective net and the G4 grade filter, and a monitoring device is set in the closed cavity.

Preferably, the turbulence control screen is composed of a turbulence control unit, which is used to solve the problem that the ground noise test results cannot reflect the noise in the air flight state due to the large intake turbulence in the ground noise test process; on the other hand, it is used to solve the problem of using After the layout design of the asymmetrical anechoic chamber, the problem of asymmetrical intake airflow field, further increase of intake turbulence and "extra" noise is generated.

Preferably, temperature and humidity detection points are set inside the anechoic chamber, and the temperature and humidity detection points are distributed at six points for temperature and humidity detection and temperature gradient monitoring;

The selection of the temperature and humidity detection points is based on the calculation results of the CFD flow field, centered on the fan supercharging stage test piece, and three different radii and two different angles are evenly distributed, which can detect the high-frequency sound waves absorbed by the air. Analysis of the influence of temperature and humidity can solve the technical problem that the noise is affected by air absorption and temperature and humidity when the size of the anechoic chamber is enlarged, which leads to inaccurate noise testing.

Preferably, the anechoic chamber also includes an anechoic wedge and an acoustic characteristic detection system of the anechoic chamber;

The acoustic characteristic detection system of the anechoic wedge and the anechoic chamber includes: a medium-high frequency sound source, an acoustic waveguide, a test bracket, a microphone, a guy wire, a data acquisition device and a control device;

When testing the acoustic characteristics of the anechoic chamber, it is necessary to connect the acoustic waveguide through the anechoic chamber to the medium-high frequency sound source, and the installation axis of the acoustic waveguide is at the same height as the centerline of the anechoic chamber. The medium and high frequency sound source transmits sound waves to the anechoic chamber through the sound waveguide; when the radiation sound field of the medium and high frequency sound source has good uniform characteristics, the medium and high frequency sound source can be directly placed in the anechoic chamber without using the sound waveguide Indoor, and make the medium and high frequency sound source installation axis be at the same height as the center line of the anechoic chamber to be inspected, and the medium and high frequency sound source directly transmits sound waves to the anechoic chamber;

When testing the acoustic characteristics of the anechoic wedge, it is necessary to connect the acoustic waveguide through the anechoic chamber to the medium-high frequency sound source, and the installation axis of the acoustic waveguide is located at the center line of the anechoic wedge and the anechoic chamber. At the same height, the middle and high frequency sound source transmits sound waves to the anechoic chamber through the sound waveguide; when the radiation sound field of the middle and high frequency sound source has good uniform characteristics, the sound waveguide can not be used, and the middle and high frequency sound source can be directly placed in the anechoic chamber In the room, and make the installation axis of the medium and high frequency sound source be at the same height as the anechoic wedge sample to be tested and the center line of the anechoic chamber, and the medium and high frequency sound source directly transmits sound waves to the anechoic chamber;

The test bracket is arranged between the acoustic waveguide and the wedge sample or the anechoic chamber, the microphone and the data acquisition device are installed at the front end of the test bracket, and the test bracket is controlled by the control device, movable along the guy wire between the wedge sample or the anechoic chamber and the acoustic waveguide;

The acoustic characteristic detection system of the anechoic wedge and the anechoic chamber can obtain the attenuation change characteristics of the sound pressure on the propagation path with the propagation distance. By comparing the curves, the sound absorption characteristics of the sound-absorbing wedge in the middle and high-frequency bands can be obtained.

Preferably, the test bracket includes a sensor bracket, a lifting measuring head, and a laser positioner, and the sensor bracket is composed of a base, a lower pole, an upper pole, a pulley cable structure and industrial universal casters;

The base is square, and the four bottom corners are respectively installed with industrial universal casters. The base is vertically installed with a lower pole and an upper pole from the bottom to the top. A laser positioner and a lifting measuring head are arranged in the direction of the axis of the upper pole.

Technical effects of the present invention: On the basis of the traditional anechoic chamber design, the present invention aims at the uniqueness of the design of the large anechoic chamber required for the aeroacoustic test of the original scale or scaled fan booster stage test piece, and comprehensively considers the economy In order to meet the requirements of usability and usability, a proprietary design is carried out in terms of shape and size, sound and vibration quality control, temperature and humidity data influence and correction, intake turbulence control, and low-noise intake tower design, forming an aerodynamic noise for fan booster stage. A large anechoic chamber for experiments.

Description of drawings

Fig. 1 is a structural representation of a preferred embodiment of an anechoic chamber used for fan supercharging stage aerodynamic noise test of the present invention;

Fig. 2 is a schematic diagram of the large-span self-supporting steel frame support structure of the anechoic chamber of the embodiment shown in Fig. 1;

Fig. 3 is the schematic diagram of the vibration isolation design of the tester of the embodiment shown in Fig. 1;

Fig. 4 is the design schematic diagram of the intake system of the embodiment shown in Fig. 1;

Fig. 5 is a schematic structural view of the filtering device of the embodiment shown in Fig. 4;

Fig. 6 is a structural schematic diagram of a preferred embodiment of an anechoic wedge and an anechoic chamber acoustic characteristic detection system for an anechoic chamber used in fan supercharging stage aerodynamic noise tests;

Among them, 1-Anechoic chamber, 2-Intake system, 3-Far-field microphone array, 4-Anechoic wedge, 5-Turbulence control screen, 6-Fan booster test piece, 7-Motor, 8-Gear Box, 9-torsion shaft, 10-outer duct, 11-exhaust muffler tower, 12-inner duct, 13-support structure, 14-protection structure, 15-triangular interactive connection structure, 16-upper foundation, 17 -Lower foundation, 18-vibration damping pad, 19-intake air guide device, 20-intake muffler tower, 21-intake device, 22-muffler, 23-intake louver, 24-stainless steel protective net, 25- Electric rolling shutter, 26-G4 level filter, 27-monitoring device, 28-medium and high frequency sound source, 29-acoustic waveguide, 30-test bracket, 31-microphone, 32-guy wire, 33-data acquisition device, 34-control device.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be described in more detail below in conjunction with the drawings in the embodiments of the present invention. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are some, but not all, embodiments of the invention. The embodiments described below by referring to the figures are exemplary and are intended to explain the present invention and should not be construed as limiting the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention. Embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings.

In describing the present invention, it is to be understood that the terms "central", "longitudinal", "transverse", "front", "rear", "left", "right", "vertical", "horizontal", The orientations or positional relationships indicated by "top", "bottom", "inner", "outer", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying the Means that a device or element must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be construed as limiting the scope of the invention.

Embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, please refer to Figures 1 to 6;

An anechoic chamber for the aerodynamic noise test of the fan booster stage, including: a tester, an inner and outer exhaust system, an air intake system 2, and a turbulence control panel 5;

The anechoic chamber 1 has an asymmetrical structure. Two adjacent walls at one corner of the anechoic chamber are offset toward the direction of the anechoic chamber. One of the walls in the offset part is vertical, and the other wall connected to it is inclined. , to form an installation space, install the fan booster stage test piece 6 on the inside of the vertical wall, and set the inner and outer culvert exhaust systems and testers on the outside of the wall. The anechoic chamber 1 adopts an asymmetric structure design, which solves the problem of large The problem of large construction area of the anechoic chamber saves the construction area of the anechoic chamber to the greatest extent and saves costs.

The wall of the anechoic chamber 1 is a double-layer wall structure, and cavities are reserved between the walls or filled with sound-absorbing materials to ensure sufficient sound insulation and vibration isolation effects of the walls.

Based on the principle of sound field symmetry, the axis of the exhaust system of the inner and outer culverts is placed on one side of the anechoic chamber, and is located on the central elevation plane of the anechoic chamber. Keep a large distance between the intake and exhaust axis and the center line of the anechoic chamber to save the construction area of the anechoic chamber to the greatest extent, but the influence of factors such as intake turbulence control, the distance between the intake and exhaust axis and the wall of the anechoic chamber must be considered. Ensure that the noise data tested in the anechoic chamber is not affected by spatial asymmetry.

The height of the anechoic chamber should comprehensively consider the inlet diameter of the fan booster stage test piece, so that the noise transmitted before the fan will not cause sound field distortion due to the small height of the anechoic chamber. The center height of the anechoic chamber is 5-5- 8 times, in this embodiment, the central height of the anechoic chamber is preferably 8 times the diameter of the test piece.

The tester, inner and outer culvert exhaust systems, and fan booster stage test pieces 6 are arranged along the axis one by one. The thick walls are used for isolation, supplemented by other sound insulation and vibration isolation measures, so as to prevent the operating noise of the tester from entering the anechoic room to the greatest extent.

The tester is composed of a motor 7, a gearbox 8 and a torsion shaft 9, and the tester is connected to the fan booster stage test piece 6 through the torsion shaft 9, and the motor 7, the gearbox 8, the torsion shaft 9 and the exhaust volute are connected in sequence, They are set together on the same concrete platform. The concrete platform is composed of the upper foundation 16, the lower foundation 17 and the vibration damping pad 18 between them, making full use of the mutual influence between the vibration sources to consume and absorb the vibration energy as much as possible ; The concrete platform is isolated from the anechoic chamber to avoid contact and rigid connection, or use special vibration isolation measures for connection.

The turbulence control panel 5 is arranged at the inlet of the fan supercharging stage test piece 6 to rectify the inlet flow field, control the inlet flow field and inlet airflow distortion, and solve the problems existing in the airflow entering the inlet of the turbofan engine during the ground static test. Steady-state, unsteady-state distortion or turbulence problems, to achieve the purpose of simulating the air intake conditions of the engine in flight and eliminating "extra" noise.

A far-field microphone array is arranged at a distance away from the inlet of the fan booster test piece 6 that is not less than 15 times the diameter of the fan booster test piece 6; the angular interval between each microphone is not more than 5°, and the test angle range is 5°-120°, satisfying that the distance from the far-field microphone array 3 to the inlet of the fan booster test piece 6 should meet the far-field radiation conditions of the fan sound source, and the distance between the far-field microphone array 3 and the wall of the anechoic room should be kept. Less than 3m; avoid the influence of the wall of the anechoic chamber and the anechoic wedge on the microphone test.

The roof of the anechoic chamber 1 is provided with a large-span self-supporting steel frame support structure 13, and the top of the support structure is provided with a protective structure 14. The protective structure 14 is connected to the support structure 13 through a triangular interactive connection structure 15, and the lower surface of the support structure 13 Installed with muffling wedge 4;

The protection structure 14 includes: a shale protection layer, a polyester tire belt protection layer, a leveling layer and a hydrophobic perlite insulation layer arranged from top to bottom. On the one hand, this part of the structure ensures the conventional functions such as heat insulation and waterproof of the roof of the anechoic chamber; it meets the requirements of no column support, has a strong self-supporting structure, can support the laying of large-area wedges, good sound insulation, and good Waterproof characteristics and other requirements.

The lower surface of the supporting structure is equipped with anechoic wedge 4, the cut-off frequency of the anechoic wedge 4 is more than 70% of the lowest frequency of the test noise in the anechoic chamber, and the surface of the anechoic wedge is made of non-metallic panel material to avoid the existence of high-frequency noise Acoustic failure, the anechoic wedge should have a sound absorption coefficient of not less than 0.99 within the frequency range of the noise being tested. Lightweight, high-performance wedges are used, and a new type of mounting bracket structure design is adopted. The form is novel, light and flexible. Under the condition of ensuring convenient installation, it effectively solves the problem of wedge positioning, and fully ensures that the anechoic wedge has a sufficient back cavity, and improves the sound absorption ability of the wedge for low-frequency sound waves.

Inner and outer culvert exhaust system is made up of inner channel 12, outer channel 10 and exhaust muffler tower 11; inner and outer channel exhaust system comprises exhaust volute, and the rear end of inner channel 12 and outer channel 10 is connected with The exhaust muffler tower 11 is connected, and the front ends of the inner duct 12 and the outer duct 10 are connected with the fan booster stage test piece 6

The air intake system 2 is made up of an air intake deflector and an air intake muffler tower. The air intake guide device 19 is arranged in the air intake muffler tower 20. The muffler 22, the air flow enters the filter device and the muffler successively through the air intake device 21, and enters the muffler chamber through the air intake guide device 19;

The filter device is arranged in the air intake device 21, and is composed of an air intake louver 23, a stainless steel protective net 24, an electric rolling door 25 and a G4 grade filter 26;

The stainless steel protective net 24 is close to the outside of the air inlet of the air intake device 21, mainly preventing sundries such as fallen leaves from entering;

The G4 grade filter 26 is arranged on the inner side of the air inlet of the air intake device 21, and finally filters the air intake air during the experiment to filter out dust and the like;

The air intake louver 23 is arranged on the side of the stainless steel protective net 24 away from the G4 grade filter 26, mainly preventing birds, wind and sand, rain and snow, etc. from entering the air intake muffler tower 20;

The electric rolling shutter door 25 is arranged on the side of the G4 grade filter 26 close to the stainless steel protective net 24; it is used to ensure that the air intake muffler tower 20 is not polluted by any foreign matter during the non-test period;

A closed cavity is provided between the stainless steel protective net 24 and the G4 grade filter 26, and a monitoring device 27 is provided in the closed cavity for checking the integrity of the appearance of the filter device.

The above air intake system 2 meets the design requirements of the anechoic chamber air intake system with open type, large air flow, and low noise reflection, ensuring that the air intake air has a uniform and smooth flow path, and reduces air flow distortion and flow loss.

There are 6 temperature and humidity detection points inside the anechoic chamber, and six points are arranged inside the anechoic chamber for temperature, humidity detection, and temperature gradient monitoring to avoid the influence of temperature gradient and other changes on the noise test results.

The selection of temperature and humidity detection points is based on the calculation results of the CFD flow field, with the fan booster stage test piece 6 as the center, uniformly distributed at three different radii and two different angles; determined after optimized selection. The principle of selection is to arrange temperature and humidity integrated sensors according to the position where there may be a large temperature gradient in the calculation results. At the same time, in order to accurately measure the temperature gradient along the longitudinal direction without affecting the acoustic measurement, a liftable electric hoist is specially used to install the temperature and humidity sensor, and the electric hoist is hidden in the wedge of the roof to reduce the sound wave reflection surface. At the same time, a temperature and humidity correction program was developed in combination with the test frequency range to achieve the ability to accurately obtain the high-frequency noise radiation law and characteristics of the scaled fan supercharger test piece.

The anechoic chamber also includes the acoustic characteristic detection system of the anechoic wedge and the anechoic chamber, and the acoustic characteristic detection system of the anechoic wedge and the anechoic chamber includes: a medium-high frequency sound source 28, an acoustic waveguide (optional) 29, a test stand 30, Microphone 31, guy wire 32, data acquisition device 33 and control device 34;

When testing the acoustic characteristics of the anechoic chamber, it is necessary to connect the acoustic waveguide 29 through the anechoic chamber 1 to the medium-high frequency sound source 28. The installation axis of the acoustic waveguide 29 is at the same height as the center line of the anechoic chamber. 28 transmits sound waves to the anechoic chamber through the sound waveguide 29; when the radiation sound field of the middle and high frequency sound source 28 has good uniform characteristics, the sound waveguide 29 can not be used, but the middle and high frequency sound source 28 can be directly placed in the anechoic chamber 1, and the middle and high frequency The installation axis of the high-frequency sound source 28 is located at the same height as the center line of the anechoic chamber to be checked, and the medium-high frequency sound source 28 directly transmits sound waves to the anechoic chamber.

When testing the acoustic characteristics of the anechoic wedge, it is necessary to connect the acoustic waveguide 29 through the anechoic chamber 1 to the medium-high frequency sound source 28. The installation axis of the acoustic waveguide 29 is at the same height as the center line of the anechoic wedge and the anechoic chamber. The medium and high frequency sound source 28 transmits sound waves to the anechoic chamber through the sound waveguide 29; when the radiation sound field of the medium and high frequency sound source 28 has good uniform characteristics, the medium and high frequency sound source 28 can be directly placed in the anechoic chamber 1 without using the sound waveguide 29 , and make the installation axis of the middle and high frequency sound source 28 be at the same height as the anechoic wedge sample to be tested and the center line of the anechoic chamber, and the middle and high frequency sound source 28 directly transmits sound waves to the anechoic chamber.

The test support 30 is arranged between the acoustic waveguide 29 and the wedge sample (or the anechoic chamber). The test support 30 front end is equipped with a microphone 31 and a data acquisition device 33. The guy wire 32 moves between the wedge sample (or the anechoic chamber) and the acoustic waveguide 29.

The acoustic characteristic detection system of the anechoic wedge and the anechoic chamber can obtain the attenuation characteristics of the sound pressure along the propagation path with the propagation distance. By comparison, the sound absorption characteristics of the sound absorption wedge in the middle and high frequency bands can be obtained.

The detection system for acoustic characteristics of anechoic wedge and anechoic chamber generally has the disadvantage of poor sound field uniformity for existing medium and high frequency sound sources. Based on the characteristics of small loss and flat wave front when the sound wave propagates inside the pipe with a suitable diameter, a medium-high-frequency sound source system with good uniformity of the sound field is formed, which solves the problem of elimination Acoustic spikes and sound source issues for high frequency detection in anechoic chambers.

The test support 30 comprises a sensor support, a lifting measuring head, and a laser positioner. The sensor support is composed of a base, a lower pole, an upper pole, a pulley cable structure and industrial universal casters;

The base is square, and the four bottom corners are respectively installed with industrial universal casters. The base is installed with a lower pole and an upper pole in sequence from bottom to top. A pulley cable structure is installed on the axis of the top of the upper pole, which is perpendicular to the axis of the upper pole. The direction is equipped with a laser positioner and a lifting measuring head; the above-mentioned test system can realize the functions of vertical height adjustment, horizontal stepless adjustment, small position error and low reflection coefficient. It meets the requirements of low noise reflection and high positioning accuracy of the test stand in the high frequency (up to 40kHz) noise test environment.

The present invention proposes an anechoic chamber for the aerodynamic noise test of the fan pressurized stage, which adopts an asymmetric layout and a large-span steel-concrete structure roof design, the tester adopts a vibration isolation design, and the air intake system adopts an open type and low noise Reflective design, the entrance of the test piece adopts turbulent flow control technology, monitors and adopts correction methods to suppress the influence of temperature and humidity, and the sensor bracket adopts high-precision test brackets, which meets the noise test requirements of large anechoic chambers and overcomes the excessive construction cost of the existing anechoic chambers. High problems and high frequency verification and other problems.

Finally, it should be pointed out that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that: they can still modify the technical solutions described in the aforementioned embodiments, or perform equivalent replacements for some of the technical features; and these The modification or replacement does not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims (9)

1. a kind of anechoic room for fan forced grade aerodynamic noise test characterized by comprising exerciser, inside and outside culvert row Gas system, gas handling system (2), turbulence control screen (5)；

The anechoic room (1) is asymmetry structure, and two adjacent walls in one corner of anechoic room are biased to anechoic room direction, shape At installation space, fan forced grade testpieces (6), wall are installed on the inside of the wherein wall in two adjacent walls of the biasing Outside be provided with inside and outside culvert exhaust system and exerciser, fan forced grade testpieces (6) entrance is being provided with far field Microphone array (3), distance of the far field microphone array (3) away from fan forced grade testpieces (6) entrance are not less than 15 Fan forced grade testpieces (6) diameter again；The turbulence control screen (5) is arranged in the fan forced grade testpieces (6) Entrance location is rectified to the inlet flow field to the fan forced grade testpieces (6), control inlet flow field and inhibit into Mouth inlet distortion；

The exerciser, inside and outside culvert exhaust system, fan forced grade testpieces (6) arrange that each system axle center is protected along same axis It holds consistent；

The gas handling system (2) connect with the air inlet of anechoic room, the inside and outside culvert exhaust system and fan forced grade testpieces (6) it connects, the exerciser is connected with inside and outside culvert exhaust system, passes through the transmission shaft and fan in inside and outside culvert exhaust system Booster stage testpieces (6) connection, provides power for it；

It is isolated between the inside and outside culvert exhaust system and exerciser and the anechoic room (1) using wall, the wall of the anechoic room Body is two-layer wall, and cavity is reserved between wall or filling radiation sound-absorbing material, the centre-height of the anechoic room are set as 5-8 times of fan forced grade testpieces (6) diameter；

The far field microphone array (3) is uniformly distributed in arc-shaped centered on fan forced grade testpieces (6) entrance, Mei Gechuan Angle interval between sound device is not more than 5 °, and test angle range is 5 ° -120 °, and the far field microphone array (3) is to disappearing The distance of the wall of sound chamber (1) is not less than 3m；

The noise elimination indoor location noise elimination wedge, the noise elimination wedge cutoff frequency are anechoic room test noise low-limit frequency 70% or more, and noise elimination wedge acoustic absorptivity in the frequency range of institute's test noise is not less than 0.99.

2. the anechoic room according to claim 1 for fan forced grade aerodynamic noise test, it is characterised in that: described to disappear Sound chamber (1) roof is provided with large span and is provided with protection knot from the top of load steelframe support construction (13), the support construction Structure (14), the protection structure (14) is connect by triangle interactive mode connection structure (15) with the support construction (13), described The lower surface of support construction (13) is equipped with noise elimination wedge (4)；

Protection structure (14) includes: the shale protective layer being arranged from top to bottom, polyester blank band protective layer, screed-coat and hydrophobic Pearlite insulating layer.

3. the anechoic room according to claim 1 for fan forced grade aerodynamic noise test, it is characterised in that: described Inside and outside culvert exhaust system is made of main duct (12), by-pass air duct (10) and exhausting silencer tower (11), the main duct (12) and outer The rear end of duct (10) is connect with exhausting silencer tower (11), and the front end of the main duct (12) and by-pass air duct (10) is increased by fan Testpieces (6) of arbitrarily downgrading is connect with the anechoic room (1).

4. the anechoic room according to claim 1 for fan forced grade aerodynamic noise test, it is characterised in that: the examination It tests device to be made of motor (7), gear-box (8) and torsion axis (9), and the exerciser connects the inside and outside culvert row by turning round axis (9) Gas system, and connect by the inside and outside transmission shaft for containing exhaust system with fan forced grade testpieces (6), the motor (7), gear-box (8), torsion axis (9) are sequentially connected, and are co-located on same concrete platform, the concrete platform and noise elimination Room isolation；

The concrete platform is formed by upper layer basis (16), subfoundation (17) and positioned at cushion blocking (18) between the two.

5. the anechoic room according to claim 1 for fan forced grade aerodynamic noise test, it is characterised in that: it is described into Gas system (2) is made of air intake guiding unit (19) and intake noise reduction tower (20)；

In intake noise reduction tower (20), the intake noise reduction tower (20) is provided with air inlet dress for air intake guiding unit (19) setting (21), filter device and silencer (22) are set, air-flow sequentially enters filter device and silencer through inlet duct (21), through described Air intake guiding unit (19) enters in anechoic room；

The filter device setting is in inlet duct (21), by air inlet louver (23), stainless steel protective net (24), electric rolling Door (25) and G4 grades of filter (26) compositions；

The stainless steel protective net (24) is close to the outside of the air flow inlet of the inlet duct (21), the G4 grades of filter (26) setting is protected in the inside of the inlet duct (21) air flow inlet, air inlet louver (23) setting in the stainless steel Side of the net (24) far from the G4 grades of filter (26), the electric rolling door (25) are arranged in the G4 grades of filter (26) Close to the side of the stainless steel protective net (24)；

Closed cavity is provided between the stainless steel protective net (24) and the G4 grades of filter (26), in the closed cavity It is provided with monitoring device (27).

6. the anechoic room according to claim 1 for fan forced grade aerodynamic noise test, it is characterised in that: the rapids Flow control screen (5) is made of multiple turbulence control units, is able to solve air inlet turbulent flow existing for surface noise test process and is caused Surface noise test result can not reflect the noise problem under airflight state；On the other hand it is able to solve and is disappeared using asymmetric After sound chamber's layout designs, cause that inlet flow field is asymmetric, air inlet turbulivity further increases, leads to the problem of additional noise.

7. the anechoic room according to claim 1 for fan forced grade aerodynamic noise test, it is characterised in that: described to disappear Sound chamber is internally provided with Temperature and Humidity point, and the Temperature and Humidity point is in 6 bit distributions, to carry out temperature, humidity inspection It surveys, temperature gradient monitoring；

The selection of the Temperature and Humidity point is foundation based on the calculated result in the flow field CFD, is with fan forced grade testpieces (6) Center, three different radiuses and two different angles are evenly distributed with.

8. the anechoic room according to claim 1 for fan forced grade aerodynamic noise test, it is characterised in that: described to disappear Sound chamber further includes noise elimination wedge and anechoic room acoustic characteristic detection system；

The noise elimination wedge and anechoic room acoustic characteristic detection system include: medium-high frequency sound source (28), acoustic waveguide tube (29), test Bracket (30), microphone (31), bracing wire steel wire (32), data acquisition device (33) and control device (34)；

When carrying out anechoic room acoustic characteristic detection, the acoustic waveguide tube (29) passes through the anechoic room (1) and medium-high frequency sound Source (28) connection, acoustic waveguide tube (29) mounting axis and the anechoic room center line are located on sustained height, the middle height Frequency sound source (28) is by transmitting sound wave in the acoustic waveguide tube (29) Xiang Suoshu anechoic room；High-frequency sound source (28) radiated sound field in the middle It when with good uniform properties, does not use acoustic waveguide tube (29), and medium-high frequency sound source (28) is directly placed in the noise elimination In room (1), and medium-high frequency sound source (28) mounting axis and the anechoic room center line to be checked are located on sustained height, institute It states medium-high frequency sound source (28) and directly transmits sound wave into the anechoic room；

When carrying out noise elimination wedge acoustic characteristic detection, the acoustic waveguide tube (29) need to be passed through anechoic room (1) and medium-high frequency Sound source (28) connection, acoustic waveguide tube (29) mounting axis are located on sustained height with wedge to be checked and anechoic room center line, The medium-high frequency sound source (28) transmits sound wave into anechoic room by the acoustic waveguide tube (29)；High-frequency sound source (28) radiates in the middle It when sound field has good uniform properties, does not use acoustic waveguide tube (29), and medium-high frequency sound source (28) is directly placed in noise elimination In room (1), and it is same that medium-high frequency sound source (28) mounting axis and noise elimination wedge exemplar to be checked and anechoic room center line are located at In one height, the medium-high frequency sound source (28) directly transmits sound wave into anechoic room；

The test bracket (30) is arranged between the acoustic waveguide tube (29) and wedge exemplar or the anechoic room, the test The microphone (31) is installed in bracket (30) front end and data acquisition device (33), the test bracket (30) fill in the control It sets under (34) control, it can be along the bracing wire steel wire (32) in the wedge exemplar or the anechoic room and the acoustic waveguide tube (29) it is moved between.

9. the anechoic room according to claim 8 for fan forced grade aerodynamic noise test, it is characterised in that: the survey Try bracket (30) include sensor stand, lifting measuring head, laser locator, the sensor stand by pedestal, lower fulcrum bar, on Strut, pulley wire rope structure and industrial universal caster wheel composition；

The pedestal is square, and mounting industrial universal caster wheels are distinguished at four base angles, pedestal by it is lower and on be successively vertically installed with down Strut and upper rack posts, upper rack posts top axis direction is equipped with pulley wire rope structure, perpendicular to the direction of upper rack posts axis It is provided with laser locator and lifting measuring head.