Open direct-current wind tunnel for double-duct jet flow noise test

Abstract

The invention discloses an open direct-current wind tunnel for a double-duct jet flow noise test, belongs to the technical field of wind tunnel tests, and aims to solve the problem that a cold and hot double-duct jet flow noise test wind tunnel does not exist at present. Comprising a silencing air inlet device, a square-round transition section, a front contraction section, an air inlet corner section, a power section, a large-angle diffusion section, a stable section and a rear contraction section which are connected in sequence, and further comprises a collector, a small-angle diffusion section, an exhaust corner section, a round-square transition section and a silencing exhaust device which are connected in sequence, the rear contraction section and the collector are both located in the anechoic chamber, the rear contraction section and the collector are coaxially aligned in a front-back spaced mode, the air supply device is arranged at the tail end of the rear contraction section, and the microphones are arranged in the anechoic chamber. And powerful technical support is provided for low-noise design of commercial engines in China.

Description

Technical Field

[0001] The invention belongs to the technical field of wind tunnel tests, and in particular relates to an open direct current wind tunnel for double-duct jet noise tests. Background Art

[0002] In recent years, with the development of my country's civil aviation industry, civil aircraft have become an important means of transportation for people to travel. In order to improve the comfort of aviation flights, higher requirements have been put forward for the research and development of aircraft engines. There is an urgent need for a jet noise tester with the ability to simulate incoming flow, cold and hot double-duct jet simulation capabilities, and acoustic test environment. It is used to study the mechanism and characteristics of aircraft engine jet noise, verify the low-noise nozzle design technology, and be able to control the jet temperature, pressure ratio, and incoming flow speed, and simulate the engine jet noise under different working conditions. At present, there is no cold and hot double-duct jet noise test wind tunnel in China, so it is urgent to develop a double-duct jet noise DC wind tunnel for the development and testing of aircraft engines. Summary of the invention

[0003] The purpose of the present invention is to provide an open DC wind tunnel for double duct jet noise test, so as to solve the problem that there is no hot and cold double duct jet noise test wind tunnel at present. The technical solution adopted by the present invention is as follows:

[0004] An open DC wind tunnel for double duct jet noise test, comprising a muffler air intake device, a square-round transition section, a front contraction section, an air intake corner section, a power section, a large-angle diffuser section, a stable section and a rear contraction section connected in sequence, and also comprising a collector, a small-angle diffuser section, an exhaust corner section, a square-round transition section and a muffler exhaust device connected in sequence, the muffler air intake device, the square-round transition section and the front contraction section are arranged vertically, the power section, the large-angle diffuser section, the stable section, the rear contraction section and the collector, and the small-angle diffuser section are arranged horizontally, the square-round transition section and the muffler exhaust device are arranged vertically, the front end height of the muffler air intake device and the rear end height of the muffler exhaust device are both 18 meters to 22 meters from the installation ground, the rear contraction section and the collector are both in the muffler room, and the rear contraction section and the collector are coaxially aligned at intervals;

[0005] The air supply device includes a bracket and an inner tube and an outer tube connected with each other. The bracket is located below the rear contraction section. A cold air supply pipe and a hot air supply pipe are arranged on the bracket. The outer tube is coaxial with the rear contraction section. The front part of the outer tube extends into the rear contraction section. The upper end of the cold air supply pipe passes through the rear contraction section and is connected with the front end of the outer tube. The upper end of the hot air supply pipe passes through the rear contraction section and is connected with the front end of the inner tube. The parts of the cold air supply pipe and the hot air supply pipe in the rear contraction section and the outer cover of the outer tube are provided with fairings. An airflow channel is formed between the fairing and the rear contraction section. The parts of the cold air supply pipe and the hot air supply pipe outside the rear contraction section are provided with silencer packages.

[0006] With the terminal outlets of the inner tube and the outer tube as the center of the circle, an arc-shaped support rod is arranged in the anechoic chamber. The arc-shaped support rod is located on one side of the rear contraction section and the collector. Several microphones are arranged at intervals along the arc-shaped support rod. The microphones are at the same height as the terminal outlets of the inner tube and the outer tube.

[0007] Furthermore, the radius of the arc-shaped support rod is 10 meters, the number of microphones is 25, the 25 microphones are evenly arranged at intervals of 5°, and the measurement range of the 25 microphones is 40° to 160°.

[0008] Furthermore, two layers of columnar silencers are arranged in the front and rear of the silencer air intake device.

[0009] Furthermore, the outer shell of the power section is composed of a perforated plate tube, a melamine foam layer, a glass fiber cotton layer and a back plate tube which are coaxially sleeved in sequence from the inside to the outside.

[0010] Furthermore, the thickness of the melamine foam layer is 100 mm, the thickness of the glass fiber cotton layer is 300 mm, the thickness of the perforated plate tube is 1.5 mm, and the opening rate of the perforated plate tube is greater than or equal to 24%.

[0011] Furthermore, two layers of plate-type silencers are arranged at the front and rear of the stabilizing section.

[0012] Furthermore, the outer shells of the rear contraction section and the collector are wrapped with sound absorbing materials, and the outer shells of the stabilization section and the small-angle diffusion section in the inner part of the anechoic chamber are wrapped with sound absorbing materials.

[0013] Furthermore, a columnar silencer is provided in the silencer exhaust device.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] The present invention can achieve a maximum wind speed of 102m / s. The front inlet of the silencer intake device and the terminal outlet of the silencer exhaust device are both arranged at an altitude of about 20 meters, which is conducive to achieving the environmental noise standard. The above design can ensure that the data of the wind tunnel background noise at a wind speed of 80m / s meets the requirement that the background noise is less than 80 (dBA). The present invention has an acoustic test environment, and the air supply device can realize the cold and hot double duct jet simulation capability. The inner tube and the outer duct can realize the control of the jet temperature, pressure ratio and incoming flow velocity, and realize the simulation of the engine jet noise under different working conditions. The maximum temperature simulated by the inner tube can reach 950K, and the total pressure unevenness is not greater than ±1%. At the same time, it has the test capability of an open DC wind tunnel, which provides a strong technical support for the low-noise design of my country's commercial engines. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a front view of the present invention;

[0017] Figure 2 A top view of the present invention;

[0018] Figure 3 for Figure 1 A magnified image of point A;

[0019] Figure 4 is a schematic diagram of an arc-shaped support rod;

[0020] Figure 5 is a top view of a number of microphones arranged on an arc-shaped support rod;

[0021] Figure 6 It is a connection diagram of the outer tube, inner tube and fairing.

[0022] In the figure, 1. silencer intake device, 2. square-round transition section, 3. front contraction section, 4. intake corner section, 5. power section, 6. large-angle diffusion section, 7. stable section, 8. rear contraction section, 9. air supply device, 10. arc-shaped support rod, 11. collector, 12. silencer chamber, 13. small-angle diffusion section, 14. exhaust corner section, 15. round-square transition section, 16. silencer exhaust device, 17. bracket, 18. cold air supply pipe, 19. hot air supply pipe, 20. microphone, 21. outer culvert, 22. inner culvert, 23. fairing. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is described below by the specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0024] The connection mentioned in the present invention is divided into fixed connection and detachable connection. The fixed connection is a non-detachable connection including but not limited to conventional fixed connection methods such as folding connection, rivet connection, bonding connection and welding connection. The detachable connection includes but not limited to conventional detachable methods such as bolt connection, snap connection, pin connection and hinge connection. When the specific connection method is not clearly defined, it is assumed that at least one connection method can be found in the existing connection methods to achieve the function, and those skilled in the art can choose according to their needs. For example: welding connection is selected for fixed connection, and bolt connection is selected for detachable connection.

[0025] The present invention will be further described in detail below in conjunction with the accompanying drawings. The following embodiments are provided to explain the present invention, but the present invention is not limited to the following embodiments.

[0026] Example: Figure 1 to Figure 6As shown, an open DC wind tunnel for double duct jet noise test includes a silencer air intake device 1, a square-round transition section 2, a front contraction section 3, an air intake corner section 4, a power section 5, a large-angle diffuser section 6, a stabilizing section 7 and a rear contraction section 8 connected in sequence, and also includes a collector 11, a small-angle diffuser section 13, an exhaust corner section 14, a square-round transition section 15 and a silencer exhaust device 16 connected in sequence. The silencer air intake device 1, the square-round transition section 2 and the front contraction section 3 are arranged vertically, the power section 5, the large-angle diffuser section 6, the stabilizing section 7, the rear contraction section 8 and the collector 11, the small-angle diffuser section 13 are arranged horizontally, and the square-round transition section 15 and the silencer exhaust device 16 are arranged vertically. The front end height of the muffler intake device 1 and the end height of the muffler exhaust device 16 are both 18 meters to 22 meters from the installation ground. The rear contraction section 8 and the collector 11 are both in the muffler chamber 12. The rear contraction section 8 and the collector 11 are coaxially aligned at a front-to-back interval. According to the diffusion angle and maximum wind speed of the airflow ejected from the outlet at the end of the rear contraction section 8, the distance between the rear contraction section 8 and the collector 11, as well as the length of the open test section can be calculated by the outlet diameter of the rear contraction section 8 and the inlet diameter of the collector 11. In this application, the diffusion angle of the airflow ejected from the rear contraction section 8 is 5.3°, and the maximum wind speed is 102m / s. The length of the open test section can be calculated to be 11.2 meters;

[0027] The air supply device 9 includes a bracket 17 and an inner tube 22 and an outer tube 21 connected inside and outside. The bracket 17 is located below the rear contraction section 8. A cold air supply pipe 18 and a hot air supply pipe 19 are arranged on the bracket 17. The outer tube 21 is coaxial with the rear contraction section 8. The front part of the outer tube 21 extends into the rear contraction section 8. The terminal outlet of the outer tube 21 is located outside the rear contraction section 8. An annular cold air flow channel is formed between the inner tube 22 and the outer tube 21. The inner tube 22 is a hot air flow channel. The front end of the inner tube 22 passes through the front end of the outer tube 21. The upper end of the cold air supply pipe 18 passes through the rear contraction section 8 and is connected to the front end of the outer tube 21. The upper end of the hot air supply pipe 19 passes through the rear contraction section 8 and is connected to the inner tube 22. The front end of the inner tube 22 and the outer tube 21 are both open, the lower ends of the hot air supply pipe 19 and the cold air supply pipe 18 are connected to the compressor of the wind tunnel through pipelines, and the airflows flowing into the hot air supply pipe 19 and the cold air supply pipe 18 are heated by heaters respectively, so that the total temperature of the airflow in the cold air supply pipe 18 is increased from room temperature to 400K, and the airflow temperature in the hot air supply pipe 19 can reach 950K, and the parts of the cold air supply pipe 18 and the hot air supply pipe 19 in the rear contraction section 8 and the outer cover of the outer tube 21 are provided with a fairing 23, and the airflow flow channel is formed between the fairing 23 and the rear contraction section 8, and the parts of the cold air supply pipe 18 and the hot air supply pipe 19 outside the rear contraction section 8 are provided with a silencer package;

[0028] An arc-shaped support rod 10 is arranged in the muffler chamber 12 with the terminal outlets of the inner tube 22 and the outer tube 21 as the center of the circle. The arc-shaped support rod 10 is located on one side of the rear contraction section 8 and the collector 11. A plurality of microphones 20 are arranged at intervals along the arc-shaped support rod 10. The microphones 20 are at the same height as the terminal outlets of the inner tube 22 and the outer tube 21.

[0029] The radius of the arc-shaped support rod 10 is 10 meters, the number of the microphones 20 is 25, the 25 microphones 20 are evenly arranged at intervals of 5°, and the measurement range of the 25 microphones 20 is 40° to 160°.

[0030] Two layers of columnar silencers are arranged in the silencer air intake device 1 at the front and rear.

[0031] The outer shell of the power section 5 is composed of a perforated plate tube, a melamine foam layer, a glass fiber cotton layer and a back plate tube which are sequentially sleeved from the inside to the outside.

[0032] The thickness of the melamine foam layer is 100 mm, the thickness of the glass fiber cotton layer is 300 mm, the thickness of the perforated plate tube is 1.5 mm, and the opening rate of the perforated plate tube is greater than or equal to 24%.

[0033] Two layers of plate-type silencers are arranged in the front and rear of the stabilizing section 7.

[0034] The outer shells of the rear contraction section 8 and the collector 11 are wrapped with sound absorbing materials, and the outer shells of the stabilization section 7 and the diffusion section 13 in the muffler chamber 12 are wrapped with sound absorbing materials.

[0035] A columnar silencer is arranged in the silencer exhaust device 16 .

[0036] The fan is driven by the motor of the power section 5, and the gas enters the wind tunnel from the silencer intake device 1, passes through the stabilizing section 7 and the rear contraction section 8, enters the silencer chamber 12, and then passes through the diffusion section 13, the exhaust corner section 14, and the silencer exhaust device 16 in sequence to be discharged into the atmosphere. The present invention can achieve a maximum wind speed of 102m / s. The front inlet of the silencer intake device 1 and the terminal outlet of the silencer exhaust device 16 are both set at a height of about 20 meters above the ground, which is conducive to achieving the environmental noise standard. The above design can ensure that the background noise of the wind tunnel at a wind speed of 80m / s meets the requirement that the background noise is less than 80 (dBA).

[0037] The present invention has an acoustic test environment, the air supply device 9 can realize the cold and hot double-duct jet simulation capability, the inner tube 22 and the outer tube 21 can realize the control of the jet temperature, pressure ratio and incoming flow velocity, and realize the simulation of the engine jet noise under different working conditions, and the maximum simulated temperature of the inner tube 22 can reach 950K, and the total pressure unevenness is not more than ±1%. At the same time, it has the test capability of an open DC wind tunnel, which provides strong technical support for the low-noise design of my country's commercial engines.

[0038] The above embodiments are merely exemplary descriptions of the present invention and do not limit its protection scope. Those skilled in the art may also make partial changes thereto, which are within the protection scope of the present invention as long as they do not exceed the spirit of the present invention.

Claims

1. An open DC wind tunnel for double-ducted jet noise testing, characterized by: The invention comprises a silencer air intake device (1), a square-round transition section (2), a front contraction section (3), an air intake corner section (4), a power section (5), a large-angle diffusion section (6), a stabilization section (7) and a rear contraction section (8) which are connected in sequence, and also comprises a collector (11), a small-angle diffusion section (13), an exhaust corner section (14), a square-round transition section (15) and a silencer exhaust device (16) which are connected in sequence. The silencer air intake device (1), the square-round transition section (2) and the front contraction section (3) are arranged vertically, and the power section (5) , a large-angle diffusion section (6), a stabilizing section (7), a rear contraction section (8), a collector (11), and a small-angle diffusion section (13) are arranged horizontally, a round-square transition section (15) and a silencer exhaust device (16) are arranged vertically, a front end height of the silencer air intake device (1) and a rear end height of the silencer exhaust device (16) are both 18 meters to 22 meters from the installation ground, the rear contraction section (8) and the collector (11) are both located in the silencer chamber (12), and the rear contraction section (8) and the collector (11) are coaxially aligned at a front-to-rear interval; The air supply device (9) comprises a support (17) and an inner tube (22) and an outer tube (21) connected inside and outside. The support (17) is located below the rear contraction section (8). A cold air supply pipe (18) and a hot air supply pipe (19) are provided on the support (17). The outer tube (21) is coaxial with the rear contraction section (8). The front part of the outer tube (21) extends into the rear contraction section (8). The upper end of the cold air supply pipe (18) passes through the rear contraction section (8) and is connected to the front end of the outer tube (21). The upper end of the hot air supply pipe (19) passes through the rear contraction section (8) and is connected to the front end of the inner tube (22); the cold air supply pipe (18) and the hot air supply pipe (19) are located in the rear contraction section (8) and the outer cover of the outer tube (21) are provided with a fairing (23); an air flow channel is formed between the fairing (23) and the rear contraction section (8); and the cold air supply pipe (18) and the hot air supply pipe (19) are located outside the rear contraction section (8) and are provided with a sound-absorbing package; An arc-shaped support rod (10) is arranged in a muffler chamber (12) with the end outlets of an inner tube (22) and an outer tube (21) as the center of a circle. The arc-shaped support rod (10) is located on one side of a rear contraction section (8) and a collector (11). A plurality of microphones (20) are arranged at intervals along the arc-shaped support rod (10). The microphones (20) are at the same height as the end outlets of the inner tube (22) and the outer tube (21).

2. An open DC wind tunnel for double duct jet noise testing according to claim 1, characterized in that: The radius of the arc-shaped support rod (10) is 10 meters, the number of microphones (20) is 25, the 25 microphones (20) are evenly arranged at intervals of 5 degrees, and the measurement range of the 25 microphones (20) is 40 degrees to 160 degrees.

3. An open DC wind tunnel for double duct jet noise testing according to claim 1, characterized in that: Two layers of columnar silencers are arranged at the front and rear of the silencer air intake device (1).

4. An open DC wind tunnel for double duct jet noise testing according to claim 1, characterized in that: The outer shell of the power section (5) is composed of a perforated plate tube, a melamine foam layer, a glass fiber cotton layer and a back plate tube which are coaxially sleeved in sequence from the inside to the outside.

5. An open DC wind tunnel for double duct jet noise testing according to claim 4, characterized in that: The thickness of the melamine foam layer is 100 mm, the thickness of the glass fiber cotton layer is 300 mm, the thickness of the perforated plate tube is 1.5 mm, and the opening rate of the perforated plate tube is greater than or equal to 24%.

6. An open DC wind tunnel for double duct jet noise testing according to claim 1, characterized in that: Two layers of sheet-type silencers are arranged in the front and rear of the stabilizing section (7).

7. An open DC wind tunnel for double duct jet noise testing according to claim 1, characterized in that: The outer shells of the rear contraction section (8) and the collector (11) are both wrapped with sound absorbing materials, and the outer shells of the stabilization section (7) and the small-angle diffusion section (13) located inside the anechoic chamber (12) are both wrapped with sound absorbing materials.

8. An open DC wind tunnel for double duct jet noise testing according to any one of claims 1 to 7, characterized in that: A columnar silencer is arranged in the silencer exhaust device (16).

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